ORCID Profile
0000-0002-7807-4144
Current Organisation
University of Adelaide
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Publisher: Wiley
Date: 10-07-2009
Publisher: Springer Science and Business Media LLC
Date: 12-03-2018
DOI: 10.1038/S41598-018-22491-7
Abstract: To optimise fecal s ling for reproducible analysis of the gut microbiome, we compared different methods of s le collection and sequencing of 16S rRNA genes at two centers. S les collected from six in iduals on three consecutive days were placed in commercial collection tubes (OMNIgeneGut OMR-200) or in sterile screw-top tubes in a home fridge or home freezer for 6–24 h, before transfer and storage at −80 °C. Replicate s les were shipped to centers in Australia and the USA for DNA extraction and sequencing by their respective PCR protocols, and analysed with the same bioinformatic pipeline. Variation in gut microbiome was dominated by differences between in iduals. Minor differences in the abundance of taxa were found between collection-processing methods and day of collection, and between the two centers. We conclude that collection with storage and transport at 4 °C within 24 h is adequate for 16S rRNA analysis of the gut microbiome. Other factors including differences in PCR and sequencing methods account for relatively minor variation compared to differences between in iduals.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2019
Publisher: Cambridge University Press (CUP)
Date: 21-11-2011
DOI: 10.1017/S0954422411000084
Abstract: Protein hydrolysates provide a rich source of protein which is useful in situations where excess protein is needed, such as during repair of tissue damage. The consumption of protein hydrolysates has been shown to result in more rapid uptake of amino acids compared with whole proteins or free-form amino acid mixtures and some peptides in hydrolysates exhibit biological activity. Early studies showed that protein hydrolysates are more effectively utilised than intact proteins or amino acids. In addition, they promote a strong insulinotropic effect, which reduces protein breakdown and enhances muscle and tissue uptake of branched-chain amino acids. These effects contribute to benefits of protein hydrolysates for enhancing repair of tissue damage caused by surgery, ulcers, burns and muscle-damaging exercise. While there is evidence that protein hydrolysates may be useful for facilitating tissue repair, additional research is needed to further examine various roles of protein hydrolysates in this process.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.JSAMS.2013.02.016
Abstract: Heart rate kinetics are faster in well-trained athletes at exercise onset, indicating sensitivity to training status, but whether they track performance changes due to changes in training load is unknown. Randomised, counterbalanced, cross-over. 17 cyclists completed two weeks of light and two weeks of heavy training. The day after each training period heart rate was recorded during 5 min cycling at 100 W to determine the maximal rate of heart rate increase. Participants then performed a 5 min cycle time-trial after which heart rate recovery was determined. Work during 5 min cycle time-trial decreased 3.5% (P<0.04) in participants (n=8) who increased training load (completed light training then heavy training) and, although maximal rate of heart rate increase did not change (P=0.27), within-in idual changes in work were correlated with changes in maximal rate of heart rate increase (r=0.87, P=0.005). Work during 5 min cycle time-trial increased 6.5% (P<0.001) in 9 participants who decreased training load (completed heavy training then light training) and maximal rate of heart rate increase increased 28% (P=0.002) but the changes in maximal work were not related to changes in rate of heart rate increase (r=0.32, P=0.40). Heart rate recovery tended to track changes in 5 min cycle time-trial work following increases and decreases in training load (r=0.65-0.75, P=0.03-0.08). Maximal rate of heart rate increases during cycling at 100 W tracks reductions in exercise performance when training load is increased, but not performance improvements when training loads are reduced. Maximal rate of heart rate increase may be a useful adjunct to heart rate recovery for tracking changes in exercise performance.
Publisher: Springer Science and Business Media LLC
Date: 09-03-2016
Publisher: Elsevier BV
Date: 05-2013
DOI: 10.1016/J.FERTNSTERT.2012.12.042
Abstract: To investigate the effect of undertaking lifestyle interventions during periods of seasonal change on vitamin D status and health outcomes in overweight/obese women with polycystic ovary syndrome (PCOS). Retrospective, unplanned secondary analysis of two cohorts during different seasons. Outpatient clinical research unit. Fifty overweight/obese women with PCOS. Twenty-week lifestyle modification program (Clinical Trials registration no.: ACTRN12606000198527) one cohort started in winter and finished in summer, and one started in summer and finished in winter. 25-Hydroxyvitamin D (25OH-D), weight, waist circumference (WC), body composition, cardiovascular disease (CVD) risk factors, and menstrual cycle length. Baseline 25OH-D levels were 27.6 ± 9.0 nmol/L. The winter cohort had lower 25OH-D levels at baseline, which increased over 20 weeks, whereas the summer cohort started with higher levels which decreased. Changes in 25OH-D were inversely correlated with changes in WC and cholesterol when controlling for baseline values, such that increases in 25OH-D were associated with greater reductions in WC and cholesterol. Obesity and CVD risk profiles improved in vitamin D-deficient women with PCOS after a 20-week lifestyle intervention during which vitamin D status improved with seasonal change. ACTRN12606000198527.
Publisher: Human Kinetics
Date: 07-2016
Abstract: Heart-rate variability (HRV) as a measure of autonomic function may increase in response to training interventions leading to increases or decreases in performance, making HRV interpretation difficult in isolation. This study aimed to contextualize changes in HRV with subjective measures of training tolerance. Supine and standing measures of vagally mediated HRV (root-mean-square difference of successive normal RR intervals [RMSSD]) and measures of training tolerance (Daily Analysis of Life Demands for Athletes questionnaire, perception of energy levels, fatigue, and muscle soreness) were recorded daily during 1 wk of light training (LT), 2 wk of heavy training (HT), and 10 d of tapering (T) in 15 male runners/triathletes. HRV and training tolerance were analyzed as rolling 7-d averages at LT, HT, and T. Performance was assessed after LT, HT, and T with a 5-km treadmill time trial (5TTT). Time to complete the 5TTT likely increased after HT (effect size [ES] ± 90% confidence interval = 0.16 ± 0.06) and then almost certainly decreased after T (ES = −0.34 ± 0.08). Training tolerance worsened after HT (ES ≥ 1.30 ± 0.41) and improved after T (ES ≥ 1.27 ± 0.49). Standing RMSSD very likely increased after HT (ES = 0.62 ± 0.26) and likely remained higher than LT at the completion of T (ES = 0.38 ± 0.21). Changes in supine RMSSD were possible or likely trivial. Vagally mediated HRV during standing increased in response to functional overreaching (indicating potential parasympathetic hyperactivity) and also to improvements in performance. Thus, additional measures such as training tolerance are required to interpret changes in vagally mediated HRV.
