Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme最新文献

Sex and gender inequities in biomedical research are well-documented. To evaluate the recent exercise physiology literature, we analyzed participants, authors, and adherence to Sex and Gender Equity in Research (SAGER) guidelines in 629 systematically-selected original research articles (2018-2020) across six peer-reviewed journals. Nearly half of studies (46%) included only male/men (M/M) participants, 44% were mixed, and 8% were female/women (F/W)-only. Only 27% of authors were women, with even lower representation among senior authors (16%) and those with >2 publications (12%). Articles with women senior authors had 72% more women co-authors, and there was a dose-dependent association between women authors and inclusion of F/W participants. Articles adhered to 29 (20-43)% of relevant SAGER guidelines. Over half (58%) used inaccurate or unclear sex/gender-related language, and only 10-34% followed guidelines that support discovery of sex/gender-related differences. F/W-only articles were more likely than M/M-only to report (79% vs 12%), justify (69% vs 5%), and discuss (62% vs 20%) their single-sex/gender status. Articles with women authors were more likely to communicate clearly about sex/gender but otherwise had similarly poor adherence to SAGER guidelines. There are likely complex reasons why male bodies and men's voices continue to be centered in exercise physiology research. Our data implicate several logistical, attitudinal, and cultural contributors that warrant investigation and intervention. Structural support and enforcement will be needed to increase F/W inclusion and align research and reporting practices with SAGER guidelines. Associations between women authors and equitable practices suggest compound benefits of investing in recruitment and retention of women researchers.

Previous studies have shown that supraspinal excitability is higher during arm cycling than a position- and intensity-matched tonic contraction, but the underlying mechanisms remain unclear. This study aimed to determine whether long-interval intracortical inhibition (LICI) occurs during arm cycling and if LICI differs between arm cycling and tonic contraction. A paired-pulse transcranial magnetic stimulation (TMS) protocol assessed LICI using a supramaximal conditioning pulse that produced a silent period of approximately 150 ms, followed by a test pulse with a 100 ms interstimulus interval. Stimulation occurred at the 4 o'clock position to align the test pulse with the ascending limb of the biceps brachii EMG profile during the elbow flexion phase. Additionally, a single-pulse TMS stimulation was delivered 100 ms after the 4 o'clock position. Motor-evoked potentials (MEPs) were measured as ratios: a position-matched ratio of test pulse-evoked MEP over single pulse-evoked MEP. MEP ratios were analyzed for peak-to-peak amplitude during arm cycling and tonic contraction. Results showed that LICI was present during arm cycling (t(13) = 3.5, p < 0.001, 95% CI [-3.2, -0.75], but no significant difference in LICI was found between arm cycling and tonic contraction (t(13) = 1.3, p = 0.242, 95% CI [-0.23, -0.06]). These findings suggest that while LICI is present during arm cycling, it is not task-dependent.

To increase exercise adherence, there is a growing shift toward telehealth exercise-based programs. Alongside, passive heat therapy is gaining attention as an alternative approach to induce physiological adaptations, especially for individuals unable to exercise. However, heat therapy may reduce perceived effort, complicating actual assessment of physiological strain in telehealth settings. We assessed the relationship and agreement between physiological and perceptual strain in twelve older men (median age: 68 years) during intermittent exercise (three, 30-minute cycling bouts at increasing rates of metabolic heat production of 150, 200, and 250 W·m-2, each separated by 15 minutes of rest) in the heat (40°C) before and after 7 consecutive days of warm-water immersion (~40°C), with core (rectal) temperature clamped at ~38.5°C for 60 minutes. Physiological strain (PSI) was indexed from core temperature and heart rate and adjusted for skin temperature (aPSI) while perceptual strain (PeSI) used rating of perceived exertion and thermal sensation. Linear mixed models assessed the relationship, and Bland-Altman analysis quantified the agreement between measures (mean bias (95% [LoA]). PSI and aPSI increased with perceptual strain (P<0.001) and were not influenced following acclimation (P>0.610). Similarly, the agreement between physiological and perceptual strain was not affected by passive heating (PSI: -0.4 AU; aPSI: -0.8 AU), but the 95% LoA were wide (PSI: [-4.1 to 3.0 AU]; aPSI: [-4.5 to 2.9 AU]). Although physiological and perceptual strain are linearly related, individual variability may limit the utility of perceptual indices as surrogate markers of physiological strain in older adults during exercise. ClinicalTrials.gov identifier: NCT05838612.

