ORCID Profile
0000-0001-8076-8789
Current Organisations
Sunshine Coast Hospital and Health Service
,
University of the Sunshine Coast
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Publisher: Wiley
Date: 09-01-2023
DOI: 10.1113/EP090813
Abstract: What is the central question of this study? We sought to investigate whether peripheral and cerebrovascular function are impaired in early and late postmenopausal females compared with premenopausal females, while also accounting for nitric oxide and estradiol levels. What is the main finding and its importance? We observed no differences in peripheral vascular and cerebrovascular function between healthy and physically active premenopausal females and early and late postmenopausal females. Our findings contradict previous cross‐sectional observations of vascular and cerebrovascular dysfunction across menopause. Longitudinal studies assessing vascular and cerebrovascular outcomes across the menopausal transition are warranted. The risk of cardiovascular and cerebrovascular disease increases in ageing females, coinciding with the onset of menopause. Differences in peripheral and cerebrovascular function across menopausal stages, however, are poorly characterized. The aim of this study was to compare peripheral and cerebrovascular function between healthy premenopausal (PRE), early (1–6 years after final menstrual period E‐POST) and late ( years after final menstrual period L‐POST) postmenopausal females. We also explored the association between reproductive hormones, NO bioavailability and cerebrovascular function. In 39 females (40–65 years of age), we measured arterial stiffness, brachial artery flow‐mediated dilatation, and cerebrovascular reactivity (CVR) to hypercapnia in the middle (MCAv) and internal (ICA) carotid arteries. Follicle‐stimulating hormone, estradiol, progesterone and plasma nitrate and nitrite concentrations were also measured. Years since final menstrual period (PRE, 0 ± 0 years E‐POST, 3 ± 1 years L‐POST, 11 ± 4 years P 0.001) and estradiol levels (PRE, 145.5 ± 65.6 pg ml −1 E‐POSTm 30.2 ± 81.2 pg ml −1 L‐POST, 7.7 ± 11.3 pg ml −1 P 0.001) were different between groups. All groups exceeded the guidelines for recommended physical activity. There were no group differences in blood pressure ( P = 0.382), arterial stiffness ( P = 0.129), flow‐mediated dilatation ( P = 0.696) or MCAv CVR ( P = 0.442). The ICA CVR blood flow response was lower in PRE compared with L‐POST (26.5 ± 19.2 vs. 47.8 ± 12.6% P = 0.010), but after adjusting for age these differences were no longer present. Flow‐mediated dilatation ( r = 0.313, P = 0.105) and ICA CVR ( r = −0.154, P = 0.495) were not associated with the estradiol concentration. There were no associations between the estradiol concentration and NO bioavailability. These results suggest that in healthy, physically active early and late postmenopausal females, vascular and cerebrovascular function is generally well preserved.
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.PHYSBEH.2019.04.021
Abstract: Previous studies showed a decrease in reaction time during the weightlessness phase of a parabolic flight. This effect was found to be stronger with increasing task complexity and was independent of previous experience of weightlessness as well as anti-nausea medication. Analysis of event related potentials showed a decreased litude of the N100-P200 complex in weightlessness but was not able to distinguish a possible effect of task complexity. The present study aimed to extend this previous work, by comparing behavioral (reaction time) and neurological (event related potentials analysis) performance to a simple (oddball) and a complex (mental arithmetic + oddball) task during weightlessness. 28 participants participated in two experiments. 11 participants performed a simple oddball experiment in the 1G and 0G phases of a parabolic flight. 17 participants were presented a complex arithmetic task in combination with an oddball task during the 1G and 0G phases of a parabolic flight. Reaction time as well as event related potentials (ERP) were assessed. Results revealed a reduced reaction time (p < .05) for the complex task during 0G. No gravity effects on reaction time were found for the simple task. In both experiments a reduction of typical ERP litudes was noticeable in weightlessness. It is assumed that the weightlessness induced fluid shift to the brain is positively affecting neuro-behavioral performance.
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/523250
Abstract: Virtual reality environments are increasingly being used to encourage in iduals to exercise more regularly, including as part of treatment those with mental health or neurological disorders. The success of virtual environments likely depends on whether a sense of presence can be established, where participants become fully immersed in the virtual environment. Exposure to virtual environments is associated with physiological responses, including cortical activation changes. Whether the addition of a real exercise within a virtual environment alters sense of presence perception, or the accompanying physiological changes, is not known. In a randomized and controlled study design, moderate-intensity Exercise (i.e., self-paced cycling) and No-Exercise (i.e., automatic propulsion) trials were performed within three levels of virtual environment exposure. Each trial was 5 minutes in duration and was followed by posttrial assessments of heart rate, perceived sense of presence, EEG, and mental state. Changes in psychological strain and physical state were generally mirrored by neural activation patterns. Furthermore, these changes indicated that exercise augments the demands of virtual environment exposures and this likely contributed to an enhanced sense of presence.
Publisher: Wiley
Date: 04-2015
DOI: 10.1111/CPF.12143
Abstract: This study compared blood pressure, heart rate variability (HRV) and forearm blood flow, at rest and in response to sympathoexcitatory stressors between normotensive and mildly hypertensive participants. Participants aged 30-79 years with normal blood pressure (n = 49) or mild hypertension (n = 17), with no history of taking antihypertensive medication, were recruited. Participants completed a cold pressor test (CPT) followed by an ischaemic handgrip test (IHGT). Blood pressure, HRV, forearm blood flow and vascular resistance were measured at rest and in response to each test. The CPT and IHGT evoked greater increases in mean arterial blood pressure in hypertensive participants (CPT: 10 ± 2 mmHg, IHGT: 9 ± 1 mmHg) compared with normotensive participants (CPT: 5 ± 1 mmHg, IHGT: 3 ± 1 mmHg P < 0.05). Resting high frequency power, which is a parameter of HRV associated with parasympathetic cardiac modulation, was lower in hypertensive participants (hypertensive: 31.73 ± 4.07 nu normotensive: 42.08 ± 2.22 nu P = 0.026) and was negatively correlated with systolic blood pressure (r = -0.272, P = 0.03) and mean arterial pressure across all participants (r = -0.258, P < 0.05). There were no differences in HRV or forearm blood flow responses to the CPT or IHGT between groups. This study demonstrated that sympathoexcitatory stress evoked by the CPT and IHGT induces an augmented blood pressure response in in iduals with mild hypertension, which supports the notion that autonomic dysfunction is likely to contribute to the pathogenesis of hypertension. It remains to be determined whether the hypertensive response is mediated through alterations in cardiac activity, peripheral vascular resistance or both.
Publisher: American Physiological Society
Date: 03-2020
Publisher: Human Kinetics
Date: 08-2018
Abstract: Purpose : To examine the effect of postexercise cold-water immersion (CWI) protocols, compared with control (CON), on the magnitude and time course of core temperature ( T c ) responses. Methods : Pooled-data analyses were used to examine the T c responses of 157 subjects from previous postexercise CWI trials in the authors’ laboratories. CWI protocols varied with different combinations of temperature, duration, immersion depth, and mode (continuous vs intermittent). T c was examined as a double difference (ΔΔ T c ), calculated as the change in T c in CWI condition minus the corresponding change in CON. The effect of CWI on ΔΔ T c was assessed using separate linear mixed models across 2 time components (component 1, immersion component 2, postintervention). Results : Intermittent CWI resulted in a mean decrease in ΔΔ T c that was 0.25°C (0.10°C) (estimate [SE]) greater than continuous CWI during the immersion component ( P = .02). There was a significant effect of CWI temperature during the immersion component ( P = .05), where reductions in water temperature of 1°C resulted in decreases in ΔΔ T c of 0.03°C (0.01°C). Similarly, the effect of CWI duration was significant during the immersion component ( P = .01), where every 1 min of immersion resulted in a decrease in ΔΔ T c of 0.02°C (0.01°C). The peak difference in T c between the CWI and CON interventions during the postimmersion component occurred at 60 min postintervention. Conclusions : Variations in CWI mode, duration, and temperature may have a significant effect on the extent of change in T c . Careful consideration should be given to determine the optimal amount of core cooling before deciding which combination of protocol factors to prescribe.
Publisher: Informa UK Limited
Date: 11-02-2016
Publisher: Springer Science and Business Media LLC
Date: 06-05-2022
DOI: 10.1007/S00421-022-04956-W
Abstract: Our aim was to compare cerebrovascular and systemic vascular function between older adults with and without mild cognitive impairment (MCI), and to determine which measures of vascular function best predict the presence of MCI. In 41 adults with MCI and 33 adults without MCI (control) we compared middle cerebral artery velocity (MCAv) and cerebrovascular pulsatility index (PI) at rest, cerebrovascular reactivity to CO 2 , and responsiveness to changes in blood pressure (%∆MCAv/%∆MAP). Systemic vascular function was assessed by flow-mediated dilation (FMD) and stiffness by pulse wave velocity (PWV). Cerebrovascular PI was higher in MCI compared with control (mean ± SD: 1.17 ± 0.27 vs. 1.04 ± 0.21), and MCI exhibited a lower %∆MCAv/%∆MAP (1.26 ± 0.44 vs. 1.50 ± 0.55%). Absolute ( p = 0.76) and relative cerebrovascular reactivity to CO 2 ( p = 0.34) was similar between MCI and control. When age was included as a covariate the significant difference in cerebral PI between groups was lost. PWV was higher (13.2 ± 2.2 vs. 11.3 ± 2.5 m s −1 ) and FMD% (4.41 ± 1.70 vs. 5.43 ± 2.15%) was lower in MCI compared with control. FMD% was positively associated with PI across the cohort. Logistic regression analysis indicated that FMD and PWV significantly discriminated between MCI and controls, independent of age, whereas the inclusion of cerebrovascular measures did not improve the predictive accuracy of the model. These findings raise the possibility that early changes in systemic vascular stiffness and endothelial function may contribute to altered cerebrovascular haemodynamics and impaired cognitive function, and present potential targets for prevention and treatment strategies in people with MCI.
Publisher: Elsevier BV
Date: 10-2009
DOI: 10.1016/J.PHYSBEH.2009.07.010
Abstract: Exercise is well known to result in changes of brain cortical activity measured by EEG. The aim of this study was (1) to localise exercise induced changes in brain cortical activity using a distributed source localisation algorithm and (2) to show that the effects of exercise are linked to participants' physical exercise preferences. Electrocortical activity (5 min) and metabolical parameters (heart rate, lactate, peak oxygen uptake) of eleven recreational runners were recorded before and after incremental treadmill, arm crank and bicycle ergometry. Electroencephalographic activity was localised using standardised low resolution brain electromagnetic tomography (sLORETA). Results revealed an increase in frontal alpha activity immediately post exercise whereas increases after bike exercise were found to be localised in parietal regions. All three kinds of exercise resulted in an increase of beta activity in Brodmann area 7. Fifteen and thirty minutes post exercise a specific activation pattern (decrease in frontal brain activity-increase in occipital regions) was noticeable for treadmill and bike but not arm crank exercise. We conclude that specific brain activation patterns are linked to different kinds of exercise and participants' physical exercise preferences.
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.ATHEROSCLEROSIS.2015.12.029
Abstract: Peripheral arterial disease (PAD) is characterised by impaired leg blood flow, which contributes to claudication and reduced exercise capacity. This study investigated to what extent vasoactive enzymes might contribute to altered blood flow in PAD (Fontaine stage II). We compared femoral artery blood flow during reactive hyperaemia, leg-extension exercise and passive leg movement, and determined the level of vasoactive enzymes in skeletal muscle s les from the vastus lateralis in PAD (n = 10, 68.5 ± 6.5 years) and healthy controls (CON, n = 9, 62.1 ± 12.3 years). Leg blood flow was measured with Doppler ultrasound and muscle protein levels of phosphorylated endothelial nitric oxide synthase, NADPH oxidase, cyclooxygenase 1 and 2, thromboxane synthase, and prostacyclin synthase were determined. Leg blood flow during the initial 90 s of passive leg movement (242 ± 33 vs 441 ± 75 ml min(-1), P = 0.03) and during reactive hyperaemia (423 ± 100 vs 1255 ± 175 ml min(-1), P = 0.002) was lower in PAD than CON, whereas no significant difference was observed for leg blood flow during exercise (1490 ± 250 vs 1887 ± 349 ml min(-1), P = 0.37). PAD had higher NADPH oxidase than CON (1.04 ± 0.19 vs 0.50 ± 0.06 AU, P = 0.02), with no differences for other enzymes. Leg blood flow during exercise was correlated with prostacyclin synthase (P = 0.001). Elevated NADPH oxidase indicates that oxidative stress may be a primary cause of low nitric oxide availability and impaired blood flow in PAD.