Publisher: Elsevier BV
Date: 12-2007
Publisher: AMPCo
Date: 11-2016
DOI: 10.5694/MJA16.00685
Publisher: MDPI AG
Date: 12-09-2021
Abstract: The effect of the menstrual cycle on athlete performance, wellbeing and perceived exertion and fatigue is not well understood. Furthermore, it has not been investigated specifically in Australian Football athletes. This pilot study aimed to explore how naturally menstruating Australian Football athletes may be affected by menstrual cycle phase. The data collected from the routine monitoring of five naturally menstruating athletes (average menstrual cycle length of 28 ± 3 [SD] days) in one team (athlete age range 18–35 years) competing in the Women’s Australian Football League during the 2019 season were retrospectively analysed to compare performance (countermovement jump parameters and adductor squeeze pressure), perceived exertion, perceived fatigue and wellbeing (perceived sleep quality, stress and soreness) outcomes between the follicular and luteal phases. Performance, perceived exertion, stress and soreness did not appear to be affected by menstrual cycle phase (p 0.17). However, perceived fatigue appeared to be significantly greater (p = 0.042) and sleep quality worse (p = 0.005) in the luteal phase. This pilot study suggests further research focusing on the effect of menstrual cycle phase on subjective fatigue and wellbeing is warranted.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2015
Publisher: Wiley
Date: 27-04-2011
Publisher: Human Kinetics
Date: 03-2017
Abstract: Stride-to-stride fluctuations in running-stride interval display long-range correlations that break down in the presence of fatigue accumulated during an exhaustive run. The purpose of the study was to investigate whether long-range correlations in running-stride interval were reduced by fatigue accumulated during prolonged exposure to a high training load (functional overreaching) and were associated with decrements in performance caused by functional overreaching. Ten trained male runners completed 7 d of light training (LT 7 ), 14 d of heavy training (HT 14 ) designed to induce a state of functional overreaching, and 10 d of light training (LT 10 ) in a fixed order. Running-stride intervals and 5-km time-trial (5TT) performance were assessed after each training phase. The strength of long-range correlations in running-stride interval was assessed at 3 speeds (8, 10.5, and 13 km/h) using detrended fluctuation analysis. Relative to performance post-LT 7 , time to complete the 5TT was increased after HT 14 (+18 s P .05) and decreased after LT 10 (–20 s P = .03), but stride-interval long-range correlations remained unchanged at HT 14 and LT 10 ( P .50). Changes in stride-interval long-range correlations measured at a 10.5-km/h running speed were negatively associated with changes in 5TT performance ( r –.46 P = .03). Runners who were most affected by the prolonged exposure to high training load (as evidenced by greater reductions in 5TT performance) experienced the greatest reductions in stride-interval long-range correlations. Measurement of stride-interval long-range correlations may be useful for monitoring the effect of high training loads on athlete performance.
Publisher: Frontiers Media SA
Date: 08-01-2021
DOI: 10.3389/FPHYS.2020.614765
Abstract: While post-exercise heart rate (HR) variability (HRV) has been shown to increase in response to training leading to improvements in performance, the effect of training leading to decrements in performance (i.e., overreaching) on this parameter has been largely ignored. This study evaluated the effect of heavy training leading to performance decrements on sub-maximal post-exercise HRV. Running performance [5 km treadmill time-trial (5TTT)], post-exercise HRV [root-mean-square difference of successive normal R-R intervals (RMSSD)] and measures of subjective training tolerance (Daily Analysis of Life Demands for Athletes “worse than normal” scores) were assessed in 11 male runners following 1 week of light training (LT), 2 weeks of heavy training (HT) and a 10 day taper (T). Post-exercise RMSSD was assessed following 5 min of running exercise at an in idualised speed eliciting 85% of peak HR. Time to complete 5TTT likely increased following HT ( ES = 0.14 ± 0.03 p & 0.001), and then almost certainly decreased following T ( ES = −0.30 ± 0.07 p & 0.001). Subjective training tolerance worsened after HT ( ES = −2.54 ± 0.62 p = 0.001) and improved after T ( ES = 2.16 ± 0.64 p = 0.004). In comparison to LT, post-exercise RMSSD likely increased at HT ( ES = 0.65 ± 0.55 p = 0.06), and likely decreased at T ( ES = −0.69 ± 0.45 p = 0.02). A moderate within-subject correlation was found between 5TTT and post-exercise RMSSD ( r = 0.47 ± 0.36 p = 0.03). Increased post-exercise RMSSD following HT demonstrated heightened post-exercise parasympathetic modulation in functionally overreached athletes. Heightened post-exercise RMSSD in this context appears paradoxical given this parameter also increases in response to improvements in performance. Thus, additional measures such as subjective training tolerance are required to interpret changes in post-exercise RMSSD.
Publisher: Hindawi Limited
Date: 07-01-2020
DOI: 10.1111/PEDI.12952
Abstract: Microbial exposures in utero and early life shape the infant microbiome, which can profoundly impact on health. Compared to the bacterial microbiome, very little is known about the virome. We set out to characterize longitudinal changes in the gut virome of healthy infants born to mothers with or without type 1 diabetes using comprehensive virome capture sequencing. Healthy infants were selected from Environmental Determinants of Islet Autoimmunity (ENDIA), a prospective cohort of Australian children with a first-degree relative with type 1 diabetes, followed from pregnancy. Fecal specimens were collected three-monthly in the first year of life. Among 25 infants (44% born to mothers with type 1 diabetes) at least one virus was detected in 65% (65/100) of s les and 96% (24/25) of infants during the first year of life. In total, 26 genera of viruses were identified and >150 viruses were differentially abundant between the gut of infants with a mother with type 1 diabetes vs without. Positivity for any virus was associated with maternal type 1 diabetes and older infant age. Enterovirus was associated with older infant age and maternal smoking. We demonstrate a distinct gut virome profile in infants of mothers with type 1 diabetes, which may influence health outcomes later in life. Higher prevalence and greater number of viruses observed compared to previous studies suggests significant underrepresentation in existing virome datasets, arising most likely from less sensitive techniques used in data acquisition.
Publisher: SAGE Publications
Date: 08-08-2017
Abstract: To investigate the reliability of a clinically applicable method of dynamometry to assess and monitor hip abductor muscle strength in older persons. Bilateral isometric hip abductor muscle strength measured with a handheld dynamometer, patients supine with the contralateral hip positioned directly against a wall for stabilization. Reliability determined by comparing intra-assessor and inter-assessor results and comparison to a criterion standard (stabilized dynamometer with patients in the standing position). UniSA Nutritional Physiology Research Centre. Twenty-one patients older than 65 years were recruited from the Royal Adelaide Hospital. Intraclass correlation coefficients (ICCs), bias, and limits of agreement calculated to determine reliability. Intra-assessor and inter-assessor ICCs were high (0.94 and 0.92-0.94, respectively). There was no intra-assessor bias and narrow limits of agreement (±2.4%). There was a small inter-assessor bias but narrow limits of agreement (0.6%-0.9% and ± 2.3%, respectively). There was a wide variation comparing results to the criterion standard (±5.0%-5.2% limits of agreement), highlighting problems attributed to difficulties that the test population had with the standing position used in the criterion standard test. Testing older persons’ hip abductor muscle strength while in the supine position with optimal pelvic stabilization using a handheld dynamometer is highly reliable. While further studies must be done to assess patients with specific pathologies, this test has potential application to monitor and evaluate the effects of surgical interventions and/or rehabilitation protocols for a variety of conditions affecting hip abductor function such as hip fractures and arthritis.
