ORCID Profile
0000-0002-5300-369X
Current Organisations
University of North Carolina at Chapel Hill
,
University of Maryland
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Publisher: American Physiological Society
Date: 09-2019
DOI: 10.1152/JAPPLPHYSIOL.00318.2019
Abstract: Prolonged sitting has been shown to promote endothelial dysfunction in the lower legs. Furthermore, it has been reported that simple sitting-interruption strategies, including calf raises, prevent leg endothelial dysfunction. However, it is unclear whether prolonged sitting affects central cardiovascular health, or whether simple sitting-interruption strategies prevent impaired central cardiovascular health. This study sought to answer two questions: in young, healthy adults
Publisher: Wiley
Date: 12-07-2020
DOI: 10.1113/EP088690
Abstract: What is the central question of this study? What are the cellular and molecular determinants of increased risk for cardiovascular disease from prolonged sitting? What is the main finding and its importance? Prolonged sitting, independent of calf raise interruption strategies, decreases microparticle counts linked to endothelial activation and apoptosis. An acute bout of prolonged sitting appears to promote paradoxical decreases in microparticle counts, but the implications are not yet clear. Repeated exposure to prolonged sitting increases the risk for cardiovascular disease. However, the cellular links by which repeated exposure to prolonged sitting lead to increased cardiovascular risk have not been fully elucidated, with markers of vascular damage and repair such as microparticles (MPs) and circulating angiogenic cell (CACs) being promising targets. The objective of the study was to examine the effects of 3 h of sitting with or without intermittent calf raises on annexin V + /CD34 + , annexin V + /CD62E + , and annexin V + /CD31 + /42b − MP populations linked to CAC paracrine activity, endothelial activation and apoptosis, respectively, as well as CD14 + /31 + , CD3 + /31 + , and CD34 + CACs, which are linked to endothelial repair. In a random order, 20 sedentary participants (14 females, 22 ± 3 years) remained seated for 180 min with or without performing 10 calf raises every 10 min. Blood s les were obtained after 20 min of quiet rest in the supine position before and after sitting. Overall, sitting decreased annexin V + /CD34 + MPs (−12 ± 5 events µl −1 , P 0.01), annexin V + /CD62E + MPs (−17 ± 4 events µl −1 , P 0.001), and annexin V + /CD31 + /42b − MPs (−22 ± 6 events µl −1 , P 0.001) regardless of condition. There were no differences in endothelin‐1 plasma concentration, CD14 + /31 + , CD34 + or CD3 + /31 + CAC frequencies. Sitting did not alter CAC number, but decreased MPs linked to endothelial activation, apoptosis and CAC paracrine activity in a manner that was independent of muscle contraction. These findings support changes in markers of endothelial activation and apoptosis with sedentary behaviour and provide new insights into altered intercellular communication with physical inactivity such as prolonged sitting.
Publisher: Wiley
Date: 08-05-2018
DOI: 10.1111/SMS.13199
Abstract: Exercise training reduces the side effects of cancer treatments however, the stress hormone response to acute exercise during prostate cancer (PCa) treatment is unclear. The study purpose was to examine the effects of acute exercise on circulating cortisol, epinephrine (Epi), and norepinephrine (NE) concentrations during PCa treatment with and without androgen deprivation therapy (ADT). Men with PCa (n = 11), with PCa on ADT (n = 11), and with non-cancer controls (n = 8) had blood s les for stress hormones collected before and immediately (0 hour), 2 hours, and 24 hours after 45 minutes of intermittent cycling at 60% of peak wattage. NE increased by 385% (P < .001) at 0 hour and remained elevated at 2 hours (P < .05) with no group differences. Overall, cortisol significantly increased at 0 hour (36%, P < .012) and then significantly decreased below baseline at 2 hours (-24%, P < .001) before returning to resting levels at 24 hours. Cortisol levels during ADT were 32% lower than PCa (P = .006) with no differences vs controls. Epi increased immediately after exercise more in controls (817%, P < .001) than with ADT (700%) and PCa (333%) patients, and both cancer groups' absolute levels were attenuated relative to controls (ADT: -54%, PCa: -52%, P = .004). Compared with age-matched controls, PCa and ADT patients exhibited similar stress hormone responses with acute exercise for NE and cortisol but an attenuated EPI response that suggests altered adrenal function. Future studies should examine the physical stress of multiple exercise bouts to verify these findings and to explore the functional hormonal effects, such as immune and metabolic responses, during cancer treatment.
