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

Our previous study revealed a significant anti-atherosclerotic effect of Kgengwe seed powder (KSP) in low-density lipoprotein receptor knockout (LDL-r-KO) mice. The importance of various lipid and protein metabolites, including certain amino acids and fatty acids on atherogenesis has been well established. Thus, we used plasma and fecal samples from our previous study to further study the association of such metabolites with atherosclerotic lesion development. Male LDL-r-KO mice were provided with an atherogenic diet supplemented with (treated, n = 10) or without (controls, n = 10) 10% (w/w) KSP for 20 weeks. The treated group showed significantly (P < 0.05) higher plasma levels of many amino acids plus propionic acid, indoleacetic acid, pyruvic acid, beta-hydroxybutyric acid, alpha-ketoglutaric acid, trimethylamine N-oxide, LYSOC16:0, LYSOC18:0, and LYSOC18:2, as compared with those of the control group. Similarly, several oxylipins, including 15-keto prostaglandin E2, 9,10,13-trihydroxy-octadecenoic acid, 9,10-epoxy-octadecenoic acid, and 12,13-epoxy-octadecenoic acid increased by approximately 2.0 log2 folds (P < 0.05) in the plasma of the treated group. Other oxylipins, including 15,16-epoxy- octadecadieonic acid, 13-hydroxy-octadecadienoic acid, and prostaglandin E2 showed also an increased level, but to a lesser extent. Furthermore, our findings showed a significant positive correlation between plasma concentrations of prostaglandin E2 and IL-10 in the treated mice. We also observed a significant negative association between atherosclerotic lesion size and plasma levels of citrulline, lysine, alpha-ketoglutaric acid, and 15,16 epoxy-octadecadienoic acid. Additional in vitro and in vivo studies are needed to explore the mechanisms of such associations.

Occupational heat stress poses a major threat to worker health and safety that is projected to worsen with global climate warming. To manage these adverse effects, most industries rely on administrative controls (stay times and work-to-rest allocations) that are designed to limit the rise in body core temperature in the 'average' individual. However, due to the extensive inter- and intra-individual variation in thermoregulatory function, these administrative controls will result in some individuals having their work rate and productivity unnecessarily restricted (false positives), while others may be subject to rises in heat strain that compromise health (false negatives). Physiological monitoring has long been touted as a more effective approach for individualized protection from excessive heat stress. This has led to extensive interest in the use of wearable technology for heat stress management from both the scientific community and manufacturers of wearable devices, which has accelerated in the past decade. In this review, we evaluate the merits of the recent and emerging approaches to manage occupational heat strain with wearable physiological monitors. Against this background, we then describe the issues that we perceive to be unresolved regarding the use of wearable heat strain monitors and the research efforts needed to address those issues. Particular emphasis is directed to the efficacy of existing physiological indicators of heat strain, how to define upper limits for those indicators and the efforts required to rigorously validate emerging wearable heat strain monitoring devices.

The aim of the present study was to test the effects of different doses of anhydrous theacrine (3 and 6 mg.kg-1 of body mass) on 4-km cycling time trial performance. Nineteen (11 men and 8 women) cyclists (30.8 ± 10.0 years, 71.7 ± 11.8 kg, 170.1 ± 9.0 cm, and 17.0 ± 6.2 % of body fat) completed three 4-km cycling time trials after ingesting either placebo, or 3 mg.kg-1 or 6 mg.kg-1 of body mass of theacrine. No significant differences (p < 0.05) were observed in time to cover the 4-km cycling time trial between the placebo, 3 mg.kg-1 of theacrine, and 6 mg.kg-1 of theacrine conditions. However, the intake of theacrine at the dose of 6 mg.kg-1 increased resting systolic and diastolic blood pressure (p < 0.05). Some side effects, such as gastrointestinal discomfort, perception of tachycardia, dizziness, headache, head pressure, hand tremor, and lack of disposition were reported after the ingestion of either 3 or 6 mg.kg-1 of body mass of theacrine. In conclusion, theacrine supplementation does not improve endurance performance and provokes side effects that might restrict its use as a supplement.