Publisher: American Diabetes Association
Date: 02-02-2022
DOI: 10.2337/DC21-2335
Abstract: Pregnancy and type 1 diabetes are each associated with increased anxiety and depression, but the combined impact on well-being is unresolved. We compared the mental health of women with and without type 1 diabetes during pregnancy and postpartum and examined the relationship between mental health and glycemic control. Participants were women enrolled from 2016 to 2020 in the Environmental Determinants of Islet Autoimmunity (ENDIA) study, a pregnancy to birth prospective cohort following children with a first-degree relative with type 1 diabetes. Edinburgh Postnatal Depression Scale (EPDS) and Perceived Stress Scale (PSS) were completed during the third trimester (T3) (median [interquartile range] 34 [32, 36] weeks) and postpartum (14 [13, 16] weeks) by 737 women (800 pregnancies) with (n = 518) and without (n = 282) type 1 diabetes. EPDS and PSS scores did not differ between women with and without type 1 diabetes during T3 and postpartum. EPDS scores were marginally higher in T3: predicted mean (95% CI) 5.7 (5.4, 6.1) than postpartum: 5.3 (5.0, 5.6), independent of type 1 diabetes status (P = 0.01). HbA1c levels in type 1 diabetes were 6.3% [5.8, 6.9%] in T3 and did not correlate with EPDS or PSS scores. Reported use of psychotropic medications was similar in women with (n = 44 of 518 [8%]) and without type 1 diabetes (n = 17 of 282 [6%]), as was their amount of physical activity. Overall, mental health in late pregnancy and postpartum did not differ between women with and without type 1 diabetes, and mental health scores were not correlated with glycemic control.
Publisher: Elsevier BV
Date: 2010
DOI: 10.1016/J.JSAMS.2008.06.007
Abstract: There is evidence that protein hydrolysates can speed tissue repair following damage and may therefore be useful for accelerating recovery from exercise induced muscle damage. The potential for a hydrolysate (WPI(HD)) of whey protein isolate (WPI) to speed recovery following eccentric exercise was evaluated by assessing effects on recovery of peak isometric torque (PIT). In a double-blind randomised parallel trial, 28 sedentary males had muscle soreness (MS), serum creatine kinase (CK) activity, plasma TNFalpha, and PIT assessed at baseline and after 100 maximal eccentric contractions (ECC) of their knee extensors. Participants then consumed 250 ml of flavoured water (FW n=11), or FW containing 25 g WPI (n=11) or 25 g WPI(HD) (n=6) and the assessments were repeated 1, 2, 6 and 24h later. PIT decreased approximately 23% following ECC, remained suppressed in FW and WPI, but recovered fully in WPI(HD) by 6h (P=0.006, treatment x time interaction). MS increased following ECC (P 0.45). WPI(HD) may be a useful supplement for assisting athletes to recover from fatiguing eccentric exercise.
Publisher: MDPI AG
Date: 03-03-2014
DOI: 10.3390/NU6030974
Publisher: Springer Science and Business Media LLC
Date: 18-02-2016
DOI: 10.1007/S40279-016-0484-2
Abstract: Autonomic regulation of heart rate (HR) as an indicator of the body's ability to adapt to an exercise stimulus has been evaluated in many studies through HR variability (HRV) and post-exercise HR recovery (HRR). Recently, HR acceleration has also been investigated. The aim of this systematic literature review and meta-analysis was to evaluate the effect of negative adaptations to endurance training (i.e., a period of overreaching leading to attenuated performance) and positive adaptations (i.e., training leading to improved performance) on autonomic HR regulation in endurance-trained athletes. We searched Ovid MEDLINE, Embase, CINAHL, SPORTDiscus, PubMed, and Academic Search Premier databases from inception until April 2015. Included articles examined the effects of endurance training leading to increased or decreased exercise performance on four measures of autonomic HR regulation: resting and post-exercise HRV [vagal-related indices of the root-mean-square difference of successive normal R-R intervals (RMSSD), high frequency power (HFP) and the standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) only], and post-exercise HRR and HR acceleration. Of the 5377 records retrieved, 27 studies were included in the systematic review and 24 studies were included in the meta-analysis. Studies inducing increases in performance showed small increases in resting RMSSD [standardised mean difference (SMD) = 0.58 P < 0.001], HFP (SMD = 0.55 P < 0.001) and SD1 (SMD = 0.23 P = 0.16), and moderate increases in post-exercise RMSSD (SMD = 0.60 P < 0.001), HFP (SMD = 0.90 P < 0.04), SD1 (SMD = 1.20 P = 0.04), and post-exercise HRR (SMD = 0.63 P = 0.002). A large increase in HR acceleration (SMD = 1.34) was found in the single study assessing this parameter. Studies inducing decreases in performance showed a small increase in resting RMSSD (SMD = 0.26 P = 0.01), but trivial changes in resting HFP (SMD = 0.04 P = 0.77) and SD1 (SMD = 0.04 P = 0.82). Post-exercise RMSSD (SMD = 0.64 P = 0.04) and HFP (SMD = 0.49 P = 0.18) were increased, as was HRR (SMD = 0.46 P < 0.001), while HR acceleration was decreased (SMD = -0.48 P < 0.001). Increases in vagal-related indices of resting and post-exercise HRV, post-exercise HRR, and HR acceleration are evident when positive adaptation to training has occurred, allowing for increases in performance. However, increases in post-exercise HRV and HRR also occur in response to overreaching, demonstrating that additional measures of training tolerance may be required to determine whether training-induced changes in these parameters are related to positive or negative adaptations. Resting HRV is largely unaffected by overreaching, although this may be the result of methodological issues that warrant further investigation. HR acceleration appears to decrease in response to overreaching training, and thus may be a potential indicator of training-induced fatigue.
Publisher: Hindawi Limited
Date: 02-2021
DOI: 10.1111/PEDI.13178
Abstract: We aimed to characterize associations between diet and the gut microbiome and short chain fatty acid (SCFA) products in youth with islet autoimmunity or type 1 diabetes (IA/T1D) in comparison with controls. Eighty participants (25 diagnosed with T1D, 17 with confirmed IA, 38 sibling or unrelated controls) from the Australian T1D Gut Study cohort were studied (median [IQR] age 11.7 [8.9, 14.0] years, 43% female). A Food Frequency Questionnaire characterized daily macronutrient intake over the preceding 6 months. Plasma and fecal SCFA were measured by gas chromatography gut microbiome composition and ersity by 16S rRNA gene sequencing. A 10 g increase in daily carbohydrate intake associated with higher plasma acetate in IA/T1D (adjusted estimate +5.2 (95% CI 1.1, 9.2) μmol/L p = 0.01) and controls (adjusted estimate +4.1 [95% CI 1.7, 8.5] μmol/L p = 0.04). A 5 g increase in total fat intake associated with lower plasma acetate in IA/T1D and controls. A 5% increase in noncore (junk) food intake associated with reduced richness (adjusted estimate -4.09 [95%CI -7.83, -0.35] p = .03) and evenness (-1.25 [95% CI -2.00, -0.49] p < 0.01) of the gut microbiome in IA/T1D. Fiber intake associated with community structure of the microbiome in IA/T1D. Modest increments in carbohydrate and fat intake associated with plasma acetate in all youth. Increased junk food intake associated with reduced ersity of the gut microbiome in IA/T1D alone. These associations with the gut microbiome in IA/T1D support future efforts to promote SCFA by using dietary interventions.