Publisher: Elsevier BV
Date: 05-2005
DOI: 10.1016/J.JVS.2005.01.037
Abstract: To better understand the association between skeletal muscle and exercise intolerance in peripheral arterial disease (PAD), we assessed treadmill-walking performance and gastrocnemius muscle phenotype in healthy control subjects and in patients with PAD. We hypothesized that gastrocnemius muscle characteristics would be altered in PAD compared with control subjects and that exercise tolerance in patients PAD would be related to muscle phenotype. Sixteen patients with PAD and intermittent claudication and 13 healthy controls of the same age participated. Each subject completed a graded treadmill-walking test and underwent a resting muscle biopsy. Muscle biopsy s les were obtained from the medial gastrocnemius muscle of the most ischemic limb in PAD and a limb chosen at random in controls. S les were analyzed for fiber type and cross-sectional area, capillary-to-fiber ratio, the number of capillaries in contact with each fiber type, and the optical density of glycogen within each fiber by using histochemical procedures. Total muscle glycogen content was determined biochemically. Exercise capacity measured on the incremental walking test in the PAD group was only 30% to 40% of that observed in controls. The PAD group had a lower proportion of type I muscle fibers (P < .05), fewer capillaries per muscle fiber (P < .05), and tended to have smaller fiber areas (P = .08). The relative area of type I fibers, the capillary-to-fiber ratio, capillary contacts with type I and IIa fibers, and the optical density of glycogen in type I fibers were all positively correlated with exercise tolerance in the PAD group (P < .05) but not controls. These data suggest that muscle phenotype is altered in PAD and that such alterations are associated with the exercise intolerance in these patients. In light of these findings, therapies such as resistance training or electrical stimulation that target skeletal muscle in PAD may prove beneficial, and further investigation of such therapies is warranted.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2019
DOI: 10.1519/JSC.0000000000002512
Abstract: Buzza, G, Lovell, GP, Askew, CD, and Solomon, C. The effect of short- and long-term aerobic training years on systemic O 2 utilization, and muscle and prefrontal cortex tissue oxygen extraction in young women. J Strength Cond Res 33(8): 2128–2137, 2019—This study aimed to determine if systemic O 2 utilization (V o 2 ) and tissue oxygen extraction (deoxyhemoglobin [HHb]) in the vastus lateralis (VL), gastrocnemius (GAST), and prefrontal cortex were different during exercise between short-term trained (STT, 6–24 months) and long-term trained (LTT, years) young women while controlling for current training load. Thirteen STT and 13 LTT participants completed r incremental (RI) and square-wave constant load (SWCL) tests on a cycle ergometer. In LTT compared with STT: (a) V o 2 was higher during the RI ( p = 0.024) and SWCL ( p = 0.001) tests (b) HHb in the VL ( p = 0.044) and GAST ( p = 0.027) was higher in the RI test and (c) there were significant group × intensity interactions for V o 2 in the SWCL test. The additional years of aerobic training in LTT compared with STT (LTT 7.1 ± 1.9 vs. STT 1.5 ± 0.4 years) resulted in higher V o 2 and HHb in the VL and GAST. These results indicate that in young women, independent of current training load, systemic V o 2 and peripheral muscle O 2 extraction during exercise continues to increase beyond 24 months of aerobic training.
Publisher: Informa UK Limited
Date: 07-2010
Publisher: Springer Science and Business Media LLC
Date: 20-01-2013
DOI: 10.1007/S00421-013-2588-9
Abstract: Assessing changes in brain activity under extreme conditions like weightlessness is a desirable, but difficult undertaking. Results from previous studies report specific changes in brain activity connected to an increase or decrease in gravity forces. Nevertheless, so far it remains unclear (1) whether this is connected to a redistribution of blood volume during micro- or hypergravity and (2) whether this redistribution might account for neurocognitive alterations. This study aimed to display changes in brain oxygenation caused by altered gravity conditions during parabolic flight. It was hypothesized that an increase in gravity would be accompanied by a decrease in brain oxygenation, whereas microgravity would lead to an increase in brain oxygenation. Oxygenized and deoxygenized haemoglobin were measured using two near infrared spectroscopy (NIRS) probes on the left and right prefrontal cortex throughout ten parabolas in nine subjects. Results show a decrease of 1.44 μmol/l in oxygenized haemoglobin with the onset of hypergravity, followed by a considerable increase during microgravity (up to 5.34 μmol/l). In contrast, deoxygenized haemoglobin was not altered during the first but only during the second hypergravity phase and showed only minor changes during microgravity. Changes in oxygenized and deoxygenized haemoglobin indicate an increase in arterial flow to the brain and a decrease in venous outflow during microgravity.
Publisher: Wiley
Date: 21-10-2020
DOI: 10.1113/EP089065
Publisher: Frontiers Media SA
Date: 15-03-2018
Publisher: Public Library of Science (PLoS)
Date: 10-11-2016
Publisher: MDPI AG
Date: 26-04-2019
DOI: 10.3390/NU11050954
Abstract: Aging is often associated with reduced leg blood flow, increased arterial stiffness, and endothelial dysfunction, all of which are related to declining nitric oxide (NO) bioavailability. Flow mediated dilatation (FMD) and passive leg movement (PLM) hyperaemia are two techniques used to measure NO-dependent vascular function. We hypothesised that acute dietary nitrate (NO3−) supplementation would improve NO bioavailability, leg FMD, and PLM hyperaemia. Fifteen healthy older men (69 ± 4 years) attended two experiment sessions and consumed either 140 mL of concentrated beetroot juice (800 mg NO3−) or placebo (NO3−-depleted beetroot juice) in a randomised, double blind, cross-over design study. Plasma nitrite (NO2−) and NO3−, blood pressure (BP), augmentation index (AIx75), pulse wave velocity (PWV), FMD of the superficial femoral artery, and PLM hyperaemia were measured immediately before and 2.5 h after consuming NO3− and placebo. Placebo had no effect but NO3− led to an 8.6-fold increase in plasma NO2−, which was accompanied by an increase in FMD (NO3−: +1.18 ± 0.94% vs. placebo: 0.23 ± 1.13%, p = 0.002), and a reduction in AIx75 (NO3−: −8.7 ± 11.6% vs. placebo: −4.6 ± 5.5%, p = 0.027). PLM hyperaemia, BP, and PWV were unchanged during both trials. This study showed that a dose of dietary NO3− improved NO bioavailability and enhanced endothelial function as measured by femoral artery FMD. These findings provide insight into the specific central and peripheral vascular responses to dietary NO3− supplementation in older adults.
Publisher: Wiley
Date: 29-06-2019
DOI: 10.1111/CPF.12537
Abstract: Short-term changes in arterial stiffness with exercise are proposed to better reflect vascular impairments than resting measures alone and are suggested as a prognostic indicator of cardiovascular risk in older adults. Arterial stiffness indices are reliable at rest, but the time-course and reliability of postexercise changes in arterial stiffness in older adults are unknown. The precision of postexercise changes in arterial stiffness should be determined prior to their use in large prospective trials. This study assessed the between-day reliability of the changes in pulse wave velocity (PWV), augmentation index (AIx75) and reflection magnitude (RM) following an exercise bout in older adults. Ten older adults (71 ± 5 years) were tested on three separate days, 7 days apart. PWV, AIx75 and RM were assessed at rest, immediately post and at 20, 40 and 60 min during recovery after moderate-intensity cycling. Intraclass correlation coefficient (ICC) and reliability coefficient (RC) were used to assess the relative and absolute reliability of arterial stiffness responses. PWV increased, and RM decreased immediately after exercise (P<0·05), and returned to baseline during recovery. AIx decreased during recovery (P<0·001). Resting ICC values were 0·91 (PWV), 0·72 (AIx75) and 0·40 (RM). Reliability of the immediate changes following exercise was high for PWV (ICC:0·87, RC:1·9 m s
Publisher: Wiley
Date: 10-05-2021
DOI: 10.1113/EP089424
Abstract: What is the topic of this review? We have conducted a systematic review and meta‐analysis on the current evidence for the effect of heat therapy on blood pressure and vascular function. What advances does it highlight? We found that heat therapy reduced mean arterial, systolic and diastolic blood pressure. We also observed that heat therapy improved vascular function, as assessed via brachial artery flow‐mediated dilatation. Our results suggest that heat therapy is a promising therapeutic tool that should be optimized further, via mode and dose, for the prevention and treatment of cardiovascular disease risk factors. Lifelong sauna exposure is associated with reduced cardiovascular disease risk. Recent studies have investigated the effect of heat therapy on markers of cardiovascular health. We aimed to conduct a systematic review with meta‐analysis to determine the effects of heat therapy on blood pressure and indices of vascular function in healthy and clinical populations. Four databases were searched up to September 2020 for studies investigating heat therapy on outcomes including blood pressure and vascular function. Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to assess the certainty of evidence. A total of 4522 titles were screened, and 15 studies were included. Healthy and clinical populations were included. Heat exposure was for 30–90 min, over 10–36 sessions. Compared with control conditions, heat therapy reduced mean arterial pressure [ n = 4 studies mean difference (MD): −5.86 mmHg, 95% confidence interval (CI): −8.63, −3.10 P 0.0001], systolic blood pressure ( n = 10 MD: −3.94 mmHg, 95% CI: −7.22, −0.67 P = 0.02) and diastolic blood pressure ( n = 9 MD: −3.88 mmHg, 95% CI: −6.13, −1.63 P = 0.0007) and improved flow‐mediated dilatation ( n = 5 MD: 1.95%, 95% CI: 0.14, 3.76 P = 0.03). Resting heart rate was unchanged ( n = 10 MD: −1.25 beats/min 95% CI: −3.20, 0.70 P = 0.21). Early evidence also suggests benefits for arterial stiffness and cutaneous microvascular function. The certainty of evidence was moderate for the effect of heat therapy on systolic and diastolic blood pressure and heart rate and low for the effect of heat therapy on mean arterial pressure and flow‐mediated dilatation. Heat therapy is an effective therapeutic tool to reduce blood pressure and improve macrovascular function. Future research should aim to optimize heat therapy, including the mode and dose, for the prevention and management of cardiovascular disease.
Publisher: Springer Science and Business Media LLC
Date: 25-03-2014
DOI: 10.1007/S40279-014-0173-Y
Abstract: Exercise can be prescribed to prevent, manage, and treat many leading non-communicable diseases (NCDs) and underlying risk factors. However, surprisingly, Australia is one of only a few countries where allied healthcare professionals with specialized university education and training in exercise prescription and delivery provide services within a government-run healthcare system (Medicare). This article presents data on Medicare-funded services provided by accredited exercise physiologists (AEPs) from the inclusion of the profession in the allied healthcare model (January, 2006) to the end of 2012. We conceptualize these data in relation to current NCD trends, and outline recommendations that can potentially help curtail the current chronic disease burden through the further integration of exercise professionals into the healthcare system in Australia, and internationally. From 2006 to 2012, the number of AEPs in Australia has increased 563 %. This rise in AEPs has been paralleled by increased delivery of services for eligible patients with a chronic medical condition (+614 %), type 2 diabetes mellitus (+211 to 230 %), and of Aboriginal and Torres Strait Islander descent (+343 %). These trends, which were developed through the "early years" of the profession, are encouraging and suggest that AEPs have taken up a vital position within the healthcare system. However, the total number of services provided by AEPs currently remains very low in relation to the prevalence of overweight-obesity and type 2 diabetes in Australia. Furthermore, services for Aboriginal Australians are very low considering the extreme burden of chronic diseases in these vulnerable populations. We provide some recommendations that may help the exercise physiology profession play a greater role in tackling the NCD burden and shift the healthcare model in a direction that is more proactive and focused on disease prevention and health, including the early identification and treatment of major upstream risk factors.