Publisher: Wiley
Date: 17-08-2019
DOI: 10.1111/PSYP.13457
Abstract: Exposure to acute prolonged sitting reportedly leads to decreased cerebral blood flow. However, it is unclear whether this exposure translates to decreased cerebral perfusion and executive function or whether simple strategies to break up sitting can maintain cerebral perfusion and executive function. This study sought to answer two questions: in young, healthy adults, (a) does prolonged (3 hr) sitting lead to decreased cerebral perfusion and executive function? and (b) does breaking up prolonged sitting, using intermittent calf raise exercises, prevent changes in cerebral perfusion and executive function? Twenty young, healthy participants (21.7 [2.5] years, 70% female, 25.5 [6.1] kg/m
Publisher: Springer Science and Business Media LLC
Date: 24-10-2018
DOI: 10.1007/S40279-018-1001-6
Abstract: Arterial stiffness (AS) is a key measure in predicting risk for cardiovascular disease (CVD) and related events, independent of other risk factors. Resistance training (RT) has been shown to increase AS in young healthy subjects. However, the effects of RT on AS in persons with or at risk for CVD remain unclear this uncertainty is a barrier to RT prescription in this population. Considering RT may be as effective as or superior to aerobic exercise prescription in treating some co-morbidities associated with CVD, it would be helpful to clarify whether RT does lead to clinically meaningful increases (detrimental) in AS in those with CVD or CVD risk factors. The aim of this study was to (1) assess the effects of RT on measures of AS in at-risk populations, and (2) discuss the implications of the findings for clinical exercise physiologists. The electronic databases PubMed, Web of Science, SPORTDiscus, and Google Scholar were searched from inception to February 2018. The reference lists of eligible articles and reviews were also checked. Inclusion criteria were: (1) the trial was a randomized controlled trial (2) exercise prescription of RT or a combination of resistance and aerobic exercise for at least 8 weeks (3) control group characteristics allowed for comparison of the main effects of the exercise prescription (4) subjects had known CVD or a risk factor associated with CVD according to the American College of Sports Medicine (ACSM) guidelines (5) article measured at least carotid to femoral pulse wave velocity (PWV) or augmentation index (AIx). Initially, 1427 articles were identified. After evaluation of study characteristics, quality and validity data from 12 articles and 13 cohorts involving 651 participants (223 women, 338 men, 90 unknown) were extracted for the meta-analysis. To enable comparisons between assessments, and to infer clinical significance, standardized mean differences (SMD) were calculated. When data were not available, values were estimated according to Cochrane guidelines. According to the JADAD scale, the mean quality of studies was 3 out of 5. The duration of the included studies ranged from 8 weeks to 24 months. RT trended towards decreasing (improving) PWV (SMD = - 0.168, 95% CI - 0.854 to 0.152, p = 0.057). There were no significant differences in AIx (SMD = - 0.286), diastolic blood pressure (SMD = - 0.147), systolic blood pressure (SMD = - 0.126), or central systolic blood pressure (SMD = - 0.405). The available evidence suggests that RT does not increase (worsen) AS in patients who have or are at risk for CVD. Considering RT may be as effective as or superior to aerobic exercise prescription in treating some co-morbidities associated with CVD, these findings suggest that RT is a suitable exercise prescription in primary and secondary prevention settings.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 02-2019
DOI: 10.1249/MSS.0000000000001780
Abstract: Mucosal-associated invariant T (MAIT) cells have properties of both the innate and adaptive immune systems but are an understudied population within exercise immunology. These lymphocytes aggregate at the mucous membranes, but it is unknown if submaximal exercise alters their circulating numbers or function. To determine the MAIT cell response to submaximal exercise on activation and homing marker expression and stimulated cytokine production. Twenty healthy, young, recreationally active males cycled for 40 min at 86% of VT after an overnight fast. Peripheral blood mononuclear cells were isolated and labeled to identify specific MAIT cell populations using flow cytometry. Cytokine production after stimulation was also determined. Mucosal-associated invariant T cells were 2.9% of T cells and increased to 3.9% after exercise and with recovery whereas cell numbers significantly increased by 91.5% after exercise before returning to resting levels. Chemokine and activation marker absolute cell number significantly increased while expression levels remained constant but the high levels of CCR5 may help direct MAIT cells to sites of inflammation. After stimulation, TNFα expression significantly increased after exercise before returning to baseline with a similar trend for IFNγ. The MAIT cell numbers undergo a partial biphasic response after submaximal exercise and appear to be preferentially mobilized within T cells however, the magnitude of the submaximal response was attenuated relative to maximal exercise. Stimulated MAIT cells increase TNFα expression, indicating greater responsiveness to pathogens after acute exercise.
Location: United States of America
Location: United States of America
No related grants have been discovered for William Evans.