Publisher: The Endocrine Society
Date: 09-2008
DOI: 10.1210/JC.2008-0751
Publisher: MDPI AG
Date: 26-02-2019
DOI: 10.3390/NU11030492
Abstract: Background/objectives: Polycystic ovary syndrome (PCOS) is a common condition in reproductive-aged women. Weight management is a first-line treatment for PCOS according to international evidence-based guidelines. However, the factors associated with attrition or success in weight loss interventions are not known for women with PCOS. The objective of this study was to identify characteristics associated with attrition and weight loss success in women with PCOS and overweight or obesity undergoing weight loss interventions. Methods: Four randomised controlled clinical weight loss trials comprising energy restricted diets and/or exercise interventions of 2–8 months duration. The interventions were conducted over 2001–2007 in outpatient clinical research centres with n = 221 premenopausal women with PCOS and overweight/obesity recruited through community advertisement. The main outcome measures were attrition and ≥5% weight loss at 2 months and study completion. Results: Weight loss was 5.7 ± 2.9 kg at 2 months and 7.4 ± 5.3 kg after study completion (p 0.001). Attrition was 47.1% and ≥5% weight loss occurred in 62.5% and 62.7% of women at 2 months and study completion respectively. Baseline depressive symptoms (OR 1.07 95% CI 0.88, 0.96, p = 0.032) and lower appointment attendance by 2 months (OR 0.92 95% CI 0.88, 0.96, p 0.001) were independently associated with attrition. Lower appointment attendance over the whole study was independently associated with not achieving ≥5% weight loss at study completion (OR 0.95 95% CI 0.92, 0.99, p = 0.020). Conclusions: Despite high attrition, successful weight loss was achieved by 63% of women with PCOS in a clinical research setting. Higher baseline depressive symptoms were associated with greater attrition and higher appointment attendance was associated with lower attrition and greater weight loss success. These finding have implications for development of successful weight management programs in PCOS.
Publisher: Wiley
Date: 14-08-2012
DOI: 10.1111/J.1365-2265.2012.04434.X
Abstract: Vitamin D deficiency is common in women with polycystic ovary syndrome (PCOS), with the 67-85% of women with PCOS having serum concentrations of 25-hydroxy vitamin D (25OHD) <20 ng/ml. Vitamin D deficiency may exacerbate symptoms of PCOS, with observational studies showing lower 25OHD levels were associated with insulin resistance, ovulatory and menstrual irregularities, lower pregnancy success, hirsutism, hyperandrogenism, obesity and elevated cardiovascular disease risk factors. There is some, but limited, evidence for beneficial effects of vitamin D supplementation on menstrual dysfunction and insulin resistance in women with PCOS. Vitamin D deficiency may play a role in exacerbating PCOS, and there may be a place for vitamin D supplementation in the management of this syndrome, but current evidence is limited and additional randomized controlled trials are required to confirm the potential benefits of vitamin D supplementation in this population.
Publisher: Elsevier BV
Date: 07-2016
DOI: 10.1016/J.JSAMS.2015.07.006
Abstract: Reductions in maximal rate of heart rate increase (rHRI) correlate with performance reductions when training load is increased. This study evaluated whether rHRI tracked performance changes across a range of training states. Prospective intervention. rHRI was assessed during five min of cycling at 100W (rHRIcyc) and running at 8km/h (rHRIrun) in 13 male triathletes following two weeks of light-training (LT), two weeks of heavy-training (HT) and a two-day recovery period (RP). A five min cycling time-trial assessed performance and peak oxygen consumption (V˙O2peak). Performance likely decreased following HT (Effect size±90% confidence interval=-0.18±0.09), then very likely increased following RP (0.32±0.14). rHRIcyc very likely decreased (-0.48±0.24), and rHRIrun possibly decreased (-0.33±0.48), following HT. Changes in both measures were unclear following RP. Steady-state HR was almost certainly lower (-0.81±0.31) during rHRIcyc than rHRIrun. A large correlation was found between reductions in performance and rHRIrun (r±90% CI=0.65±0.34) from LT to HT, but was unclear for rHRIcyc. Trivial within-subject correlations were found between rHRI and performance, but the strength of relationship between rHRIrun and performance was largely associated with V˙O2peak following LT (r=-0.58±0.38). Performance reductions were most sensitively tracked by rHRIrun following HT. This may be due to rHRIrun being assessed at a higher intensity than rHRIcyc, inferred from a higher steady-state HR and supported by a stronger within-subject relationship between rHRIrun and performance in in iduals with a lower V˙O2peak, in whom the same exercise intensity would represent a greater physiological stress. rHRI assessed at relatively high exercise intensities may better track performance changes.
Publisher: Wiley
Date: 07-01-2019
DOI: 10.1111/JPC.14373
Abstract: We aimed to evaluate the diets of children with type 1 diabetes (T1D) against recommended Australian dietary intakes and international T1D guidelines and compare them to children without T1D. A cross-sectional analysis in 143 children (103 children aged 8-18 years with T1D and 40 age- and gender-matched controls) and longitudinal analysis at 0, 3, 6 and 12 months in 90 T1D children were conducted. Diet was assessed using an Australian validated food frequency questionnaire. Diet quality was assessed against recommended servings and nutrient intakes from Australian Dietary Guidelines and International Society for Pediatric and Adolescent Diabetes (ISPAD) Nutritional Guidelines. Diet was evaluated in 478 questionnaires. Diet composition did not differ between T1D and controls, and both groups did not meet the majority of the Australian Dietary Guidelines, except for fruit intake. The majority of T1D children and controls (80-83%) were overconsuming sodium (2837 ± 848 mg/day), discretionary foods (5.9 ± 2.5 serves/day) and saturated fat and trans fatty acids (13.1 ± 2.7% of total daily energy intake) in comparison with Australian and ISPAD guidelines. A total of 84% of T1D children and controls achieved the recommended intake of fibre (34.4 ± 11.0 g/day). Longitudinal analysis in children with T1D showed that total daily energy, macronutrient, micronutrient and food group servings intake did not change over the 12 months. Overconsumption of sodium, discretionary foods and saturated fat persisted over the 12-month study period. The majority of Australian children, with and without T1D, is not meeting recommended dietary guidelines. Significant overconsumption of sodium, saturated fat and discretionary foods attracts the most concern.