Publisher: Human Kinetics
Date: 2017
Abstract: The use of cold-water immersion (CWI) for postexercise recovery has become increasingly prevalent in recent years, but there is a dearth of strong scientific evidence to support the optimization of protocols for performance benefits. While the increase in practice and popularity of CWI has led to multiple studies and reviews in the area of water immersion, the research has predominantly focused on performance outcomes associated with postexercise CWI. Studies to date have generally shown positive results with enhanced recovery of performance. However, there are a small number of studies that have shown CWI to have either no effect or a detrimental effect on the recovery of performance. The rationale for such contradictory responses has received little attention but may be related to nuances associated with in iduals that may need to be accounted for in optimizing prescription of protocols. To recommend optimal protocols to enhance athletic recovery, research must provide a greater understanding of the physiology underpinning performance change and the factors that may contribute to the varied responses currently observed. This review focuses specifically on why some of the current literature may show variability and disparity in the effectiveness of CWI for recovery of athletic performance by examining the body temperature and cardiovascular responses underpinning CWI and how they are related to performance benefits. This review also examines how in idual characteristics (such as physique traits), differences in water-immersion protocol (depth, duration, temperature), and exercise type (endurance vs maximal) interact with these mechanisms.
Publisher: American Physiological Society
Date: 07-2018
Publisher: Springer Science and Business Media LLC
Date: 12-10-2016
DOI: 10.1007/S40279-016-0635-5
Abstract: Both revascularisation and supervised exercise training improve functional outcomes and quality of life in patients with peripheral arterial disease (PAD). However, the value of combined therapy, where exercise therapy is delivered as an adjunct to revascularisation, is less clear. To systematically review evidence on the efficacy of lower limb revascularisation combined with supervised exercise training in patients with PAD. Parallel-group randomised controlled trials indexed in the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, Embase, Scopus, CINAHL, SPORTDiscus and Web of Science were searched (up to Jan 2016). Outcome measures were pain-free and maximum walking distances, ankle-brachial index (ABI), leg blood flow and quality of life. Methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) scale. Eight trials were included that enrolled a total of 726 patients (mean age 66 ± 3 years, ABI 0.66 ± 0.05). Combined therapy led to greater improvements in pain-free (mean difference [MD] range 38-408 m) and maximal walking distances (MD range 82-321 m) compared with revascularisation or supervised training alone. Combined therapy had no added effect on resting ABI over revascularisation (MD range -0.05 to 0.13), and had a significantly greater effect than supervised exercise training alone (MD range 0.13-0.31). Limited evidence (one to three trials) also suggested that combined therapy led to greater improvements in leg blood flow and physical domains of quality of life than supervised exercise training alone, and that improvements in leg blood flow, as well as the physical and mental domains of quality of life were not different to that achieved with revascularisation alone. Current evidence suggests that PAD patients treated with combined therapy achieve greater functional benefits than those treated with revascularisation or supervised exercise training alone. Limited evidence also suggests that the effect of combined therapy on leg haemodynamics and quality of life may be superior to supervised exercise training alone, and similar to revascularisation alone.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.NEUROSCIENCE.2019.09.035
Abstract: Evidence suggests that cerebrovascular hemodynamic disturbances underlie cognitive deterioration secondary to cardiovascular disease (CVD), including manifestations other than stroke, but the mechanisms remain unclear. To date, the majority of studies have used neuropsychological measures validated for the detection of clinically significant cognitive decline but lack the sensitivity to accurately detect subclinical or subtle cognitive changes. The N2 and P3 components of the event-related potential are sensitive markers of attention and cognitive processing, and are valuable in the assessment of age-related cognitive changes and neurodegenerative disease. The aims of this study were to test (a) the sensitivity of N2 and P3 components in differentiating older adults with CVD from healthy controls, and (b) whether cerebrovascular hemodynamics are associated with alterations in attention in persons with non-stroke CVD. Older adults with CVD (n = 20) and healthy older adults (n = 20) without cognitive impairment or history of stroke and matched for age, were recruited. Cerebral blood flow velocity of the middle cerebral artery (MCAv) and Gosling's Pulsatility Index (PI) were assessed using Transcranial Doppler ultrasound (TCD). ERPs were elicited using a two-tone auditory oddball task. N2 litude was significantly reduced in the CVD group at midline frontal, central and parietal sites (p 0.6). No significant group differences were observed in N2 latency, P3 litude, or P3 latency. Further, MCAv and PI were strongly associated with N2 litude in the CVD group, such that greater MCAv was associated with reductions in N2 litude (b = -0.58, p = .018), whilst PI was associated with increases in N2 litude (b = 0.66, p = .006). No relationships between MCAv or PI with N2 or P3 ERP components were observed in the healthy control group. The data reported here suggest that a reduction in N2 litude may be an important objective indicator of subclinical cognitive and attentional alterations in non-stroke CVD, and support the notion that cerebrovascular hemodynamic disturbances play a role in the pathogenesis of cognitive deterioration secondary to non-stroke CVD.
Publisher: Springer Science and Business Media LLC
Date: 12-2009
Abstract: It has been proposed that adenosine triphosphate (ATP) released from red blood cells (RBCs) may contribute to the tight coupling between blood flow and oxygen demand in contracting skeletal muscle. To determine whether ATP may contribute to the vasodilatory response to exercise in the forearm, we measured arterialised and venous plasma ATP concentration and venous oxygen content in 10 healthy young males at rest, and at 30 and 180 seconds during dynamic handgrip exercise at 45% of maximum voluntary contraction (MVC). Venous plasma ATP concentration was elevated above rest after 30 seconds of exercise (P 0.05), and remained at this higher level 180 seconds into exercise (P 0.05 versus rest). The increase in ATP was mirrored by a decrease in venous oxygen content. While there was no significant relationship between ATP concentration and venous oxygen content at 30 seconds of exercise, they were moderately and inversely correlated at 180 seconds of exercise (r = -0.651, P = 0.021). Arterial ATP concentration remained unchanged throughout exercise, resulting in an increase in the venous-arterial ATP difference. Collectively these results indicate that ATP in the plasma originated from the muscle microcirculation, and are consistent with the notion that deoxygenation of the blood perfusing the muscle acts as a stimulus for ATP release. That ATP concentration was elevated just 30 seconds after the onset of exercise also suggests that ATP may be a contributing factor to the blood flow response in the transition from rest to steady state exercise.
Publisher: Public Library of Science (PLoS)
Date: 27-09-2016
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2017
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2001
DOI: 10.1097/00005768-200109000-00001
Abstract: Supplementation with propionyl-L-carnitine (PLC) may be of use in improving the exercise capacity of people with peripheral arterial disease. After a 2-wk exercise familiarization phase, seven subjects displaying intermittent claudication were studied over a 12-wk period consisting of three 4-wk phases, baseline (B), supplementation (S), and placebo (P). PLC was supplemented at 2 g x d(-1), and subjects were blinded to the order of supplementation. Unilateral calf strength and endurance were assessed weekly. Walking performance was assessed at the end of each phase using an incremental protocol, during which respiratory gases were collected. Although there was not a significant increase in maximal walking time ( approximately 14%) in the whole group, walking time improved to a greater extent than the in idual baseline coefficient of variation in four of the seven subjects. The changes in walking performance were correlated with changes in the respiratory exchange ratio both at steady state (r = 0.59) and maximal exercise (r = 0.79). Muscle strength increased significantly from 695 +/- 198 N to 812 +/- 249 N by the end of S. Changes in calf strength from B to S were modestly related to changes in walking performance (r = 0.56). No improvements in calf endurance were detected throughout the study. These preliminary data suggest that, in addition to walking performance, muscle strength can be increased in PAD patients after 4 wk of supplementation with propionyl-L-carnitine.
Publisher: MDPI AG
Date: 20-06-2021
DOI: 10.3390/BIOMEDICINES9060699
Abstract: The endothelium is the single-cell monolayer that lines the entire vasculature. The endothelium has a barrier function to separate blood from organs and tissues but also has an increasingly appreciated role in anti-coagulation, vascular senescence, endocrine secretion, suppression of inflammation and beyond. In modern times, endothelial cells have been identified as the source of major endocrine and vaso-regulatory factors principally the dissolved lipophilic vosodilating gas, nitric oxide and the potent vascular constricting G protein receptor agonists, the peptide endothelin. The role of the endothelium can be conveniently conceptualized. Continued investigations of the mechanism of endothelial dysfunction will lead to novel therapies for cardiovascular disease. In this review, we discuss the impact of endothelial dysfunction on cardiovascular disease and assess the clinical relevance of endothelial dysfunction.
Publisher: Elsevier BV
Date: 2006
Publisher: American Physiological Society
Date: 15-12-2013
DOI: 10.1152/JAPPLPHYSIOL.00979.2013
Abstract: Peripheral arterial disease (PAD) is caused by atherosclerosis and is associated with microcirculatory impairments in skeletal muscle. The present study evaluated the angiogenic response to exercise and passive movement in skeletal muscle of PAD patients compared with healthy control subjects. Twenty-one PAD patients and 17 aged control subjects were randomly assigned to either a passive movement or an active exercise study. Interstitial fluid microdialysate and tissue s les were obtained from the thigh skeletal muscle. Muscle dialysate vascular endothelial growth factor (VEGF) levels were modestly increased in response to either passive movement or active exercise in both subject groups. The basal muscle dialysate level of the angiostatic factor thrombospondin-1 protein was markedly higher ( P 0.05) in PAD patients compared with the control subjects, whereas soluble VEGF receptor-1 dialysate levels were similar in the two groups. The basal VEGF protein content in the muscle tissue s les was ∼27% lower ( P 0.05) in the PAD patients compared with the control subjects. Analysis of mRNA expression for a range of angiogenic and angiostatic factors revealed a modest change with active exercise and passive movement in both groups, except for an increase ( P 0.05) in the ratio of angiopoietin-2 to angiopoietin-1 mRNA in the PAD group with both interventions. PAD patients and aged in iduals showed a similar limited angiogenic response to active exercise and passive movement. The limited increase in muscle extracellular VEGF combined with an elevated basal level of thrombospondin-1 in muscle extracellular fluid of PAD patients may restrict capillary growth in these patients.
Publisher: American Physiological Society
Date: 15-05-2016
DOI: 10.1152/AJPREGU.00480.2015
Abstract: Intermittent claudication (IC) is the most commonly reported symptom of peripheral arterial disease (PAD). Impaired limb blood flow is a major casual factor of lower exercise tolerance in PAD but cannot entirely explain it. We hypothesized that IC is associated with structural changes of the capillary-mitochondria interface that could contribute to the reduction of exercise tolerance in IC patients. Capillary and mitochondrial morphometry were performed after light and transmission electron microscopy using vastus lateralis muscle biopsies of 14 IC patients and 10 age-matched controls, and peak power output (PPO) was determined for all participants using an incremental single-leg knee-extension protocol. Capillary density was lower (411 ± 90 mm −2 vs. 506 ± 95 mm −2 P ≤ 0.05) in the biopsies of the IC patients than in those of the controls. The basement membrane (BM) around capillaries was thicker (543 ± 82 nm vs. 423 ± 97 nm P ≤ 0.01) and the volume density of mitochondria was lower (3.51 ± 0.56% vs. 4.60 ± 0.74% P ≤ 0.01) in the IC patients than the controls. In the IC patients, a higher proportion of capillaries appeared with collapsed slit-like lumen and/or swollen endothelium. PPO was lower (18.5 ± 9.9 W vs. 33.5 ± 9.4 W P ≤ 0.01) in the IC patients than the controls. We suggest that several structural alterations in skeletal muscle, either collectively or separately, contribute to the reduction of exercise tolerance in IC patients.