Several randomized clinical trials have been undertaken to evaluate the effect of vitamin D supplementation on reducing the risk of cardiovascular disease (CVD) or CVD mortality; however, mixed results have been reported. The objective of this analysis is to quantify the effect of vitamin D supplements on CVD events and CVD mortality in adults. PubMed, the Cochrane Library and ClinicalTrial.gov were searched for randomized placebo-control trials on adults using common keywords related to vitamin D and CVDs. Two reviewers independently extracted data. The risk of bias was assessed using the Cochrane tool. Data analysis was done using Comprehensive Meta-Analysis V2 (Biostat, Englewood, NJ, USA) to calculate risk ratio (RR) and 95% confidence interval (95%CI). The systematic review and meta-analysis have been registered at PROSPERO (CRD42020165293). One thousand two hundred twenty four abstracts were retrieved, of which 9 (compromising 114 379 participants) were used. This analysis reveals that compared with placebo, vitamin D did not reduce any CVD events (RR = 0.95, 95%CI: 0.88-1.04), CVD mortality (RR = 1.04, 95%CI: 0.871-1.242), myocardial infarction event (RR = 0.96, 95%CI: 0.83-1.11), or myocardial infarction mortality (RR = 1.527, 95%CI: 0.828-2.816). Current evidence does not support the use of vitamin D for the prevention of major cardiovascular events. PROSPERO Registration Number: (CRD42020165293).

Indirect calorimetry has been established as the gold standard to measure resting metabolic rate (RMR); however, its clinical use is limited and can be very expensive. Therefore, the use of predictive equations are commonly used as an alternative. The objective of the current study was to compare RMR calculated using predictive models versus measured RMR using indirect calorimetry among African-Americans. African-American men and women, aged 21-70 years participated in the study. Participants were required to attend two study visits for the collection of self-reported and objective measurements of physical activity. Objective measures of physical activity were measured by accelerometer and self-reported physical activity was obtained using the International Physical Activity Questionnaire Long Form (IPAQ-LF). Objective measures of weight were measured using an automatic scale and height by stadiometer. Harris-Benedict, Nelson, Cunningham, Mifflin-St. Jeor, Owen and WHO/FAO/UNU models were used to measure RMR. All statistical analyses were conducted using R (version 4.3.3). The agreement between measured RMR and predicted RMR from the commonly used equations was assessed using the Bland-Altman method. The study comprised 64 African-American women (n = 43, 67.2%) and men (n = 19, 29.7%), with a mean age of 55.6 years. The WHO/FAO/UNU weight-and-height (bias = 20.5 kcal/day; 95% CI: -92.8 to 133.7; p = 0.719) and WHO/FAO/UNU weight-only equations (bias = 22.7 kcal/day; 95% CI: -90.2 to 135.7; p = 0.688) demonstrated the smallest, non-significant. The WHO/FAO/UNU model was more reliable than other models for predicting RMR among African-Americans.

Recent work has shown that blood flow restriction (BFR) during high-load resistance exercise may be able to acutely augment maximal strength and power, an effect that some hypothesize to be due to a rebound effect from a cuff inflated to a high pressure. However, less known is the role of high pressure independent of any such rebound effect. The objective of this study was to determine whether high-pressure BFR acutely influences strength and power during a concentric-only muscle action. Twenty-five resistance-trained individuals (14 males and 11 females) enrolled in a replicate cross-over trial, in which three paired cycles were completed (i.e., six experimental visits). Each paired cycle involved two visits that were completed in a random order and consisted of maximal strength and power testing (i.e., three maximal concentric knee extension repetitions for both) at either 150% of resting arterial occlusion pressure (150% AOP) or 2 mmHg (sham). Both peak torque (-17 (95% confidence interval (CI): -22.0, -12.7) Nm) and power (-33.9 (95% CI: -46.7, -21.2) W) decreased during the high-pressure BFR condition compared to the sham. Our results suggest that the previous acute strength and power benefits observed with high-load contractions likely are not explained by an independent pressure effect. No acute improvements in strength or power were observed in this investigation. The reason for the reduction in performance in the current study is not known, but we speculate that it may be related to the discomfort associated with contracting under high pressure.

This study examined post-occlusive reactive hyperemia (PORH) and muscle metabolic responses via near-infrared spectroscopy-vascular occlusion tests (NIRS-VOT) under four experimental conditions: (1) rating of perceived exertion (RPE)-Clamp, (2) blood flow restriction (BFR), (3) NON-BFR, each involving low-intensity, sustained isometric forearm flexion, and (4) PASSIVE BFR, a passive occlusion without exercise. Eighteen healthy young adults (11 males, 7 females) completed a sequence of pre-VOT, an experimental intervention, and post-VOT on separate days. During each intervention, time to task failure (TTF), percent changes in muscle oxygenation (SmO₂), and performance fatigability (PF) were also assessed. RPE-Clamp exhibited a significant, positive change in SmO₂ compared to negative changes in other conditions (p < 0.003). PF did not differ between NON-BFR and BFR (p = 1.000), but both were greater than RPE-Clamp and PASSIVE BFR, with RPE-Clamp greater than PASSIVE BFR (p = 0.022). No differences were observed in TTF across conditions (p = 0.455). Desaturation rate (oxygen extraction rate; slope 1) (p < 0.001) and ischemic stimulus (MinSmO₂) (p = 0.001) were greater pre- than post-VOT. Reperfusion slope (slope 2) showed no significant differences by time (p = 0.119) or condition (p = 0.448). Peak SmO₂ (MaxSmO₂) was higher pre- than post-VOT (p = 0.017), with NON-BFR (p < 0.001) and BFR (p = 0.005) greater than PASSIVE BFR. Area under the curve (AUC) above baseline SmO₂ did not differ by time (p = 0.695) but was greater in NON-BFR than PASSIVE BFR (p = 0.010). Despite the distinct SmO₂ responses and fatigue profiles across conditions, immediate post-intervention occlusion following prolonged isometric exercise or occlusion may have reduced oxygen extraction capacity and facilitated metaboreflex-induced sympathetic overactivity, collectively attenuating PORH.