Publisher: Hindawi Limited
Date: 09-06-2020
DOI: 10.1111/PEDI.13056
Publisher: Oxford University Press (OUP)
Date: 16-01-2019
DOI: 10.1093/OFID/OFZ025
Abstract: The importance of gut bacteria in human physiology, immune regulation, and disease pathogenesis is well established. In contrast, the composition and dynamics of the gut virome are largely unknown particularly lacking are studies in pregnancy. We used comprehensive virome capture sequencing to characterize the gut virome of pregnant women with and without type 1 diabetes (T1D), longitudinally followed in the Environmental Determinants of Islet Autoimmunity study. In total, 61 pregnant women (35 with T1D and 26 without) from Australia were examined. Nucleic acid was extracted from serial fecal specimens obtained at prenatal visits, and viral genomes were sequenced by virome capture enrichment. The frequency, richness, and abundance of viruses were compared between women with and without T1D. Two viruses were more prevalent in pregnant women with T1D: picobirnaviruses (odds ratio [OR], 4.2 95% confidence interval [CI], 1.0–17.1 P = .046) and tobamoviruses (OR, 3.2 95% CI, 1.1–9.3 P = .037). The abundance of 77 viruses significantly differed between the 2 maternal groups (≥2-fold difference P & .02), including 8 Enterovirus B types present at a higher abundance in women with T1D. These findings provide novel insight into the composition of the gut virome during pregnancy and demonstrate a distinct profile of viruses in women with T1D.
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.FERTNSTERT.2008.12.003
Abstract: To determine the effects of weight loss on heart rate recovery (HRR) in overweight women with polycystic ovary syndrome (PCOS). A 10-week prospective clinical intervention. Clinical research unit. Fifty-seven overweight and obese women with PCOS (age: 29.8 +/- 0.8 years body mass index [BMI] 36.2 +/- 0.7 kg/m(2)). A dietary plan of 5-6 MJ/day ( approximately 30% energy restricted). Heart rate recovery (defined as the reduction in heart rate after 1 minute from peak heart rate after a graded treadmill test to exhaustion), weight, waist circumference, blood pressure, glucose, insulin, homeostasis model assessment of insulin resistance, and sex steroids before and after the intervention. The mean percentage of weight loss was (-6.7 +/- 0.4%). There were significant reductions in waist circumference (-6.9 +/- 0.6 cm), blood pressure (-4.9/-2.5 +/- 1.2/1.2 mm Hg), fasting insulin (-3.4 +/- 0.7 mU/L), fasting glucose (-0.17 +/- 0.05 mmol/L), homeostasis model assessment of insulin resistance (-0.43 +/- 0.09), T (-0.38 +/- 0.07 nmol/L), free androgen index (-2.86 +/- 0.58), and an increase in sex hormone-binding globulin [SHBG] (5.86 +/- 1.12 nmol/L). The HRR improved from 30.9 +/- 1.1 to 38.0 +/- 1.1 beats/min and that was related to the reduction in body weight (r = -0.34) and waist circumference (r = -0.27). Weight loss in overweight and obese women with PCOS is associated with improvements in HRR, which suggests improved autonomic function. This highlights the importance of weight loss to reduce the cardiovascular disease risk in these women.
Publisher: Springer Science and Business Media LLC
Date: 03-09-2020
DOI: 10.1038/S41598-020-71597-4
Abstract: Maximal rate of heart rate (HR) increase (rHRI) as a measure of HR acceleration during the transition from rest to exercise, or during an increase in workload, tracks exercise performance. rHRI assessed at relative rather than absolute workloads may track performance better, and a field test would increase applicability. This study therefore aimed to evaluate the sensitivity of rHRI assessed at in idualised relative workloads during treadmill and overground running for tracking exercise performance. Treadmill running performance (5 km time trial 5TTT) and rHRI were assessed in 11 male runners following 1 week of light training (LT), 2 weeks of heavy training (HT) and a 10-day taper (T). rHRI was the first derivative maximum of a sigmoidal curve fit to HR data collected during 5 min of treadmill running at 65% peak HR (rHRI65%), and subsequent transition to 85% peak HR (rHRI85%). Participants ran at the same speeds overground, paced by a foot-mounted accelerometer. Time to complete 5TTT likely increased following HT (ES = 0.14 ± 0.03), and almost certainly decreased following T (ES = − 0.30 ± 0.07). Treadmill and field rHRI65% likely increased after HT in comparison to LT (ES ≤ 0.48 ± 0.32), and was unchanged at T. Treadmill and field rHRI85% was unchanged at HT in comparison to LT, and likely decreased at T in comparison to LT (ES ≤ − 0.55 ± 0.50). 5TTT was not correlated with treadmill or field rHRI65% or rHRI85%. rHRI65% was highly correlated between treadmill and field tests across LT, HT and T (r ≥ 0.63), but correlations for rHRI85% were trivial to moderate (r ≤ 0.42). rHRI assessed at relative exercise intensities does not track performance. rHRI assessed during the transition from rest to running overground and on a treadmill at the same running speed were highly correlated, suggesting that rHRI can be validly assessed under field conditions at 65% of peak HR.
Publisher: Hindawi Limited
Date: 20-05-2019
DOI: 10.1111/PEDI.12865
Abstract: To investigate the longitudinal relationship between the gut microbiome, circulating short chain fatty acids (SCFAs) and intestinal permeability in children with islet autoimmunity or type 1 diabetes and controls. We analyzed the gut bacterial microbiome, plasma SCFAs, small intestinal permeability and dietary intake in 47 children with islet autoimmunity or recent-onset type 1 diabetes and in 41 unrelated or sibling controls over a median (range) of 13 (2-34) months follow-up. Children with multiple islet autoantibodies (≥2 IA) or type 1 diabetes had gut microbiome dysbiosis. Anti-inflammatory Prevotella and Butyricimonas genera were less abundant and these changes were not explained by differences in diet. Small intestinal permeability measured by blood lactulose:rhamnose ratio was higher in type 1 diabetes. Children with ≥2 IA who progressed to type 1 diabetes (progressors), compared to those who did not progress, had higher intestinal permeability (mean [SE] difference +5.14 [2.0], 95% confidence interval [CI] 1.21, 9.07, P = .006), lower within-s le (alpha) microbial ersity (31.3 [11.2], 95% CI 9.3, 53.3, P = .005), and lower abundance of SCFA-producing bacteria. Alpha ersity (observed richness) correlated with plasma acetate levels in all groups combined (regression coefficient [SE] 0.57 [0.21], 95% CI 0.15, 0.99 P = .008). Children with ≥2 IA who progress to diabetes, like those with recent-onset diabetes, have gut microbiome dysbiosis associated with increased intestinal permeability. Interventions that expand gut microbial ersity, in particular SCFA-producing bacteria, may have a role to decrease progression to diabetes in children at-risk.
Publisher: Hindawi Limited
Date: 15-08-2016
DOI: 10.1111/PEDI.12425
Abstract: The incidence of type 1 diabetes globally has increased dramatically over the last 50 years. Proposed environmental reasons for this increase mirror the modern lifestyle. Type 1 diabetes can be viewed as part of the non- communicable disease epidemic in our modern society. Meanwhile rapidly evolving new technologies are advancing our understanding of how human microbial communities interface with the immune system and metabolism, and how the modern pro-inflammatory environment is changing these communities and contributing to the rapid rise of non-communicable disease. The majority of children who present with clinical type 1 diabetes are of school age however 80% of children who develop type 1 diabetes by 18 years of age will have detectable islet autoantibodies by 3 years of age. The evolving concept that type 1 diabetes in many children has developmental origins has directed research questions in search of prevention back to pregnancy and early life. To this end the world's first pregnancy to early childhood cohort study in at-risk children has commenced.