Publisher: Public Library of Science (PLoS)
Date: 16-05-2019
Publisher: Elsevier BV
Date: 10-2008
DOI: 10.1016/J.NEUROIMAGE.2008.06.010
Abstract: Basic changes in environmental conditions are fundamental to understanding brain cortical mechanisms. Several studies have reported impairment of central nervous processes during weightlessness. There is ongoing debate as to whether these impairments are attributable to primary physiological effects or secondary psychological effects of the weightlessness environment. This study evaluates the physiological effects of changed gravity conditions on brain cortical activity. In a first experiment, EEG activity of seven participants was recorded at normal, increased and zero gravity during a parabolic flight. Additionally an EEG under normal gravity conditions preflight was recorded. In a second experiment, 24 participants were exposed to a supine, seated and 9 degree head-down tilt position while EEG was recorded. Data were analysed using low resolution brain electromagnetic tomography (LORETA). Beta-2 EEG activity (18-35 Hz) was found to be increased in the right superior frontal gyrus under normal gravity conditions inflight. By exposure to weightlessness a distinct inhibition of this activity within the same areas could be noticed. As the tilt experiment showed changes in the left inferior temporal gyrus in supine and tilted positions we conclude that the observed changes under weightlessness are not explainable by hemodynamic changes but rather reflect emotional processes related to the experience of weightlessness. These findings suggest that weightlessness has a major impact on electro cortical activity and may affect central nervous and adaptation processes.
Publisher: Elsevier BV
Date: 11-2019
DOI: 10.1016/J.EJVS.2019.02.021
Abstract: Elevated arterial stiffness is a characteristic of abdominal aortic aneurysm (AAA), and is associated with AAA growth and cardiovascular mortality. A bout of exercise transiently reduces aortic and systemic arterial stiffness in healthy adults. Whether the same response occurs in patients with AAA is unknown. The effect of moderate- and higher intensity exercise on arterial stiffness was assessed in patients with AAA and healthy adults. Twenty-two men with small diameter AAAs (36 ± 5 mm mean age 74 ± 6 years) and 22 healthy adults (mean age 72 ± 5 years) were included. Aortic stiffness was measured using carotid to femoral pulse wave velocity (PWV), and systemic arterial stiffness was estimated from the wave reflection magnitude (RM) and augmentation index (Alx75). Measurements were performed at rest and during 90 min of recovery following three separate test sessions in a randomised order: (i) moderate intensity continuous exercise (ii) higher intensity interval exercise or (iii) seated rest. At rest, PWV was higher in patients with AAA than in healthy adults (p < .001), while AIx75 and RM were similar between groups. No differences were observed between AAA patients and healthy adults in post-exercise aortic and systemic arterial stiffness after either exercise protocol. When assessed as the change from baseline (delta, Δ), post-exercise ΔAIx75 was not different to the seated rest protocol. Conversely, post-exercise ΔPWV and ΔRM were both lower at all time points than seated rest (p < .001). ΔPWV was lower immediately after higher intensity than after moderate intensity exercise (p = .015). High resting aortic stiffness in patients with AAA is not exacerbated after exercise. There was a similar post-exercise attenuation in arterial stiffness between patients with AAA and healthy adults compared with seated rest. This effect was most pronounced following higher intensity interval exercise, suggesting that this form of exercise may be a safe and effective adjunctive therapy for patients with small AAAs.
Publisher: Elsevier BV
Date: 04-2009
Publisher: Springer Science and Business Media LLC
Date: 10-09-2019
DOI: 10.1038/S41598-019-49362-Z
Abstract: Abdominal aortic aneurysm (AAA) is associated with inflammation and oxidative stress, the latter of which contributes to activation of macrophages, a prominent cell type in AAA. Omega-3 polyunsaturated fatty acids (n-3 PUFAs) have been reported to limit oxidative stress in animal models of AAA. The aim of this study was to evaluate the effect of the n-3 PUFA docosahexaenoic acid (DHA) on antioxidant defence in macrophages from patients with AAA. Cells were obtained from men with small AAA (diameter 3.0–4.5 cm, 75 ± 6 yr, n = 19) and age- matched male controls (72 ± 5 yr, n = 41) and incubated with DHA for 1 h before exposure to 0.1 µg/mL lipopolysaccharide (LPS) for 24 h. DHA supplementation decreased the concentration of tumour necrosis factor-α (TNF-α control, 42.1 ± 13.6 to 5.1 ± 2.1 pg/ml, p 0.01 AAA, 25.2 ± 9.8 to 1.9 ± 0.9 pg/ml, p 0.01) and interleukin-6 (IL-6 control, 44.9 ± 7.7 to 5.9 ± 2.0 pg/ml, p 0.001 AAA, 24.3 ± 5.2 to 0.5 ± 0.3 pg/ml, p 0.001) in macrophage supernatants. DHA increased glutathione peroxidase activity (control, 3.2 ± 0.3 to 4.1 ± 0.2 nmol/min/ml/μg protein, p = 0.004 AAA, 2.3 ± 0.5 to 3.4 ± 0.5 nmol/min/ml/μg protein, p = 0.008) and heme oxygenase-1 mRNA expression (control, 1.5-fold increase, p 0.001). The improvements in macrophage oxidative stress status serve as a stimulus for further investigation of DHA in patients with AAA.
Publisher: Wiley
Date: 05-2002
DOI: 10.1046/J.1475-097X.2002.00423.X
Abstract: This study tested the hypotheses that skeletal muscle mitochondrial ATP production rate (MAPR) is impaired in patients with peripheral arterial disease (PAD) and that it relates positively to their walking performances. Seven untrained patients, eight exercise-trained patients and 11 healthy controls completed a maximal walking test and had muscle s led from the gastrocnemius medialis muscle. Muscle was analysed for its MAPR in the presence of pyruvate, palmitoyl-L-carnitine or both, as well as citrate synthase (CS) activity. MAPRs were not different between untrained PAD and controls. In contrast, MAPRs (pyruvate) were significantly higher in trained PAD vs. controls. MAPR (pyruvate combinations) was also significantly higher in trained than untrained PAD muscle. MAPR and CS activity were highly correlated with walking performance in patients, but not in controls. These data do not support the hypothesis that isolated mitochondria are functionally impaired in PAD and demonstrate that the muscle mitochondrial capacity to oxidize carbohydrate is positively related to walking performance in these patients.
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.PHYSBEH.2009.01.007
Abstract: An increasing number of studies within the recent years connected physical exercise with changes in brain cortical activity. Most of this data (1) refers to aerobic exercise and (2) does not correlate to psychological parameters although it is well known that exercise has a positive effect on mood. In times where health activities play a major role it is increasingly necessary to connect somato-physiological and somatopsychological components of physical activity. This study aimed to find changes in EEG activity and mood after low, preferred and high intensity running. EEG and actual state of mood were recorded before and after exercise. Results showed an effect for the preferred and high intensity velocity in both, EEG and mood. As only the higher frequency areas N18 Hz showed persisting decreases post-exercise we concluded that this might be a sign of outlasting effects of exercise on brain cortical activity which may have influences on general well-being. We could also show that there is a clear relationship between EEG activity and mood reflecting a basic principle of cortical excitation.
Publisher: Springer Science and Business Media LLC
Date: 30-08-2017
DOI: 10.1007/S11065-017-9359-Z
Abstract: Cardiovascular disease is associated with increased risk for cognitive decline and dementia, but it is unclear whether this risk varies across disease states or occurs in the absence of symptomatic stroke. To examine the evidence of increased risk for cognitive decline and dementia following non-stroke cardiovascular disease we conducted two independent meta-analyses in accordance with PRISMA guidelines. The first review examined cardiovascular diagnoses (atrial fibrillation, congestive heart failure, periphery artery disease and myocardial infarction) while the second review assessed the impact of atherosclerotic burden (as indicated by degree of stenosis, calcification score, plaque morphology or number of plaques). Studies eligible for review longitudinally assessed risk for clinically significant cognitive decline and/or dementia and excluded stroke and cognitive impairment at baseline. Summary statistics were computed via the inverse variance weighted method, utilising Cox Proportional Hazards data (Hazard Ratios, HR). Both atrial fibrillation (n = 5, HR = 1.26, 95% CI [1.12, 1.43]) and severe atherosclerosis (n = 4, HR = 1.59, 95% CI [1.12, 2.26]) emerged as significant risk factors for cognitive decline and/or dementia. A small set of studies reviewed, insufficient for meta-analysis, examining congestive heart failure, peripheral artery disease and myocardial infarction suggested that these conditions may also be associated with an increased risk of cognitive decline/dementia. In the absence of stroke, patients with atrial fibrillation or generalised atherosclerosis are at heightened risk for cognitive deterioration. Nonetheless, this paper highlights the need for methodologically rigorous and prospective investigation of the relationship between CVD and dementia.
Publisher: American Physiological Society
Date: 02-2019
Publisher: Wiley
Date: 09-2002
DOI: 10.1046/J.1475-097X.2002.00442.X
Abstract: To shed light on the potential efficacy of cycling as a testing modality in the treatment of intermittent claudication (IC), this study compared physiological and symptomatic responses to graded walking and cycling tests in claudicants. Sixteen subjects with peripheral arterial disease (resting ankle: brachial index (ABI) < 0.9) and IC completed a maximal graded treadmill walking (T) and cycle (C) test after three familiarization tests on each mode. During each test, symptoms, oxygen uptake (VO2), minute ventilation (VE), respiratory exchange ratio (RER) and heart rate (HR) were measured, and for 10 min after each test the brachial and ankle systolic pressures were recorded. All but one subject experienced calf pain as the primary limiting symptom during T whereas the symptoms were more varied during C and included thigh pain, calf pain and dyspnoea. Although maximal exercise time was significantly longer on C than T (690 +/- 67 vs. 495 +/- 57 s), peak VO2, peak VE and peak heart rate during C and T were not different whereas peak RER was higher during C. These responses during C and T were also positively correlated (P < 0.05) with each other, with the exception of RER. The postexercise systolic pressures were also not different between C and T. However, the peak decline in ankle pressures from resting values after C and T were not correlated with each other. These data demonstrate that cycling and walking induce a similar level of metabolic and cardiovascular strain, but that the primary limiting symptoms and haemodynamic response in an in idual's extremity, measured after exercise, can differ substantially between these two modes.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 14-02-2019
DOI: 10.1249/MSS.0000000000001924
Abstract: Aging is associated with impaired cerebral blood flow (CBF) and increased risk of cerebrovascular disease. Acute increases in CBF during exercise may initiate improvements in cerebrovascular health, but the CBF response is diminished during continuous exercise in older adults. The effect of interval exercise for promoting increases in CBF in young and old adults is unknown. We compared middle cerebral artery blood velocity (MCAv), end-tidal CO 2 (P ET CO 2 ) and blood pressure (mean arterial pressure [MAP]) during intensity- and work-matched bouts of continuous (10-min 60% W max , followed by 10-min rest) and interval cycling (10 × 1-min 60% W max , separated by 1-min rest) in 11 young (25 ± 3 yr) and 10 old (69 ± 3 yr) men. Middle cerebral artery velocity was higher during continuous compared with interval exercise in the young ( P 0.001), but not in the old. This trend was also seen for changes in P ET CO 2 . Although absolute MAP was higher in the old, the relative rise (%∆) in MAP was similar between age groups and was greater during continuous exercise than interval. When we assessed the total accumulated change in MCAv (area under curve: exercise + recovery), it was higher with interval compared with continuous exercise in both groups ( P = 0.018). These findings suggest that interval exercise may be an effective alternative for promoting acute increases in CBF velocity, particularly in those older adults who may have difficulty sustaining continuous exercise.