Recent guidance has advocated the use of electric fans as a simple and sustainable cooling strategy to safeguard older adults during exposure to extreme heat. While we showed that fans have negligible impacts on core temperature during daylong (8 h) heat exposure (36 °C, 45% relative humidity (RH)), their impact on cellular responses and potential contribution to heat-induced cellular vulnerability in older adults remains unknown. We assessed 18 participants (8 females, median age 72 (IQR, 67-76) years) exposed to three heat exposures (8 h, 36 °C, 45% RH) with either no fan (control), or with fans generating air speeds of 2 m/s, or 4 m/s directed at the front of the body. Rectal temperature was measured continuously, while proteins associated with autophagy, the heat shock response, acute inflammation, and apoptotic signaling were measured before and after each exposure in peripheral blood mononuclear cells. We observed signs of autophagic dysfunction as indexed via elevations in p62 and pULK1/ULK1 from baseline in each condition; however, responses were not different between conditions (p ≥ 0.077). Further, while fan use did not alleviate elevations in rectal temperature or prevent observations of autophagic dysfunction compared to control, fan use at 4 m/s elicited significant elevations in apoptotic protein cleaved-caspase-3 (mean difference: +0.69 relative quantity, p = 0.033), potentially attributed to elevated serum osmolality (+2.6 mOsm/L, p = 0.020). Therefore, fan use at high settings during heatwaves may be ineffective at alleviating autophagic dysfunction and can potentially incur greater cellular stress in older adults. ClinicalTrials.gov identifier NCT05695079.

Neurophysiological differences between sexes are well-documented; males generally exhibit greater maximal strength and a greater number of recorded motor units (motor unit yield) compared to females, especially in surface electromyography recordings. This disparity in motor unit yield has been attributed to greater subcutaneous tissue thickness in females, which can affect electromyography signal quality. This study aimed to evaluate sex-related differences in the number of recorded motor units and subcutaneous tissue thickness, and to investigate the relationships between recorded motor unit yield, and each of subcutaneous tissue thickness, and maximal voluntary contraction force. Participants (16 F, 15 M) performed isometric dorsiflexion contractions at 20%, 40%, 60%, 80%, and 100% of maximal voluntary contraction force. Subcutaneous tissue thickness was measured using ultrasound, concurrently with surface electromyography from the tibialis anterior. Results indicated no significant difference in the number of identified motor units between males and females at any contraction intensity (p ≥ 0.06). However, males demonstrated a higher maximal voluntary contraction (p < 0.001), and females exhibited greater subcutaneous tissue thickness (p < 0.001). No significant relationships between subcutaneous tissue thickness and motor unit yield, or between maximal voluntary contraction force and motor unit yield, were observed.

This study investigated the performance, physiological, and anthropometric changes in a 28-year-old female following an 1130 km Antarctic ski expedition. Data showed that the participant performed low-intensity ski trekking (LIST, ∼62% maximal heart rate) ∼9 h·day^-1 for 46 days of the total of 49 expedition days. Estimations indicated that the mean energy intake during the trek (∼15 MJ·day^-1/∼3589 kcal·day^-1) was ∼75% greater than that prior to the event (∼8.6 MJ·day^-1/∼2048 kcal·day^-1), and dietary energy distribution of carbohydrates, fats, and proteins changed from a ∼53/30/17 ratio pre-expedition to a ∼43/48/9 ratio during it. Body mass decreased by 11%, while lean mass was maintained. Time to exhaustion during a short (∼5 min) and long (>40 min) incremental ski trek simulation on a treadmill increased by 29% and 3.6%, respectively. Absolute V̇O_2max (L·min^-1) was unchanged, but relative V̇O_2max (mL·kg^-1·min^-1) increased by 17%. Blood glucose concentration decreased by 8.5%, while lipid levels increased by 11%-35%. Creatine kinase, aspartate aminotransferase, and alanine aminotransferase decreased by 21%, 18%, and 13%, respectively. Thyroid stimulating hormone (TSH) increased by 59%. In conclusion, medium-term prolonged LIST can lead to weight-induced endurance performance enhancement and may improve muscle cell resiliency. A low protein intake during such an event does not appear to affect lean mass negatively, despite a substantial weight loss. Reduced carbohydrate consumption and increased fat intake in relative (%) terms during a medium-duration ski trek can decrease blood glucose concentration and raise lipid levels, respectively. TSH may remain elevated several days after such an expedition, reflecting raised metabolism.