Publisher: Informa UK Limited
Date: 12-04-2023
Publisher: CRC Press
Date: 24-02-2015
DOI: 10.1201/B18190-6
Publisher: Oxford University Press (OUP)
Date: 02-05-2012
Abstract: Women with polycystic ovary syndrome (PCOS) present with vascular abnormalities, including elevated markers of endothelial dysfunction. There is limited evidence for the effect of lifestyle modification and weight loss on these markers. The aim of this study was to determine if 20 weeks of a high-protein energy-restricted diet with or without exercise in women with PCOS could improve endothelial function. This is a secondary analysis of a subset of 50 overweight/obese women with PCOS (age: 30.3 ± 6.3 years BMI: 36.5 ± 5.7 kg/m(2)) from a previous study. Participants were randomly assigned by computer generation to one of three 20-week interventions: diet only (DO n = 14, ≈ 6000 kJ/day), diet and aerobic exercise (DA n = 16, ≈ 6000 kJ/day and five walking sessions/week) and diet and combined aerobic-resistance exercise (DC n = 20, ≈ 6000 kJ/day, three walking and two strength sessions/week). At Weeks 0 and 20, weight, markers of endothelial function [vascular cell adhesion molecule-1 (sVCAM-1), inter-cellular adhesion molecule-1 (sICAM-1), plasminogen activator inhibitor-1 (PAI-1) and asymmetric dimethylarginine (ADMA)], insulin resistance and hormonal profile were assessed. All three treatments resulted in significant weight loss (DO 7.9 ± 1.2%, DA 11.0 ± 1.6%, DC 8.8 ± 1.1 P < 0.001 for time P = 0.6 time × treatment). sVCAM-1, sICAM-1 and PAI-1 levels decreased with weight loss (P≤ 0.01), with no differences between treatments (P ≥ 0.4). ADMA levels did not change significantly (P = 0.06). Testosterone, sex hormone-binding globulin and the free androgen index (FAI) and insulin resistance also improved (P < 0.001) with no differences between treatments (P ≥ 0.2). Reductions in sVCAM-1 were correlated to reductions in testosterone (r = 0.32, P = 0.03) and FAI (r = 0.33, P = 0.02) as well as weight loss (r= 0.44, P = 0.002). Weight loss was also associated with reductions in sICAM-1 (r= 0.37, P = 0.008). Exercise training provided no additional benefit to following a high-protein, hypocaloric diet on markers of endothelial function in overweight/obese women with PCOS.
Publisher: Frontiers Media SA
Date: 14-12-2021
DOI: 10.3389/FPHYS.2021.771899
Abstract: Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) have been shown to exhibit altered ventilatory characteristics on the second of two progressive maximal cardiopulmonary exercise tests (CPET) performed on consecutive days. However, maximal exercise can exacerbate symptoms for ME/CFS patients and cause significant post-exertional malaise. Assessment of heart rate (HR) parameters known to track post-exertional fatigue may represent more effective physiological markers of the condition and could potentially negate the need for maximal exercise testing. Sixteen ME/CFS patients and 10 healthy controls underwent a sub-maximal warm-up followed by CPET on two consecutive days. Ventilation, ratings of perceived exertion, work rate (WR) and HR parameters were assessed throughout on both days. During sub-maximal warm-up, a time effect was identified for the ratio of low frequency to high frequency power of HR variability ( p =0.02) during sub-maximal warm-up, and for HR at ventilatory threshold ( p =0.03), with both being higher on Day Two of testing. A significant group ( p & .01) effect was identified for a lower post-exercise HR recovery (HRR) in ME/CFS patients. Receiver operator characteristic curve analysis of HRR revealed an area under the curve of 74.8% ( p =0.02) on Day One of testing, with a HRR of 34.5bpm maximising sensitivity (63%) and specificity (40%) suggesting while HRR values are altered in ME/CFS patients, low sensitivity and specificity limit its potential usefulness as a biomarker of the condition.
Publisher: Oxford University Press (OUP)
Date: 20-04-2009
Publisher: CRC Press
Date: 24-02-2015
DOI: 10.1201/B18190
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.CLNU.2015.01.018
Abstract: Maintenance of muscle mass and strength into older age is critical to maintain health. The aim was to determine whether increased dairy or soy protein intake combined with resistance training enhanced strength gains in older adults. 179 healthy older adults (age 61.5 ± 7.4 yrs, BMI 27.6 ± 3.6 kg/m(2)) performed resistance training three times per week for 12 weeks and were randomized to one of three eucaloric dietary treatments which delivered >20 g of protein at each main meal or immediately after resistance training: high dairy protein (HP-D, >1.2 g of protein/kg body weight/d ∼27 g/d dairy protein) high soy protein (HP-S, >1.2 g of protein/kg body weight/d ∼27 g/d soy protein) usual protein intake (UP, <1.2 g of protein/kg body weight/d). Muscle strength, body composition, physical function and quality of life were assessed at baseline and 12 weeks. Treatments effects were analyzed using two-way ANOVA. 83 participants completed the intervention per protocol (HP-D = 34, HP-S = 26, UP = 23). Protein intake was higher in HP-D and HP-S compared with UP (HP-D 1.41 ± 0.14 g/kg/d, HP-S 1.42 ± 0.61 g/kg/d, UP 1.10 ± 0.10 g/kg/d P 0.06). Increased soy protein intake attenuated gains in muscle strength during resistance training in older adults compared with increased intake of dairy protein or usual protein intake. ACTRN12612000177853 www.anzctr.org.au.
