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

Dual-energy X-ray absorptiometry (DXA) is more available than gold-standard magnetic resonance imaging (MRI), but DXA ability to estimate abdominal skeletal muscle mass (SMM) is unknown. DXA-derived abdominal fat-free mass (FFM; Hologic QDR2000 or QDR4500w) was correlated with single-slice MRI SMM at L4 (N = 69; r QDR2000 = 0.71, QDR4500w = 0.69; p < 0.0001). Linear regression to predict SMM, including DXA FFM, BMI, and age, resulted in an R-squared of 0.72 and 0.65 for QDR2000 and QDR4500. Bland-Altman limits of agreement were ±21 and ±31 g for 2-3 standard deviations from the mean difference. DXA predicted abdominal SSM is a moderate proxy for MRI abdominal SMM.

Novelty: This study is novel in classifying bodybuilding posing training as vigorous intensity exercise using metabolic equivalents (METs) and heart rate (HR) responses. It provides empirical evidence showing that posing training meets the vigorous intensity benchmarks, with METs and %HRmax values comparable to established vigorous exercise standards. The research highlights the novel finding that stimulant usage and the peak week phase of preparation significantly influence physiological responses and perceived exertion in bodybuilders. Specifically, athletes using stimulants and those in peak week displayed higher ratings of perceived exertion (RPE) and maximum heart rates, indicating that these factors notably affect the intensity and perceived difficulty of posing training.

Debate over whether to promote high-intensity interval training (HIIT) in public-health contexts has centred on assumptions that people will have negative psychological responses to HIIT, leading to poor adoption and adherence. We challenge these assumptions through reviews of (1) studies that have measured psychological responses to HIIT and (2) studies that have measured adherence to HIIT protocols in supervised or unsupervised settings. Overall, the evidence suggests that HIIT is just as enjoyable as moderate-intensity continuous training (MICT). In supervised situations, on average, adherence is similarly high for HIIT and MICT (>89%). In unsupervised situations, adherence is similarly lower for both HIIT and MICT (<69%). Based on these findings, we recommend that attention be directed toward improving behaviour-change and maintenance for all types of exercise. Resources are better spent addressing fundamental questions about exercise initiation and adherence, than perpetuating a vitriolic and uncivil debate over the value of HIIT versus MICT. We discuss how debate, incivility, and bullying undermine scientific progress and we issue a call for respectful, civil dialogue in academic HIIT discussions. We conclude with recommendations that can be used by all members of the scientific community to practice, champion, and defend civil discourse.

Blood properties influence aerobic exercise performance. While vascular volumes and hemoglobin mass (Hb_mass) are elevated in trained individuals, evidence of sex differences in vascular volumes is equivocal due to inadequate matching of aerobic fitness between males and females. This cross-sectional study aimed to compare hematological values normalized to body mass (BM) and fat-free mass (FFM) between males (n = 45) and females (n = 34) matched for aerobic fitness (V̇O₂max) normalized to FFM (mL∙kg FFM^-1∙min^{- 1}). Data included body composition measured by dual-energy X-ray absorptiometry (DXA), V̇O₂max from an incremental test, and hematological values derived from a CO rebreathe test. Fat mass was unrelated to blood volume (BV; R² = 0.02, P = 0.26) and Hb_mass (R² = 0.03, P = 0.16), while FFM was the strongest predictor of both (R² = 0.75 and R² = 0.83, respectively, P < 0.001). Females exhibited higher FFM-normalized BV (+4%, P < 0.05) and plasma volume (PV) (+14%, P < 0.001) and lower red blood cell volume (RBCV) (-8%, P < 0.001) and Hb_mass (-8%, P < 0.001) compared to males. Positive correlations between aerobic fitness and relative Hb_mass and BV were observed in both sexes when normalized to BM and FFM (0.48 < r < 0.71; P < 0.003). Stepwise multiple regression models, including FFM, V̇O₂max, height, and [Hb], provided accurate predictions of Hb_mass (R² = 0.91) and BV (R² = 0.85). Overall, sex differences persist in relative Hb_mass, BV, PV, and RBCV after matching of aerobic fitness, though relative BV and PV were greater in females. These findings suggest sex-specific strategies in oxygen delivery and/or extraction, and they underscore the importance of carefully selecting normalization practices when assessing sex-based differences in hematological variables.

The effects of acute dehydration on neuromuscular function have been studied. However, whether the mechanisms underpinning such function are central or peripheral is still being determined, and the results are inconsistent. This systematic review aims to elucidate the influence of acute dehydration on neuromuscular function, including a novel aspect of investigating the central and peripheral neuromuscular mechanisms. Three databases were used for the article search: PubMed, Web of Science, and Scopus. Studies were included if they had objective measurements of dehydration, muscle performance, and electromyography data or transcranial magnetic stimulation or peripheral nerve stimulation measurements with healthy individuals aged 18-65 years. Twenty-three articles met the eligibility criteria. The studies exhibited considerable heterogeneity in the methods used to induce and quantify dehydration. Despite being inconsistent, the literature shows some evidence that acute dehydration does not affect maximal strength during isometric or moderate-speed isokinetic contractions. Conversely, acute dehydration significantly reduces maximal strength during slow-speed isokinetic contractions and fatigue resistance in response to endurance tasks. The studies report that dehydration does not affect the motor cortical output or spinal circuity. The effects occur at the peripheral level within the muscle.