Publisher: Springer Science and Business Media LLC
Date: 08-01-2023
DOI: 10.1186/S40798-022-00539-3
Abstract: The COVID-19 pandemic markedly changed how healthcare services are delivered and telehealth delivery has increased worldwide. Whether changes in healthcare delivery borne from the COVID-19 pandemic impact effectiveness is unknown. Therefore, we examined the effectiveness of exercise physiology services provided during the COVID-19 pandemic. This prospective cohort study included 138 clients who received exercise physiology services during the initial COVID-19 pandemic. Outcome measures of interest were EQ-5D-5L, EQ-VAS, patient-specific functional scale, numeric pain rating scale and goal attainment scaling. Most (59%, n = 82) clients received in-person delivery only, whereas 8% ( n = 11) received telehealth delivery only and 33% ( n = 45) received a combination of delivery modes. Mean (SD) treatment duration was 11 (7) weeks and included 12 (6) sessions lasting 48 (9) minutes. The majority (73%, n = 101) of clients completed 80% of exercise sessions. Exercise physiology improved mobility by 14% ( β = 0.23, P = 0.003), capacity to complete usual activities by 18% ( β = 0.29, P 0.001), capacity to complete important activities that the client was unable to do or having difficulty performing by 54% ( β = 2.46, P 0.001), current pain intensity by 16% ( β = − 0.55, P = 0.038) and goal attainment scaling t-scores by 50% ( β = 18.37, P 0.001). Effectiveness did not differ between delivery modes (all: P 0.087). Exercise physiology services provided during the COVID-19 pandemic improved a range of client-reported outcomes regardless of delivery mode. Further exploration of cost-effectiveness is warranted.
Publisher: Elsevier BV
Date: 11-2014
DOI: 10.1016/J.JSAMS.2013.10.251
Abstract: Peripheral arterial disease (PAD) is characterised by atherosclerotic stenosis or occlusion of the arteries of the lower limbs, resulting in an impairment of blood flow to the legs. Patients with PAD have a significant reduction in their physical capacity and are limited during activities such as walking by intermittent claudication. Position stand. Synthesis of published work within the field of exercise training and peripheral arterial disease. Supervised exercise training is considered the most effective treatment for increasing exercise tolerance in patients with PAD, and is also associated with improvements in daily physical activity and quality of life, and a reduction is cardiovascular disease risk. Exercise should be prescribed and progressed for patients in idually, taking into consideration their disease severity, exercise tolerance and relevant comorbidities. While walking programs are beneficial and frequently prescribed, other forms of aerobic exercise such as cycling or arm-cranking may also be incorporated as tolerated by patients. Forty minutes of accumulated aerobic activity, three times per week, is recommended for most patients. Patients should be encouraged to commence exercise at a moderate intensity, and should stop and rest if claudication pain becomes severe. Resistance training should also be included on at least two days per week with the goal of improving muscular strength and endurance. Comorbidities such as musculoskeletal complaints, hypertension, diabetes and peripheral neuropathy are common in patients with PAD and may exacerbate their functional limitations. Given the high cardiovascular risk associated with PAD, it is important that patients are appropriately monitored during exercise.
Publisher: Springer Science and Business Media LLC
Date: 20-01-2007
DOI: 10.1007/S00125-006-0587-7
Abstract: There are conflicting data about the effect of type 2 diabetes mellitus on exercise tolerance in peripheral arterial disease. To elucidate this problem, we compared the tolerance and physiological responses to treadmill and cycle exercise in 31 patients with peripheral arterial disease and intermittent claudication. One group of these patients had type 2 diabetes (n = 12) and its members were matched for sex and age with a group of patients who did not have diabetes (n = 12). Since BMI and body weight were greater in the diabetic group (28.4 +/- 3.7 vs 25.2 +/- 2.4 kg/m(2) 84.0 +/- 14.6 vs 73.8 +/- 8.0 kg), we also studied a third, 'heavy' group of non-diabetic patients with claudication of similar age (n = 7 BMI = 30.9 +/- 5.3 kg/m(2) body weight = 85.2 +/- 8.2 kg). Compared with the 'light' non-diabetic group, maximum treadmill times were shorter for the diabetic and heavy non-diabetic groups (1,448 vs 845 and 915 s ANOVA p = 0.01) maximum cycle time also tended to be shorter (ANOVA, p = 0.08) in the diabetic and heavy non-diabetic groups (median = 1,231 vs 730 and 797 s). The majority of physiological responses assessed were not different between the groups, although the time constant of oxygen uptake during submaximal treadmill and cycle exercise was significantly larger (ANOVA p < 0.05) for the diabetic group. These data demonstrate that exercise tolerance is lower in diabetic than non-diabetic patients with claudication, but that this difference is due to obesity rather than diabetes itself.
Publisher: American Physiological Society
Date: 07-2021
DOI: 10.1152/AJPHEART.00880.2020
Abstract: We address two aims: Aim 1 (Fitness Review) compares the effect of higher cardiorespiratory fitness (CRF) (e.g., endurance athletes) with lower CRF (e.g., sedentary adults) on cerebrovascular outcomes, including middle cerebral artery velocity (MCAv), cerebrovascular reactivity and resistance, and global cerebral blood flow, as assessed by transcranial Doppler (TCD) or magnetic resonance imaging (MRI). Aim 2 (Exercise Training Review) determines the effect of exercise training on cerebrovascular outcomes. Systematic review of studies with meta-analyses where appropriate. Certainty of evidence was assessed by the Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Twenty studies (18 using TCD) met the eligibility criteria for Aim 1, and 14 studies (8 by TCD) were included for Aim 2. There was a significant effect of higher CRF compared with lower CRF on cerebrovascular resistance (effect size = −0.54, 95% confidence interval = −0.91 to −0.16) and cerebrovascular reactivity (0.98, 0.41–1.55). Studies including males only demonstrated a greater effect of higher CRF on cerebrovascular resistance than mixed or female studies (male only: −0.69, −1.06 to −0.32 mixed and female studies: 0.10, −0.28 to 0.49). Exercise training did not increase MCAv (0.05, −0.21 to 0.31) but showed a small nonsignificant improvement in cerebrovascular reactivity (0.60, −0.08 to 1.28 P = 0.09). Exercise training showed heterogeneous effects on regional but little effect on global cerebral blood flow as measured by MRI. High CRF positively effects cerebrovascular function, including decreased cerebrovascular resistance and increased cerebrovascular reactivity however, global cerebral blood flow and MCAv are primarily unchanged following an exercise intervention in healthy and clinical populations.
Publisher: American Medical Association (AMA)
Date: 06-02-2013
Abstract: Approximately one-third of patients with peripheral artery disease experience intermittent claudication, with consequent loss of quality of life. To determine the efficacy of ramipril for improving walking ability, patient-perceived walking performance, and quality of life in patients with claudication. Randomized, double-blind, placebo-controlled trial conducted among 212 patients with peripheral artery disease (mean age, 65.5 [SD, 6.2] years), initiated in May 2008 and completed in August 2011 and conducted at 3 hospitals in Australia. Patients were randomized to receive 10 mg/d of ramipril (n = 106) or matching placebo (n = 106) for 24 weeks. Maximum and pain-free walking times were recorded during a standard treadmill test. The Walking Impairment Questionnaire (WIQ) and Short-Form 36 Health Survey (SF-36) were used to assess walking ability and quality of life, respectively. At 6 months, relative to placebo, ramipril was associated with a 75-second (95% CI, 60-89 seconds) increase in mean pain-free walking time (P < .001) and a 255-second (95% CI, 215-295 seconds) increase in maximum walking time (P < .001). Relative to placebo, ramipril improved the WIQ median distance score by 13.8 (Hodges-Lehmann 95% CI, 12.2-15.5), speed score by 13.3 (95% CI, 11.9-15.2), and stair climbing score by 25.2 (95% CI, 25.1-29.4) (P < .001 for all). The overall SF-36 median Physical Component Summary score improved by 8.2 (Hodges-Lehmann 95% CI, 3.6-11.4 P = .02) in the ramipril group relative to placebo. Ramipril did not affect the overall SF-36 median Mental Component Summary score. Among patients with intermittent claudication, 24-week treatment with ramipril resulted in significant increases in pain-free and maximum treadmill walking times compared with placebo. This was associated with a significant increase in the physical functioning component of the SF-36 score. clinicaltrials.gov Identifier: NCT00681226.
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.JELEKIN.2014.10.019
Abstract: Maximum force (Fmax) declines during intermittent submaximal contractions, but the linearity of this fatigue response and number of underlying phases is not clear. Healthy men were studied during two experiments (n=10 each). Experiment 1 involved single bouts of intermittent forearm contractions (50% Fmax) to failure using both limbs assigned as Armcontrol or Armtraining. Experiment 2 involved five bouts of intermittent calf contractions (60% Fmax) to failure using the same limb where data from the longest single trial (Calfsingle) or averaged across five bouts (Calfaveraged) were analysed. Fmax was assessed at 25-30s intervals during exercise and fitted to ten mono- and biphasic functions consisting of linear and/or nonlinear terms. For each fatigue response, the function which provided the best fit was determined on statistical grounds. Biphasic functions provided the majority of best fits during Armcontrol (9/10), Armtraining (10/10), Calfsingle (7/10) and Calfaveraged (9/10). For each condition, linear functions provided the best fit in 4-5 out of 10 responses. Two biphasic functions differentiated only by their first term (linear versus exponential) provided the best fit for 29/40 fatigue responses. These outcomes suggest that fatigue during intermittent contractions exhibits a biphasic response characterised by nonlinear and linear behaviour.
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.JSAMS.2009.08.004
Abstract: Running gait has been shown to alter due to changes in intensity. It was hypothesised that a sacral mounted single inertial sensor could identify the centre of mass (COM) vertical accelerations. This study aimed to validate this new technique against a criterion measure and to determine the influence of changes in running intensity on COM vertical acceleration and the symmetry of COM vertical acceleration between left and right steps. Ten athletes ran for 5min at their self-selected pace, plus 1km/h above and below this velocity. Validity of the single inertial sensor was determined by comparing COM vertical acceleration against that measured with a six-camera infrared system. Large correlation (r=0.96), a small typical error of estimate (1.84), and mean bias (0.02) were found between the two systems. The greatest magnitude in COM vertical acceleration occurred at the slowest running pace and decreased as pace increased. Sixty percent of the athletes exhibited asymmetry during at least one running pace 30% were asymmetrical across all three velocities. While significant changes in COM vertical acceleration occurred between the different running velocities, this did not always result in a change in symmetry. This study found that a single inertial sensor can be used as a valid means of measuring COM vertical acceleration. This technique can detect changes in the COM vertical acceleration that may change with running velocity. Gait symmetry (using COM vertical acceleration) during running was also quantified using the inertial sensor.
Publisher: Springer Science and Business Media LLC
Date: 30-05-2018
DOI: 10.1007/S00421-018-3900-5
Abstract: Increased arterial stiffness is observed with ageing and in in iduals with low cardiorespiratory fitness ([Formula: see text]O Fifty-one older adults (72 ± 5 years) were stratified into fitness tertiles ([Formula: see text]O After control, delta PWV increased over time (P < 0.001) and delta RM was unchanged. After higher-intensity interval exercise, delta PWV (P < 0.001) and delta RM (P < 0.001) were lower to control in all fitness groups. After moderate-intensity continuous exercise, delta PWV was not different from control in low-fit adults (P = 0.057), but was lower in the mid- and higher-fit older adults. Post-exercise AIx75 was higher to control in all fitness groups (P = 0.001). In older adults, PWV increases during seated rest and this response is attenuated after higher-intensity interval exercise, regardless of fitness level. This attenuation was also observed after moderate-intensity continuous exercise in adults with higher, but not lower fitness levels. Submaximal exercise reveals differences in the arterial stiffness responses between older adults with higher and lower cardiorespiratory fitness.