Publisher: Springer Science and Business Media LLC
Date: 14-03-2019
Publisher: Elsevier BV
Date: 10-2010
Publisher: Informa UK Limited
Date: 13-06-2018
DOI: 10.1080/02701367.2018.1475722
Abstract: Correlations between fatigue-induced changes in exercise performance and maximal rate of heart rate (HR) increase (rHRI) may be affected by exercise intensity during assessment. This study evaluated the sensitivity of rHRI for tracking performance when assessed at varying exercise intensities. Performance (time to complete a 5-km treadmill time-trial [5TTT]) and rHRI were assessed in 15 male runners following 1 week of light training, 2 weeks of heavy training (HT), and a 10-day taper (T). Maximal rate of HR increase (measured in bpm·s Time to complete a 5-km treadmill time-trial was likely slower following HT (effect size ± 90% confidence interval = 0.16 ± 0.06), and almost certainly faster following T (-0.34 ± 0.08). Maximal rate of HR increase during 5 min of running at 8 km·h The 5TTT performance was tracked by both rHRI
Publisher: Elsevier BV
Date: 12-2016
Publisher: Springer Science and Business Media LLC
Date: 09-10-2017
DOI: 10.1007/S00421-017-3728-4
Abstract: Being able to identify how an athlete is responding to training would be useful to optimise adaptation and performance. The maximal rate of heart rate increase (rHRI), a marker of heart rate acceleration has been shown to correlate with performance changes in response to changes in training load in male athletes however, it has not been established if it also correlates with performance changes in female athletes. rHRI and cycling performance were assessed in six female cyclists following 7 days of light training (LT), 14 days of heavy training (HT) and a 10 day taper period. rHRI was the first derivative maximum of a sigmoidal curve fit to R-R data recorded during 5 min of cycling at 100 W. Cycling performance was assessed as work done (kJ) during time-trials of 5 (5TT) and 60 (60TT) min duration. 5TT was possibly decreased at HT (ES ± 90% confidence interval = - 0.16 ± 0.25 p = 0.60), while, 5TT and 60TT very likely to almost certainly increased from HT to taper (ES = 0.71 ± 0.24 p = 0.007 and ES = 0.42 ± 0.19 p = 0.02, respectively). Large within-subject correlations were found between rHRI, and 5TT (r = 0.65 ± 0.37 p = 0.02) and 60TT (r = 0.70 ± 0.31 p = 0.008). rHRI during the transition from rest to light exercise correlates with training induced-changes in exercise performance in females, suggesting that rHRI may be a useful monitoring tool for female athletes.
Publisher: Springer Science and Business Media LLC
Date: 13-02-2020
DOI: 10.1038/S41598-020-59369-6
Abstract: The maximal rate of heart rate (HR) increase (rHRI), a marker of HR acceleration during transition from rest to submaximal exercise, correlates with exercise performance. In this cohort study, whether rHRI tracked performance better when evaluated over shorter time-periods which include a greater proportion of HR acceleration and less steady-state HR was evaluated. rHRI and five-km treadmill running time-trial performance (5TTT) were assessed in 15 runners following one week of light training (LT), two weeks of heavy training (HT) and 10-day taper (T). rHRI was the first derivative maximum of a sigmoidal curve fit to one, two, three and four minutes of R-R data during transition from rest to running at 8 km/h (rHRI 8 km/h ), 10.5 km/h , 13 km/h and transition from 8 to 13 km/h (rHRI 8–13km/h ). 5TTT time increased from LT to HT (effect size [ES] 1.0, p 0.001) then decreased from HT to T (ES −1.7, p 0.001). 5TTT time was inversely related to rHRI 8 km/h assessed over two (B = −5.54 , p = 0.04) three (B = −5.34 , p = 0.04) and four (B = −5.37 , p = 0.04) minutes, and rHRI 8–13km/h over one (B = −11.62 , p = 0.006) and three (B = −11.44 , p = 0.03) minutes. 5TTT correlated most consistently with rHRI 8 km/h . rHRI 8 km/h assessed over two to four minutes may be suitable for evaluating athlete responses to training.
Publisher: JMIR Publications Inc.
Date: 04-10-2021
Abstract: ecruitment and retention of research participants is challenging. Social media, particularly Facebook, has emerged as a tool for connecting with participants due to its high uptake in the community. The Environmental Determinants of Islet Autoimmunity (ENDIA) study is an Australia-wide prospective pregnancy-birth cohort following children who have a first-degree relative with type 1 diabetes (ACTRN1261300794707). A dedicated Facebook page was established for the ENDIA study in 2013 with the aim to enhance recruitment and support participant retention. he purpose of this investigation was to evaluate the long-term impact of Facebook as a recruitment and retention tool. The hypotheses were that (1) Facebook was an important source of referral to the ENDIA study, (2) the sociodemographic characteristics of participants recruited by Facebook would be different from those of participants recruited by other means (i.e., ‘conventional recruits’), and (3) recruitment by Facebook would be associated with long-term retention. We also evaluated the most effective types of Facebook content based on post engagement. ecruitment of 1511 ENDIA participants was completed in December 2019. Characteristics of participants recruited through Facebook were compared to conventional recruits using linear, logistic, and multinomial logistic regression models. A logistic regression model was used to determine the risk of study withdrawal. Data pertaining to 794 Facebook posts over 7.5 years from June 2013 until December 2020 were extracted using the Facebook ‘Insights’ function for thematic analysis. acebook was the third largest source of referral to the ENDIA study (300/1511 19.9%) behind in-person clinics (500/1511, 33.1%) and healthcare professional referrals (347/1511, 23.0%). The ENDIA Facebook page had 2337 followers at the close of recruitment. Approximately 20% of these could be identified as participating parents. Facebook recruits were more frequently Australian-born (P .001) enrolling postnatally (P=.01) and withdrew from the study at a significantly lower rate compared to conventional recruits (4.7% vs 12.3% P .001) after a median of follow-up of 3.3 years. acebook was a valuable recruitment tool for the ENDIA study and participants recruited through Facebook were three times less likely to withdraw during long-term follow-up. The sociodemographic characteristics of Facebook recruits were different to conventional recruits, but perhaps in unintended ways. Facebook content featuring stories and images of participants received the highest engagement despite the fact that most Facebook followers were not enrolled in the study. These findings should inform social media strategies for future cohort studies involving pregnant women and young families, and for type 1 diabetes risk studies. ustralia New Zealand Clinical Trials Registry: ACTRN1261300794707 R2-0.1186/1471-2431-13-124
Publisher: Springer Science and Business Media LLC
Date: 10-05-2015
DOI: 10.1007/S12020-015-0625-7
Abstract: Polycystic ovary syndrome (PCOS) is a common condition affecting reproductive-aged women with features including hyperandrogenism and menstrual irregularity frequently treated with hormonal steroidal contraceptives. Women with PCOS appear to have lower bone mineral density (BMD). While steroidal contraceptives may positively affect bone health, their effect on BMD in PCOS is not known. The aim of this study was to assess BMD in women with PCOS according to recent contraceptive use. A cross-sectional analysis of 95 pre-menopausal overweight or obese sedentary women with PCOS [age 29.4 ± 6.4 years, body mass index (BMI) 36.1 ± 5.3 kg/m(2)] who either recently took steroidal contraceptives (ceased 3 months prior) or were not taking steroidal contraceptives was conducted. Clinical outcomes included BMD, anthropometry, insulin, glucose, reproductive hormones, dietary intake and vitamin use. BMD was significantly lower for women who used contraceptives compared to those who did not (mean difference 0.06 g/cm(2) 95 % confidence interval -0.11, -0.02, p = 0.005). In regression models, lower BMD was independently associated with contraceptive use (β = -0.05, 95 % CI -0.094, -0.002, p = 0.042), higher testosterone (β = -0.03, 95 % CI -0.05, -0.0008, p = 0.043) and lower BMI (β = 0.006, 95 % CI 0.002, 0.01, p = 0.007) (r (2) = 0.22, p = 0.001 for entire model). We report for the first time that overweight and obese women with PCOS with recent steroidal contraceptive use had lower BMD in comparison to non-users independent of factors known to contribute to BMD. Whether this observation is directly related to steroidal contraceptive use or other factors requires further investigation.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2013
Publisher: Elsevier BV
Date: 03-2016
DOI: 10.1016/J.JSAMS.2015.02.010
Abstract: The recovery of heart rate (HRR) after exercise is a potential indicator of fitness which has been shown to respond to changes in training. This study investigated the within-in idual association between HRR and exercise performance following three different training loads. 11 male cyclists/triathletes were tested after two weeks of light training, two weeks of heavy training and two days of rest. Exercise performance was measured using a 5-min maximal cycling time-trial. HRR was measured over 60s during supine recovery. Exercise performance decreased 2.2±2.5% following heavy training compared with post-light training (p=0.01), and then increased 4.0±4.2% following rest (p=0.004). Most HRR indices indicated a more rapid recovery of heart rate (HR) following heavy training, and reverted to post light training levels following two days of rest. HRR indices did not differ between post-light training and after the rest period (p>0.6). There were inverse within-subject relationships between indices of HRR and performance (r=-0.6, p≤0.004). Peak HR decreased 3.2±5.1bpm following heavy training (p=0.06) and significantly increased 4.9±4.3bpm following recovery (p=0.004). There was a moderate within-subject relationship between peak HR and exercise performance (r=0.7, p≤0.001). Controlling for peak HR reduced the relationships between HRR and performance (r=-0.4-0.5, p<0.05). This study demonstrated that HRR tracks short-term changes in exercise performance within-in iduals, such that increases in HRR are associated with poorer exercise performance following heavy training. Peak HR can be compromised under conditions of fatigue, and needs to be taken into account in HRR analyses.