Visiting an air-conditioned location during heat exposure reduces physiological strain, however the effects on gastrointestinal barrier dysfunction and renal ischemia remain unexplored. We compared serum protein responses during a 9-h heat exposure (40.3°C, 9.3% relative humidity) in 17 older adults without cooling (control) and 19 older adults with a cooling break (~23°C) during hours 5 and 6 (cooling). IFABP and sCD14 increased similarly across groups. NGAL was 3.2 pg/mL [1.9, 6.1] lower in the cooling group during heat exposure. A 2-h cooling centre exposure did not ameliorate gastrointestinal barrier dysfunction, but did a reduce a surrogate marker of renal ischemia.

Recent evidence from modelling and laboratory-based studies showed that electric fans are ineffective at lowering core temperature in older adults at air temperatures of 36°C. However, their influence on self-reported environmental symptoms and mood-state during daylong use in hot indoor environments remains unclear. Eighteen older adults (8 females, median [interquartile range]; 72 [67-76 years]) completed three randomized 8-hour heat exposures (36°C, 45% relative humidity) with a fan generating air speeds of 0 (no fan, Control), 2, or 4 m/s at the front of the body positioned 1-m away. Participants were seated throughout, except for 4 x 10-min periods of simulated activities of daily living (stepping [~2.25 METs]). Core temperature, mean skin temperature, and heart rate areas under the curve (AUC, hours 0-8) were calculated to assess cumulative physiological strain. Total symptom scores (68-item environmental symptoms questionnaire) as well as total mood disturbance and energy index (40-item profile of mood states questionnaire) were evaluated at end-heating (adjusted for pre-exposure). Core temperature, mean skin temperatures, and heart rate AUCs were not different between conditions (all P≥0.087). Total symptom scores were 0.89-fold [0.81,0.97] lower with fan use (combined across speeds) compared to no fan (P=0.009). Energy index scores were 2.4 points [0.8,4.0] higher with fan use compared to no fan (P=0.004). However, mood disturbance was not significantly different between conditions (P=0.345). Our exploratory analysis show that fans can reduce self-reported symptoms and increase perceived energy levels in older adults in overheated indoor environments, despite no meaningful attenuation of physiological strain.

Exercises focusing on eccentric contractions may stimulate the brain better, improving cognitive function. We tested the hypothesis that executive function and attention would improve more after eccentric resistance exercise (ECC) than stretching exercise (STRETCH) training. Healthy older women (65-75y) underwent either ECC (n=14) or STRETCH (n=14) intervention for 8 weeks. ECC consisted of 7 exercises emphasizing eccentric contractions while STRETCH performed 12 stretching exercises, with supervised sessions undertaken twice weekly accompanied by a home-based program. Executive function and attention were assessed using the Stroop test of color naming (STCN) and conflicting color words, symbol digit modalities test, digit span test (DST), and trail making tests (TMT-A, TMT-B), and 6 physical function tests were undertaken before and after the 8-week training period. Fasting blood samples were obtained before and after the training. A significant (p<0.05) group x time interaction effect was evident for STCN, DST and TMT-A, with only ECC showing improvements (DST:14.7±27% and TMT-A:10.2±12%) from pre- to post-training. No significant changes in other cognitive function tests were found for either group. All physical function tests except one-leg balance test showed greater improvement (p<0.05) for ECC than STRETCH. No significant changes in blood lipid profile and brain-derived neurotrophic factor were found, but serum glucose concentration and glycosylated hemoglobin decreased (p<0.05) in ECC. These results suggest that a short-term eccentric exercise intervention was effective in enhancing components of cognitive and physical function of older women and may prove a useful strategy in combating age-related decline in cognitive and physical function.

Sport participation among older adults, is increasing, but many still fall short of meeting physical activity (PA) guidelines. Master athletes, who engage in PA through systematic training, and competition, offer unique insights into PA practices in later life. This study explored whether master athletes embody the principles of physical literacy and how their experiences could inform strategies to promote PA among older adults. An electronic survey completed by 35 master athletes (55-75 years, 20 female) and follow-up interviews with eight participants revealed that most were unfamiliar with the term "physical literacy," yet they intuitively practiced its principles. Master athletes identified parallels between their behaviors and physical literacy but viewed existing models as primarily youth-focused and less applicable to older adults. Additionally, lifelong sport participation was not universal; nine participants, predominantly women, began competitive sports later in life. A key finding was the importance of social connectedness, which emerged as a critical motivator and enabler for sustained PA among master athletes. This element, largely absent from current physical literacy frameworks, may be vital for engaging older adults in PA. Integrating social connection into physical literacy models could address barriers unique to this demographic, enhancing participation and promoting healthier aging.