Publisher: PeerJ
Date: 19-06-2018
DOI: 10.7717/PEERJ.5026
Abstract: High-intensity interval training (HIIT) has been proposed as a time-efficient exercise format to improve exercise adherence, thereby targeting the chronic disease burden associated with sedentary behaviour. Exercise mode (cycling, running), if self-selected, will likely affect the physiological and enjoyment responses to HIIT in sedentary in iduals. Differences in physiological and enjoyment responses, associated with the mode of exercise, could potentially influence the uptake and continued adherence to HIIT. It was hypothesised that in young sedentary men, local and systemic oxygen utilisation and enjoyment would be higher during a session of running HIIT, compared to a session of cycling HIIT. A total of 12 sedentary men (mean ± SD age 24 ± 3 years) completed three exercise sessions: a maximal incremental exercise test on a treadmill (MAX) followed by two experiment conditions, (1) free-paced cycling HIIT on a bicycle ergometer (HIITCYC) and (2) constant-paced running HIIT on a treadmill ergometer (HIITRUN). Deoxygenated haemoglobin (HHb) in the gastrocnemius (GN), the left vastus lateralis (LVL) and the right vastus lateralis (RVL) muscles, oxygen consumption (VO 2 ), heart rate (HR), ratings of perceived exertion (RPE) and physical activity enjoyment (PACES) were measured during HIITCYC and HIITRUN. There was a higher HHb in the LVL ( p = 0.001) and RVL ( p = 0.002) sites and a higher VO 2 ( p = 0.017) and HR ( p 0.001) during HIITCYC, compared to HIITRUN. RPE was higher ( p 0.001) and PACES lower ( p = 0.032) during HIITCYC compared to HIITRUN. In sedentary in iduals, free-paced cycling HIIT produces higher levels of physiological stress when compared to constant-paced running HIIT. Participants perceived running HIIT to be more enjoyable than cycling HIIT. These findings have implications for selection of mode of HIIT for physical stress, exercise enjoyment and compliance.
Publisher: Elsevier BV
Date: 11-2007
DOI: 10.1016/J.CLINBIOCHEM.2007.07.022
Abstract: Compare different protocols for blood processing to be used during parabolic flights. Measurement of cortisol (COR), prolactin (PRL), adrenocorticotropic hormone (ACTH), epinephrine (EP) and norepinephrine (NOR) concentrations stored at different temperatures and intervals before analysis. COR, PRL and NOR showed no changes in concentration between analysis protocols. ACTH dropped by 60% when not analysed within 24 h. A standardised processing protocol that includes a 4-h delay following blood collection is suitable for the assessment of serum stress hormone concentrations.
Publisher: Informa UK Limited
Date: 13-07-2018
DOI: 10.1080/02640414.2017.1355062
Abstract: This study examined the influence of body composition on temperature and blood flow responses to post-exercise cold water immersion (CWI), hot water immersion (HWI) and control (CON). Twenty-seven male participants were stratified into three groups: 1) low mass and low fat (LM-LF) 2) high mass and low fat (HM-LF) or 3) high mass and high fat (HM-HF). Experimental trials involved a standardised bout of cycling, maintained until core temperature reached 38.5°C. Participants subsequently completed one of three 15-min recovery interventions (CWI, HWI, or CON). Core, skin and muscle temperatures, and limb blood flow were recorded at baseline, post-exercise, and every 30 min following recovery for 240 min. During CON and HWI there were no differences in core or muscle temperature between body composition groups. The rate of fall in core temperature following CWI was greater in the LM-LF (0.03 ± 0.01°C/min) group compared to the HM-HF (0.01 ± 0.001°C/min) group (P = 0.002). Muscle temperature decreased to a greater extent during CWI in the LM-LF and HM-LF groups (8.6 ± 3.0°C) compared with HM-HF (5.1 ± 2.0°C, P < 0.05). Blood flow responses did not differ between groups. Differences in body composition alter the thermal response to post-exercise CWI, which may explain some of the variance in the responses to CWI recovery.
Publisher: MDPI AG
Date: 31-12-2020
DOI: 10.3390/NU13010138
Abstract: Abdominal aortic aneurysm (AAA) is a vascular disease involving permanent focal dilation of the abdominal aorta (≥30 mm) that can lead to catastrophic rupture. Destructive remodeling of aortic connective tissue in AAA contributes to wall stiffening, a mechanical parameter of the arterial system linked to a heightened risk of cardiovascular morbidity and mortality. Since aortic stiffening is associated with AAA progression, treatment options that target vascular inflammation would appear prudent. Given this, and growing evidence indicating robust anti-inflammatory and vasoprotective properties for long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs), this study evaluated the impact of these nutrients (1.8 g/day for 12 weeks) on indices of vascular stiffness in patients with AAA. At baseline, pulse wave velocity (PWV) and augmentation index normalized to a heart rate of 75 bpm (AIx75) were significantly higher in patients with AAA compared to control participants (PWV: 14.2 ± 0.4 m.s−1 vs. 12.6 ± 0.4 m.s−1, p = 0.014 AIx75: 26.4 ± 1.7% vs. 17.3 ± 2.7%, p = 0.005). Twelve-week LC n-3 PUFA supplementation significantly decreased PWV (baseline: 14.2 ± 0.6 m.s−1, week 12: 12.8 ± 0.7 m.s−1, p = 0.014) and heart rate (baseline: 63 ± 3 bpm, week 12: 58 ± 3 bpm, p = 0.009) in patients with AAA. No change was observed for patients receiving placebo capsules. While this raises the possibility that LC n-3 PUFAs provide improvements in aortic stiffness in patients with AAA, the clinical implications remain to be fully elucidated.
Publisher: Human Kinetics
Date: 03-2018
Abstract: Purpose : To explore the influence of body composition on thermal responses to cold-water immersion (CWI) and the recovery of exercise performance. Methods : Male subjects were stratified into 2 groups: low fat (LF n = 10) or high fat (HF n = 10). Subjects completed a high-intensity interval test (HIIT) on a cycle ergometer followed by a 15-min recovery intervention (control [CON] or CWI). Core temperature (T c ), skin temperature, and heart rate were recorded continuously. Performance was assessed at baseline, immediately post-HIIT, and 40 min postrecovery using a 4-min cycling time trial (TT), countermovement jump (CMJ), and isometric midthigh pull (IMTP). Perceptual measures (thermal sensation [TS], total quality of recovery [TQR], soreness, and fatigue) were also assessed. Results : T c and TS were significantly lower in LF than in HF from 10 min (T c, LF 36.5°C ± 0.5°C, HF 37.2°C ± 0.6°C TS, LF 2.3 ± 0.5 arbitrary units [a.u.], HF 3.0 ± 0.7 a.u.) to 40 min (T c , LF 36.1°C ± 0.6°C, HF 36.8°C ±0.7°C TS, LF 2.3 ± 0.6 a.u., HF 3.2 ± 0.7 a.u.) after CWI ( P .05). Recovery of TT performance was significantly enhanced after CWI in HF (10.3 ± 6.1%) compared with LF (3.1 ± 5.6%, P = .01) however, no differences were observed between HF (6.9% ±5.7%) and LF (5.4% ± 5.2%) with CON. No significant differences were observed between groups for CMJ, IMTP, TQR, soreness, or fatigue in either condition. Conclusion : Body composition influences the magnitude of T c change during and after CWI. In addition, CWI enhanced performance recovery in the HF group only. Therefore, body composition should be considered when planning CWI protocols to avoid overcooling and maximize performance recovery.
Publisher: Informa UK Limited
Date: 19-06-2019
DOI: 10.1080/17461391.2019.1629632
Abstract: In rehabilitation settings, exercise intensity is often monitored with Borg's rating of perceived exertion (RPE). However, previous studies showed that severe cognitive impairment may limit the usability of the RPE. The aim of this study was to assess the relationship between RPE and heart rate (HR), and to establish whether a target RPE can be used to achieve exercise intensity based on an in idual's HR-RPE in people with early cognitive impairment. 97 participants (74.7 ± 6 years) with early cognitive impairment completed an incremental exercise test. Of these, 54 were tested during a single, RPE guided exercise session. RPE and HR were monitored throughout. Correlations between HR and RPE were assessed using Spearman's correlation. Mean differences between measured HR and target HR were calculated and compared using a two-way ANOVA with factors cognition and exercise mode. Bland-Altman plots were constructed to analyse the agreement between target and measured HR. HR and RPE correlated moderately with each other (
Publisher: American Physiological Society
Date: 07-2018
Publisher: Informa UK Limited
Date: 2009
DOI: 10.1080/10253890802499175
Abstract: Previous findings of decreased mental and perceptual motor performance during parabolic flights have been attributed mainly to the primary effects of weightlessness rather than the accompanying effects of stress and altered mood. Although recent studies have alluded to the possible negative effects of stress on performance, there has been no attempt to investigate this during parabolic flights. Over a period of 3 years, 27 human participants (male n = 18, mean age +/- SD 34.67 +/- 7.59 years female n = 9, 36.22 +/- 9.92 years) were recruited with the aim to evaluate if, and to what extent, parabolic flights are accompanied by changes in mood. Furthermore, the relationships between mood and physiological markers of stress and arousal, namely circulating stress hormones (ACTH, cortisol, epinephrine, norepinephrine, prolactin and brain activity (EEG)) were investigated. A strong and significant correlation was found between circulating stress hormone concentrations and perceived physical state, motivational state (MOT) and psychological strain (PSYCHO), whereas no interaction between mood and EEG or EEG and stress hormone concentrations was observed. Therefore, two different stress responses appear to be present during parabolic flight. The first seems to be characterised by general cortical arousal, whereas the second seems to evolve from the adrenomedullary system. It is likely that both these mechanisms have different effects on mental and perceptual motor performance, which require further investigation and should to be taken into account when interpreting previous weightlessness research.
Publisher: MDPI AG
Date: 04-02-2022
Abstract: Physical activity (PA) participation was substantially reduced at the start of the COVID-19 pandemic. The purpose of this study was to assess the association between PA, mental health, and wellbeing during and following the easing of COVID-19 restrictions in the United Kingdom (UK) and New Zealand (NZ). In this study, 3363 adults completed online surveys within 2–6 weeks of initial COVID-19 restrictions (April/May 2020) and once restrictions to human movement had been eased. Outcome measures included the International Physical Activity Questionnaire Short-Form, Depression Anxiety and Stress Scale-9 (mental health) and World Health Organisation-5 Wellbeing Index. There were no differences in PA, mental health or wellbeing between timepoints (p 0.05). In iduals engaging in moderate or high volume of PA had significantly better mental health (−1.1 and −1.7 units, respectively) and wellbeing (11.4 and 18.6 units, respectively) than in iduals who engaged in low PA (p 0.001). Mental health was better once COVID-19 restrictions were eased (p 0.001). NZ had better mental health and wellbeing than the UK (p 0.001). Participation in moderate-to-high volumes of PA was associated with better mental health and wellbeing, both during and following periods of COVID-19 containment, compared to participation in low volumes of PA. Where applicable, during the current or future pandemic(s), moderate-to-high volumes of PA should be encouraged.
Publisher: Informa UK Limited
Date: 10-2010
DOI: 10.1080/02640414.2010.507252
Abstract: The frequency for movements along the longitudinal axis during running peaks at approximately 3 Hz. Other physiological systems (e.g. heart rate and brain cortical activity) are known to show a dominant frequency of ~3 Hz connected to exercise. As recent studies have proposed a clear correlation between musical tempo, mood, and performance output, we wished to ascertain whether peak locomotion frequency of ~3 Hz during running is synchronized with different intrinsic and extrinsic frequencies. Eighteen healthy regular runners performed three outdoor running sessions at different intensities. Oscillations along the longitudinal axis were recorded using an accelerometer (ActiBelt). Electrocortical activity was recorded using electroencephalography before and after exercise and analysed in the delta frequency range (2-4 Hz). In addition, the frequency spectra of the participants' favourite musical pieces were analysed. Data revealed a peak frequency at around 2.7 to 2.8 Hz for the vertical acceleration during running. Similar oscillation patterns were found for heart rate and musical pieces. Electroencephalographic delta activity increased after running. Results of this study give reason to speculate that a strong relationship exists between intrinsic and extrinsic oscillation patterns during exercise. A frequency of approximately 3 Hz seems to be dominant in different physiological systems and seems to be rated as pleasurable when choosing the appropriate music for exercising. This is in line with previous research showing that an adequate choice of music during exercise enhances performance output and mood.
Publisher: JMIR Publications Inc.