Publisher: Wiley
Date: 17-06-2020
DOI: 10.1111/DME.13987
Abstract: To measure pancreatic area and exocrine function in young children with recent-onset Type 1 diabetes to determine whether the exocrine pancreas is also affected in the pathophysiology of early childhood diabetes. Thirty-two children (14 boys) aged 5.5 (4.5, 7.3) median (IQR) years presenting with recent-onset Type 1 diabetes and 90 controls (44 boys) of similar age had ultrasound imaging of the pancreas. Children with Type 1 diabetes were receiving insulin and were without ketosis. Transverse and longitudinal areas of the pancreas were measured by digitalized outline. Pancreatic faecal elastase-1 was analysed using an enzyme-linked immunosorbent assay kit in recent-onset Type 1 diabetes and 38 first-degree relative control children. Pancreatic area and exocrine function were reduced in Type 1 diabetes. Mean transverse area (SD) in Type 1 diabetes was 6.82 cm Pancreatic area and accompanying subclinical exocrine function were reduced in very young children with recent-onset Type 1 diabetes. This supports changes in the exocrine pancreas in the pathophysiology of Type 1 diabetes presenting in early life.
Publisher: Wiley
Date: 02-08-2012
Publisher: MDPI AG
Date: 05-07-2012
DOI: 10.3390/NU4070711
Publisher: MDPI AG
Date: 09-02-2021
Abstract: The effect of the menstrual cycle on physical performance is being increasingly recognised as a key consideration for women’s sport and a critical field for further research. This narrative review explores the findings of studies investigating the effects of menstrual cycle phase on perceived and objectively measured performance in an athletic population. Studies examining perceived performance consistently report that female athletes identify their performance to be relatively worse during the early follicular and late luteal phases. Studies examining objective performance (using anaerobic, aerobic or strength-related tests) do not report clear, consistent effects of the impact of menstrual cycle phase on physical performance. Overall sport performance can be influenced by both perceived and physical factors. Hence, to optimise performance and management of eumenorrheic female athletes, there is a need for further research to quantify the impact of menstrual cycle phase on perceived and physical performance outcomes and to identify factors affecting variability in objective performance outcomes between studies.
Publisher: Springer Science and Business Media LLC
Date: 11-02-2017
DOI: 10.1007/S00421-017-3549-5
Abstract: Correlations between fatigue-induced changes in performance and maximal rate of HR increase (rHRI) may be affected by differing assessment workloads. This study evaluated the effect of assessing rHRI at different workloads on performance tracking, and compared this with HR variability (HRV) and HR recovery (HRR). Performance [5-min cycling time trial (5TT)], rHRI (at multiple workloads), HRV and HRR were assessed in 12 male cyclists following 1 week of light training (LT), 2 weeks of heavy training (HT) and a 10-day taper (T). 5TT very likely decreased after HT (effect size ± 90% confidence interval = -0.75 ± 0.41), and almost certainly increased after T (1.15 ± 0.48). rHRI at 200 W likely increased at HT (0.70 ± 0.60), and then likely decreased at T (-0.50 ± 0.70). rHRI at 120 and 160 W was unchanged. Pre-exercise HR during rHRI assessments at 120 W and 160 W likely decreased after HT (≤-0.39 ± 0.14), and correlations between these changes and rHRI were large to very large (r = -0.67 ± 0.31 and r = -0.78 ± 0.23). When controlling for pre-exercise HR, rHRI at 120 W very likely slowed after HT (-0.72 ± 0.44), and was moderately correlated with 5TT (r = 0.35 ± 0.32). RMSSD likely increased at HT (0.75 ± 0.49) and likely decreased at T (-0.49 ± 0.49). HRR following 5TT likely increased at HT (0.84 ± 0.31) and then likely decreased at T (-0.81 ± 0.35). When controlling for pre-exercise HR, rHRI assessment at 120 W most sensitively tracked performance. Increased RMSSD following HT indicated heightened parasympathetic modulation in fatigued athletes. HRR was only sensitive to changes in training status when assessed after maximal exercise, which may limit its practical applicability.
Publisher: Informa UK Limited
Date: 20-08-2015
DOI: 10.1080/15438627.2015.1076414
Abstract: Different mathematical models were used to evaluate if the maximal rate of heart rate (HR) increase (rHRI) was related to reductions in exercise performance resulting from acute fatigue. Fourteen triathletes completed testing before and after a 2-h run. rHRI was assessed during 5 min of 100-W cycling and a sigmoidal (rHRIsig) and exponential (rHRIexp) model were applied. Exercise performance was assessed using a 5-min cycling time-trial. The run elicited reductions in time-trial performance (1.34 ± 0.19 to 1.25 ± 0.18 kJ · kg(-1), P < 0.001), rHRIsig (2.25 ± 1.0 to 1.14 ± 0.7 beats · min(-1) · s(-1), P < 0.001) and rHRIexp (3.79 ± 2.07 to 1.98 ± 1.05 beats · min(-1) · s(-1), P = 0.001), and increased pre-exercise HR (73.0 ± 8.4 to 90.5 ± 11.4 beats · min(-1), P < 0.001). Pre-post run difference in time-trial performance was related to difference in rHRIsig (r = 0.58, P = 0.04 and r = 0.75, P = 0.003) but not rHRIexp (r = -0.04, P = 0.9 and r = 0.27, P = 0.4) when controlling for differences in pre-exercise and steady-state HR. rHRIsig was reduced following acute exercise-induced fatigue, and correlated with difference in performance.
No related grants have been discovered for Rebecca Thomson.