Metabolic syndrome (MetS) and short sleep are prevalent health concerns in the United States, yet the relationship between leisure-time physical activity (LTPA) and MetS among individuals with short sleep duration remains unclear. This cross-sectional study analyzed data from 8999 US adults aged 20 years and older in the National Health and Nutrition Examination Survey (NHANES). Short sleep duration was defined as less than 7 hours per night, and MetS was diagnosed based on criteria from the American Endocrine Society and the American Society of Clinical Endocrinology. Weighted regression analyses revealed a significant inverse association between LTPA and MetS, with higher LTPA levels linked to lower MetS [OR (95% CI): 0.990 (0.984, 0.997), p = 0.003]. Participants who achieved the World Health Organization's recommended LTPA levels had a substantially lower MetS compared to those with no LTPA [OR (95% CI): 0.624 (0.527, 0.738), p = 0.001]. Stratified analyses showed that this protective effect varied across demographic subgroups, and a threshold effect was observed at 2000 MET-minutes per week, beyond which further LTPA did not significantly enhance protection against MetS. These findings highlight the importance of regular LTPA is negatively associated with MetS among individuals with inadequate sleep, emphasizing the need for targeted health promotion efforts in this population.

This randomized interventional study aimed to investigate the effect of carnosine-enriched chicken meat consumption on systemic endothelium-dependent and -independent micro- and macrovascular reactivity in thirty-five healthy competitive male athletes. Both forearm skin micro- and macrovascular endothelium-independent vasodilation were increased, and diastolic and mean arterial blood pressure (BP) were decreased in Carnosine group (n=19) following the 3-week dietary protocol. Microvascular endothelium-dependent response (PORH) was increased in the Carnosine group and significantly associated with decreased mean arterial BP level. Following dietary protocol, Controls (n =16) had substantially higher urate (but still normal) levels than the Carnosine group. Carnosine supplementation in the form of functional food enhances endothelium-dependent and vascular smooth muscle-dependent vasodilation in peripheral micro- and microcirculation. Carnosine's effect on vascular endothelium could be attributed to its blood pressure-lowering effect. Results suggest that carnosine has the potential to resist hyperuricemia in healthy individuals. (NCT05723939).

Changes in glucose and insulin are potentially involved in the appetite-regulatory effects of exercise considering their role post-prandially.

Purpose: To examine if glucose and insulin play a role in post-exercise appetite regulation.

Methods: 12 participants (M=8; 26±5 y) completed 3 experimental sessions in a systematically rotated randomized crossover design: 1) no-exercise control (CTRL); 2) moderate-intensity continuous training (MICT; 30-min, 70% maximal oxygen consumption (V̇O2max)); and 3) sprint interval training (SIT; 4 x 30-s "all-out" sprints, interspersed with 4-min rest). Plasma glucose, insulin, acylated ghrelin, active peptide tyrosine tyrosine (PYY), active glucagon-like peptide-1 (GLP-1), and overall appetite perceptions were measured pre-exercise, 0-, 30-, 60-, and 120-min post-exercise. Energy intake was recorded the day before, of, and after experimental sessions.

Results: Glucose was elevated 0-min post-exercise (p<0.097, d>0.52) compared to CTRL with no differences between exercise bouts. Acylated ghrelin was suppressed by MICT (60-, 120-min) and SIT (0-, 30-, 60-, 120-min; p<0.080, d> 0.56) compared to CTRL, while also suppressed in SIT compared to MICT at 30-, 60-, 120-min (p<0.026, d>0.74). GLP-1 was elevated following MICT (0-, 30-, 60-min) and SIT (60-min; p<0.094, d>0.53) compared to CTRL and following MICT compared to SIT (0-min; p=0.005, d=1.03). Overall appetite was suppressed by SIT post-exercise (p<0.058, d>0.61) compared to CTRL and MICT, and by MICT 0-min post-exercise compared to CTRL (p=0.036, d=0.71). There were no exercise effects on insulin, PYY, or free-living energy intake (p>0.217, ηp2<0.130).

Conclusion: Glucose and insulin do not appear to play a role in exercise-induced appetite suppression.