Date: 08-02-2023
DOI: 10.2196/46370
Publisher: Elsevier BV
Date: 2009
DOI: 10.1016/J.PHYSBEH.2008.09.002
Abstract: Acute exercise has been shown to exhibit different effects on human sensorimotor behavior however, the causes and mechanisms of the responses are often not clear. The primary aim of the present study was to determine the effects of incremental running until exhaustion on sensorimotor performance and adaptation in a tracking task. Subjects were randomly assigned to a running group (RG), a tracking group (TG), or a running followed by tracking group (RTG), with 10 subjects assigned to each group. Treadmill running velocity was initially set at 2.0 m s(-1), increasing by 0.5 m s(-1) every 5 min until exhaustion. Tracking consisted of 35 episodes (each 40 s) where the subjects' task was to track a visual target on a computer screen while the visual feedback was veridical (performance) or left-right reversed (adaptation). Resting electroencephalographic (EEG) activity was recorded before and after each experimental condition (running, tracking, rest). Tracking performance and the final amount of adaptation did not differ between groups. However, task adaptation was significantly faster in RTG compared to TG. In addition, increased alpha and beta power were observed following tracking in TG but not RTG although exhaustive running failed to induce significant changes in these frequency bands. Our results suggest that exhaustive running can facilitate adaptation processes in a manual tracking task. Attenuated cortical activation following tracking in the exercise condition was interpreted to indicate cortical efficiency and exercise-induced facilitation of selective central processes during actual task demands.
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.PHYSBEH.2015.11.036
Abstract: There is increasing interest in the effects of microgravity on cognitive processing, particularly as it relates to the potential for human space travel. While findings to date are quite inconsistent, studies reporting a decrement in cognitive performance have generally not been able to distinguish between the direct influence of microgravity, and any associated influence of stress. Furthermore, the currently available findings are primarily based on behavioral observations, and there is a need to better understand the underlying neurophysiological responses. The current study aimed to determine the effects of microgravity on neurophysiological processing during a mental arithmetic task (executive function). During the normal- and microgravity phases of a parabolic flight, four levels of a mental arithmetic task were presented on a touchscreen tablet. The latency between the appearance of the problem and the participants' response was identified as reaction time. In addition visual evoked potentials N1 and P2 were determined using an active EEG system and analyzed using source localization algorithms. Results showed an increase in reaction time with increasing levels of task difficulty. During the most complex levels, reaction time was significantly reduced during microgravity. This observation was independent of previous parabolic flight experience as well as the use of anti-motion-sickness medication. P2 litude decrease during microgravity was concomitant to a related involvement of the superior frontal and medial frontal gyrus. It is concluded that cortical processes are enhanced during microgravity, and that previously reported impairments in cognitive performance are likely attributable to increased stress rather than weightlessness itself.
Publisher: Wiley
Date: 10-2020
DOI: 10.14814/PHY2.14580
Publisher: MDPI AG
Date: 21-09-2020
Abstract: Macrophages are implicated in the pathogenesis of abdominal aortic aneurysm (AAA). This study examined the environmentally conditioned responses of AAA macrophages to inflammatory stimuli. Plasma- and blood-derived monocytes were separated from the whole blood of patients with AAA (30–45 mm diameter n = 33) and sex-matched control participants (n = 44). Increased concentrations of pro-inflammatory and pro-oxidant biomarkers were detected in the plasma of AAA patients, consistent with systemic inflammation and oxidative stress. However, in monocyte-derived macrophages, a suppressed cytokine response was observed in AAA compared to the control following stimulation with lipopolysaccharide (LPS) (tumor necrosis factor alpha (TNF-α) 26.9 ± 3.3 vs. 15.5 ± 3.2 ng/mL, p 0.05 IL-6 3.2 ± 0.6 vs. 1.4 ± 0.3 ng/mL, p 0.01). LPS-stimulated production of 8-isoprostane, a biomarker of oxidative stress, was also markedly lower in AAA compared to control participants. These findings are consistent with developed tolerance in human AAA macrophages. As Toll-like receptor 4 (TLR4) has been implicated in tolerance, macrophages were examined for changes in TLR4 expression and distribution. Although TLR4 mRNA and protein expression were unaltered in AAA, cytosolic internalization of receptors and lipid rafts was found. These findings suggest the inflamed, pro-oxidant AAA microenvironment favors macrophages with an endotoxin-tolerant-like phenotype characterized by a diminished capacity to produce pro-inflammatory mediators that enhance the immune response.
Publisher: Portland Press Ltd.
Date: 14-11-2006
DOI: 10.1042/CS20060151
Abstract: Expansion of the capillary network, or angiogenesis, occurs following endurance training. This process, which is reliant on the presence of VEGF (vascular endothelial growth factor), is an adaptation to a chronic mismatch between oxygen demand and supply. Patients with IC (intermittent claudication) experience pain during exercise associated with an inadequate oxygen delivery to the muscles. Therefore the aims of the present study were to examine the plasma VEGF response to acute exercise, and to establish whether exercise training alters this response in patients with IC. In Part A, blood was collected from patients with IC (n=18) before and after (+20 and +60 min post-exercise) a maximal walking test to determine the plasma VEGF response to acute exercise. VEGF was present in the plasma of patients (45.11±29.96 pg/ml) and was unchanged in response to acute exercise. Part B was a training study to determine whether exercise training altered the VEGF response to acute exercise. Patients were randomly assigned to a treatment group (TMT n=7) that completed 6 weeks of high-intensity treadmill training, or to a control group (CON n=6). All patients completed a maximal walking test before and after the intervention, with blood s les drawn as for Part A. Training had no effect on plasma VEGF at rest or in response to acute exercise, despite a significant increase in maximal walking time in the TMT group (915±533 to 1206±500 s P=0.009) following the intervention. The absence of a change in plasma VEGF may reflect altered VEGF binding at the endothelium, although this cannot be confirmed by the present data.
Publisher: Wiley
Date: 05-2020
DOI: 10.14814/PHY2.14421
Publisher: American Physiological Society
Date: 2018
DOI: 10.1152/AJPHEART.00344.2017
Abstract: Endothelial dysfunction is observed in patients with abdominal aortic aneurysm (AAA), who have increased risk of cardiovascular events and mortality. This study aimed to assess the acute effects of moderate- and higher-intensity exercise on endothelial function, as assessed by flow-mediated dilation (FMD), in AAA patients (74 ± 6 yr old, n = 22) and healthy adults (72 ± 5 yr old, n = 22). Participants undertook three randomized visits, including moderate-intensity continuous exercise [40% peak power output (PPO)], higher-intensity interval exercise (70% PPO), and a no-exercise control. Brachial artery FMD was assessed at baseline and at 10 and 60 min after each condition. Baseline FMD was lower [by 1.10% (95% confidence interval: 0.72−.81), P = 0.044] in AAA patients than in healthy adults. There were no group differences in FMD responses after each condition ( P = 0.397). FMD did not change after no-exercise control but increased by 1.21% (95% confidence interval: 0.69−1.73, P 0.001) 10 min after moderate-intensity continuous exercise in both groups and returned to baseline after 60 min. Conversely, FMD decreased by 0.93% (95% confidence interval: 0.41−1.44, P 0.001) 10 min after higher-intensity interval exercise in both groups and remained decreased after 60 min. We found that the acute response of endothelial function to exercise is intensity-dependent and similar between AAA patients and healthy adults. Our findings provide evidence that regular exercise may improve vascular function in AAA patients, as it does in healthy adults. Improved FMD after moderate-intensity exercise may provide short-term benefit. Whether the decrease in FMD after higher-intensity exercise represents an additional risk and/or a greater stimulus for vascular adaptation remains to be elucidated. NEW & NOTEWORTHY Abdominal aortic aneurysm patients have vascular dysfunction. We observed a short-term increase in vascular function after moderate-intensity exercise. Conversely, higher-intensity exercise induced a prolonged reduction in vascular function, which may be associated with both short-term increases in cardiovascular risk and signaling for longer-term vascular adaptation in abdominal aortic aneurysm patients.
Publisher: American Medical Association (AMA)
Date: 13-10-2015
Publisher: Springer Science and Business Media LLC
Date: 12-02-2022
DOI: 10.1007/S40520-022-02079-Y
Abstract: Community-based exercise programs for older adults play a potentially important role in mitigating the decline in functional outcomes, body composition, psychosocial outcomes, and cardiovascular health outcomes that commonly occurs with advancing age. There is a limited understanding of the characteristics and effectiveness of community-based exercise programs, particularly when those programs are offered outside metropolitan areas. Rural/regional settings face unique challenges, such as limited access to equipment/resources, transportation, and services, as well as significant costs to run programs. The objective of this scoping review was to characterise studies in the field that have aimed to implement community-based programs in settings identified as rural / regional. A secondary aim was to establish guidance for future exercise programs in this setting and highlight future research directions. A total of 12 studies were conducted in settings identified as rural/regional areas in various countries across the world were included. Of the included studies, five were randomised controlled trials. The majority of included studies reported on functional outcomes (83%) and psychosocial outcomes (75%), yet only 42% reported body composition, 17% reported cardiovascular health and 17% reported dietary outcomes. Low male representation was observed, with women outnumbering men in 7 of 12 studies. There was also minimal investigation of qualitative outcomes in existing community-based exercise programs in rural/regional settings, presenting a key gap for future research to address. Study Protocol: osf.io/txpm3/ . Date of registration: 20 July 2020.
Publisher: MyJove Corporation
Date: 23-05-2011
DOI: 10.3791/2670
Publisher: Springer Science and Business Media LLC
Date: 09-03-2018
Publisher: PeerJ
Date: 07-06-2019
DOI: 10.7717/PEERJ.7077
Abstract: Sprint interval training (SIT) can be as effective, or more effective, than continuous moderate intensity exercise (CMIE) for improving a primary risk factor for cardiometabolic disease, low cardiorespiratory fitness (CRF). However, there has been no direct comparison in inactive in iduals, of the acute effects of a session of SIT with a work-matched session of CMIE on local oxygen utilisation, which is a primary stimulus for increasing CRF. Furthermore, post-exercise blood pressure (BP) and enjoyment, if symptomatic and low, respectively, have implications for safety and adherence to exercise and have not been compared between these specific conditions. It was hypothesised that in young inactive men, local oxygen utilisation would be higher, while post-exercise BP and enjoyment would be lower for SIT, when compared to CMIE. A total of 11 inactive men (mean ± SD age 23 ± 4 years) completed a maximal r -incremental exercise test followed by two experiment conditions: (1) SIT and (2) work-matched CMIE on a cycle ergometer on separate days. Deoxygenated haemoglobin (∆HHb) in the pre-frontal cortex (FH), gastrocnemius (GN), left vastus lateralis (LVL) and the right vastus lateralis (RVL) muscles, systemic oxygen utilisation (VO 2 ), systolic (SBP) and diastolic (DBP) blood pressure and physical activity enjoyment scale (PACES) were measured during the experiment conditions. During SIT, compared to CMIE, ∆HHb in FH ( p = 0.016) and GN ( p = 0.001) was higher, while PACES ( p = 0.032) and DBP ( p = 0.043) were lower. No differences in SBP and ∆HHb in LVL and RVL were found between conditions. In young inactive men, higher levels of physiological stress occurred during SIT, which potentially contributed to lower levels of post-exercise DBP and enjoyment, when compared to CMIE.
Publisher: Royal College of Physicians
Date: 03-2019
Publisher: American Physiological Society
Date: 05-2017
DOI: 10.1152/JAPPLPHYSIOL.00935.2016
Abstract: Impaired endothelial function is observed with aging and in those with low cardiorespiratory fitness (V̇o 2peak ). Improvements in endothelial function with exercise training are somewhat dependent on the intensity of exercise. While the acute stimulus for this improvement is not completely understood, it may, in part, be due to the flow-mediated dilation (FMD) response to acute exercise. We examined the hypothesis that exercise intensity alters the brachial (systemic) FMD response in elderly men and is modulated by V̇o 2peak . Forty-seven elderly men were stratified into lower (V̇o 2peak = 24.3 ± 2.9 ml·kg −1 ·min −1 n = 27) and higher fit groups (V̇o 2peak = 35.4 ± 5.5 ml·kg −1 ·min −1 n = 20) after a test of cycling peak power output (PPO). In randomized order, participants undertook moderate-intensity continuous exercise (MICE 40% PPO) or high-intensity interval cycling exercise (HIIE 70% PPO) or no-exercise control. Brachial FMD was assessed at rest and 10 and 60 min after exercise. FMD increased after MICE in both groups {increase of 0.86% [95% confidence interval (CI), 0.17–1.56], P = 0.01} and normalized after 60 min. In the lower fit group, FMD was reduced after HIIE [reduction of 0.85% (95% CI, 0.12–1.58), P = 0.02] and remained decreased at 60 min. In the higher fit group, FMD was unchanged immediately after HIIE and increased after 60 min [increase of 1.52% (95% CI, 0.41–2.62), P 0.01, which was correlated with V̇o 2peak , r = 0.41 P 0.01]. In the no-exercise control, FMD was reduced in both groups after 60 min ( P = 0.05). Exercise intensity alters the acute FMD response in elderly men and V̇o 2peak modulates the FMD response following HIIE but not MICE. The sustained decrease in FMD in the lower fit group following HIIE may represent a signal for vascular adaptation or endothelial fatigue. NEW & NOTEWORTHY This study is the first to show that moderate-intensity continuous cycling exercise increased flow-mediated dilation (FMD) transiently before normalization of FMD after 1 h, irrespective of cardiorespiratory fitness level in elderly men. Interestingly, we show increased FMD after high-intensity cycling exercise in higher fit men, with a sustained reduction in FMD in lower fit men. The prolonged reduction in FMD after high-intensity cycling exercise may be associated with future vascular adaptation but may also reflect a period of increased cardiovascular risk in lower fit elderly men.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-2010
Publisher: Elsevier BV
Date: 07-2006
DOI: 10.1016/J.JVS.2006.03.037
Abstract: To explore the efficacy of cycle training in the treatment of intermittent claudication, the present study compared performance and physiologic effects of cycle training with more conventional treadmill walking training in a group of patients with claudication. Forty-two in iduals with peripheral arterial disease and intermittent claudication (24 men, 18 women) were stratified by gender and the presence or absence of type 2 diabetes mellitus and then randomized to a treadmill (n = 13), cycle (n = 15), or control group (n = 14). Treadmill and cycle groups trained three times a week for 6 weeks, whereas the control group did not train during this period. Maximal and pain-free exercise times were measured on graded treadmill and cycle tests before and after training. Treadmill training significantly improved maximal and pain-free treadmill walking times but did not improve cycle performance. Cycle training significantly improved maximal cycle time but did not improve treadmill performance. However, there was evidence of a stronger cross-transfer effect between the training modes for patients who reported a common limiting symptom during cycling and walking at baseline. There was also considerable variation in the training response to cycling, and a subgroup of responsive patients in the cycle group improved their walking performance by more than the average response observed in the treadmill group. These findings suggest that cycle exercise is not effective in improving walking performance in all claudication patients but might be an effective alternative to walking in those who exhibit similar limiting symptoms during both types of exercise.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1194/JLR.P093013
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2018
Publisher: Elsevier BV
Date: 05-2011
DOI: 10.1016/J.NEUROSCIENCE.2011.02.006
Abstract: While the effects of exercise on brain cortical activity from pre-to post-exercise have been thoroughly evaluated, few studies have investigated the change in activity during exercise. As such, it is not clear to what extent changes in exercise intensity influence brain cortical activity. Furthermore, due to the difficulty in using brain-imaging methods during complex whole-body movements like cycling, it is unclear to what extent the activity in specific brain areas is altered with incremental exercise intensity over time. Latterly, active electroencephalography (EEG) electrodes combined with source localization methods allow for the assessment of brain activity, measured as EEG current density, within specific cortical regions. The present study aimed to investigate the application of this method during exercise on a cycle ergometer, and to investigate the effect of increasing exercise intensity on the magnitude and location of any changes in electrocortical current density. Subjects performed an incremental cycle ergometer test until subjective exhaustion. Current density of the EEG recordings during each test stage, as well as before and after exercise, was determined. Spatial changes in current density were localized using low-resolution brain electromagnetic tomography (LORETA) to three regions of interest the primary motor cortex, primary sensory cortex and prefrontal cortex, and were expressed relative to current density within the local lobe. It was demonstrated that the relative current density of the primary motor cortex was intensified with increasing exercise intensity, whereas activity of the primary sensory cortex and that of the prefrontal cortex were not altered with exercise. The results indicate that the combined active EEG/LORETA method allows for the recording of brain cortical activity during complex movements and incremental exercise. These findings indicate that primary motor cortex activity is elevated with incremental exercise intensity during a whole-body movement, like cycling.
Publisher: American Physiological Society
Date: 11-2018
DOI: 10.1152/AJPHEART.00232.2018
Abstract: Peripheral arterial disease (PAD) is characterized by stenosis and occlusion of the lower limb arteries. Although leg blood flow is limited in PAD, it remains unclear whether skeletal muscle microvascular perfusion is affected. We compared whole leg blood flow and calf muscle microvascular perfusion after cuff occlusion and submaximal leg exercise between patients with PAD ( n = 12, 69 ± 9 yr) and healthy age-matched control participants ( n = 12, 68 ± 7 yr). Microvascular blood flow (microvascular volume × flow velocity) of the medial gastrocnemius muscle was measured before and immediately after the following: 1) 5 min of thigh-cuff occlusion, and 2) a 5-min bout of intermittent isometric plantar-flexion exercise (400 N) using real-time contrast-enhanced ultrasound. Whole leg blood flow was measured after thigh-cuff occlusion and during submaximal plantar-flexion exercise using strain-gauge plethysmography. Postocclusion whole leg blood flow and calf muscle microvascular perfusion were lower in patients with PAD than control participants, and these parameters were strongly correlated ( r = 0.84, P 0.01). During submaximal exercise, total whole leg blood flow and vascular conductance were not different between groups. There were also no group differences in postexercise calf muscle microvascular perfusion, although microvascular blood volume was higher in patients with PAD than control participants (12.41 ± 6.98 vs. 6.34 ± 4.98 arbitrary units, P = 0.03). This study demonstrates that the impaired muscle perfusion of patients with PAD during postocclusion hyperemia is strongly correlated with disease severity and is likely mainly determined by the limited conduit artery flow. In response to submaximal leg exercise, microvascular flow volume was elevated in patients with PAD, which may reflect a compensatory mechanism to maintain muscle perfusion and oxygen delivery during recovery from exercise. NEW & NOTEWORTHY This study suggests that peripheral arterial disease (PAD) has different effects on the microvascular perfusion responses to cuff occlusion and submaximal leg exercise. Patients with PAD have impaired microvascular perfusion after cuff occlusion, similar to that previously reported after maximal exercise. In response to submaximal exercise, however, the microvascular flow volume response was elevated in patients with PAD compared with control. This finding may reflect a compensatory mechanism to maintain perfusion and oxygen delivery during recovery from exercise.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 05-2021
DOI: 10.1161/HYPERTENSIONAHA.120.15754
Abstract: Endothelial function, assessed using brachial artery flow-mediated dilation (FMD), predicts future cardiovascular disease (CVD) risk. This study established age- and sex-specific reference intervals for brachial artery FMD in healthy in iduals and examined the relation with CVD risk factors. In a retrospective study design, we pooled brachial artery FMD (acquired according to expert-consensus guidelines for FMD protocol and analysis) and participant characteristics/medical history from 5362 in iduals (4–84 years 2076 females). Healthy in iduals (n=1403 [582 females]) were used to generate age-/sex-specific percentile curves. Subsequently, we included in iduals with CVD risk factors, without overt disease (unmedicated n=3167 [1247 females] and medicated n=792 [247 females]). Multiple linear regression tested the relation of CVD risk factors (body mass index, blood pressure, cholesterol, diabetes, dyslipidemia, and smoking) with FMD. Healthy males showed a negative, curvilinear relation between FMD and age, while females revealed a negative linear relation that started higher but declined at a faster rate than males. Age- and sex-specific differences in FMD relate, at least partly, to baseline artery diameter. FMD was related to CVD risk factors in unmedicated (eg, systolic/diastolic blood pressure) and medicated in iduals (eg, diabetes/dyslipidemia). Sex mediated some of these effects ( P .05), with normalization of FMD in medicated men, but not women with dyslipidemia. In conclusion, sex alters the age-related decline in FMD, which may partly be explained through differences in baseline diameter. Sex also alters the influence of some CVD risk factors and medication on FMD. This work improves interpretation and future use of the FMD technique.
Publisher: Wiley
Date: 13-08-2012
Publisher: BMJ
Date: 16-03-2010
Abstract: The purpose of the present study was to compare the effects of cold water immersion (CWI) and active recovery (ACT) on resting limb blood flow, rectal temperature and repeated cycling performance in the heat. Ten subjects completed two testing sessions separated by 1 week each trial consisted of an initial all-out 35-min exercise bout, one of two 15-min recovery interventions (randomised: CWI or ACT), followed by a 40-min passive recovery period before repeating the 35-min exercise bout. Performance was measured as the change in total work completed during the exercise bouts. Resting limb blood flow, heart rate, rectal temperature and blood lactate were recorded throughout the testing sessions. There was a significant decline in performance after ACT (mean (SD) -1.81% (1.05%)) compared with CWI where performance remained unchanged (0.10% (0.71%)). Rectal temperature was reduced after CWI (36.8°C (1.0°C)) compared with ACT (38.3°C (0.4°C)), as was blood flow to the arms (CWI 3.64 (1.47) ml/100 ml/min ACT 16.85 (3.57) ml/100 ml/min) and legs (CW 4.83 (2.49) ml/100 ml/min ACT 4.83 (2.49) ml/100 ml/min). Leg blood flow at the end of the second exercise bout was not different between the active (15.25 (4.33) ml/100 ml/min) and cold trials (14.99 (4.96) ml/100 ml/min), whereas rectal temperature (CWI 38.1°C (0.3°C) ACT 38.8°C (0.2°C)) and arm blood flow (CWI 20.55 (3.78) ml/100 ml/min ACT 23.83 (5.32) ml/100 ml/min) remained depressed until the end of the cold trial. These findings indicate that CWI is an effective intervention for maintaining repeat cycling performance in the heat and this performance benefit is associated with alterations in core temperature and limb blood flow.
Publisher: AMPCo
Date: 07-2015
DOI: 10.5694/MJA14.01108
Publisher: Wiley
Date: 18-03-2022
DOI: 10.1113/EP089710
Abstract: What is the topic of this review? This review focuses on the physiological impact of abdominal aortic aneurysm (AAA) on cardiorespiratory fitness and the negative consequences of low fitness on clinical outcomes in AAA. We also discuss the efficacy of exercise training for improving cardiorespiratory fitness in AAA. What advances does it highlight? We demonstrate the negative impact of low fitness on disease progression and clinical outcomes in AAA. We highlight potential mechanistic determinants of low fitness in AAA and present evidence that exercise training can be an effective treatment strategy for improving cardiorespiratory fitness, postoperative mortality and disease progression. An abdominal aortic aneurysm (AAA) is an abnormal enlargement of the aorta, below the level of the renal arteries, where the aorta diameter increases by %. As an aneurysm increases in size, there is a progressive increase in the risk of rupture, which ranges from 25 to 40% for aneurysms .5 cm in diameter. People with AAA are also at a heightened risk of cardiovascular events and associated mortality. Cardiorespiratory fitness is impaired in people with AAA and is associated with poor (postoperative) clinical outcomes, including increased length of hospital stay and postoperative mortality after open surgical or endovascular AAA repair. Although cardiorespiratory fitness is a well‐recognized prognostic marker of cardiovascular health and mortality, it is not assessed routinely, nor is it included in current clinical practice guidelines for the management of people with AAA. In this review, we discuss the physiological impact of AAA on cardiorespiratory fitness, in addition to the consequences of low cardiorespiratory fitness on clinical outcomes in people with AAA. Finally, we summarize current evidence for the effect of exercise training interventions on cardiorespiratory fitness in people with AAA, including the associated improvements in postoperative mortality, AAA growth and cardiovascular risk. Based on this review, we propose that cardiorespiratory fitness should be considered as part of the routine risk assessment and monitoring of people with AAA and that targeting improvements in cardiorespiratory fitness with exercise training might represent a viable adjunct treatment strategy for reducing postoperative mortality and disease progression.
Publisher: Frontiers Media SA
Date: 23-11-2015
No related grants have been discovered for Christopher Askew.