Maternal exercise is beneficial for offspring brain development. Amyloid precursor protein (APP) influences neurogenesis and synaptic plasticity. Cleavage products of APP are implicated in the proliferation of neural progenitor cells and neuronal network development. Our study aimed to investigate differences in APP processing in active or sedentary offspring of dams who were exposed to voluntary wheel running with and without a western diet throughout gestation. Female Wistar rats (7-8 weeks old) were fed a normal chow or western diet and randomized into voluntary wheel run or sedentary conditions. Dams returned to sedentary conditions post-parturition. The pups were weaned at 6 weeks after which point half of the samples were collected, while the rest of the pups remained on a normal diet, separated into sedentary or voluntary wheel run groups, and collected 12 weeks later. In utero exposure to maternal exercise was associated with higher neuronal nuclear protein, higher soluble APPα and lower soluble APPβ in offspring prefrontal cortex tissue at 6, but not 18 weeks of age. Neuronal nuclear protein is exclusive to mature neurons implying that offspring of mothers who exercised could have more neuron maturation potentially influenced by the higher APPα content at this early developmental stage. The voluntary wheel run offspring groups had a higher mature/pro brain derived neurotrophic factor ratio compared to the sedentary counterparts. The maternal effects were isolated to the juvenile 6-week-old pups, while the differences in the adult offspring were caused by their own exercise status.

Nearly 20 years have elapsed since the first clinical trial investigated the impact of interval training on patients with cardiovascular disease (CVD). This clinical corner discusses the health outcomes of systematic reviews and meta-analyses and appropriately powered randomized controlled trials (RCTs) which have tested these interval training programs across various CVDs (i.e., coronary artery disease, heart failure, atrial fibrillation, peripheral arterial disease, and cardiac implantable electronic devices). The publications included in this clinical corner have shown that interval training leads to similar or superior improvements in V̇O2peak, functional capacity, pain free walking, QoL, anxiety, depression, and endothelial function, but the magnitude of improvements across varying protocols (e.g., length and number of work periods, intensities of work periods, duration of exercise sessions, frequency of exercise sessions, duration of program) and optimal dosage for males and females is unclear across CVD conditions. The heterogeneity in protocols, physical and mental health outcome measures, and lack of sex- and gender-based analyses calls for more high-quality research in this area.

Food literacy is a growing area of interest given its potential to support healthy and sustainable diets. Most existing food literacy measures focus on nutrition and food skills but fail to address food systems and socio-environmental aspects of food literacy. Further, measures developed and tested in the Canadian context are lacking. The objective of this project was to develop and test the validity and reliability of a brief self-administered measure, in French and English, designed to assess multiple dimensions of food literacy among adults living in Canada. The 23-item Canadian Food Literacy Measure was developed through an iterative process that included assessment of face and content validity through expert review (n = 20) and cognitive interviews (n = 20) and construct validity and reliability, i.e., internal consistency through an online survey (n = 154). The results indicate that the measure is well understood by both English- and French-speaking adults. The measure's construct validity is demonstrated by the observed differences in total scores in hypothesized directions by gender (p = 0.003), age (p = 0.007), education level (p = 0.002), health literacy (p < 0.001) and smoking status (p = 0.001), and the significant positive correlation (r = 0.29; p = 0.002) between total scores and fruit and vegetable intake. The measure also has high internal consistency with a Cronbach's coefficient alpha of 0.80. This measure can be used in surveillance studies to provide insight into the food literacy of adults living in Canada and in epidemiologic research that aims to explore how food literacy is associated with a variety of health outcomes.

Exercise has long been known for its beneficial effects on insulin sensitivity (IS) and glucose handling with both moderate-intensity continuous (MIC) exercise and resistance exercise (RE) inducing beneficial effects. In recent years, low-load, high-repetition (LLHR) RE has emerged as a strategy to increase muscle mass and strength to levels similar to traditional RE; however, the effects of LLHR RE on glucose handling has yet to be investigated. The purpose of this trial was to compare the acute effects of LLHR RE to MIC exercise on post-exercise glycemic control and insulin sensitivity in males and females. Twenty-four (n = 12/sex) participants completed acute bouts of MIC exercise (30 min at 65% V̇O₂_peak) and LLHR (3 circuits, 6 exercises/circuit, 25-35 repetitions/exercise/circuit) matched for time with muscle biopsies immediately pre and post exercise and an oral glucose tolerance test (OGTT) 90 min following exercise. Blood glucose concentrations (p = 0.002, η_p ² = 0.37), glucose AUC (p = 0.002, η_p ² = 0.35) and max glucose concentration (p = 0.003, η_p ² = 0.34) were lower during the post exercise OGTT following LLHR RE compared to MIC exercise. There was a main effect of trial on TBC1D1 Ser²³⁷ phosphorylation (p = 0.04, η_p ² = 0.19) such that it was greater following MIC exercise compared to LLHR RE. Furthermore, phosphorylated ACC Ser⁷⁹ increased following MIC exercise with no change following LLHR RE (p < 0.001, η_p ² = 0.50). Phosphorylation of PTEN Ser³⁸⁰ was greater in males than females during LLHR RE (p = 0.01, η_p ² = 0.27). These findings suggest that LLHR RE is a feasible exercise modality to improve post-exercise glycemic control in both males and females. Trial registration number: NCT06217679.

To examine the effects of 7-days juçara powder (JP) intake on oxidative stress biomarkers and endurance and sprint cycling performances. In a randomized, placebo-controlled, crossover, and triple-blind study, 20 male trained cyclists were assigned to intake 10 g of JP (240 mg anthocyanins) or placebo (PLA) for 7 days and performed a cycling time-to-exhaustion (TTE). A 5 s cycling sprint was performed before and after the cycling TTE. Blood oxidative stress biomarkers and lactate concentration where evaluated 1 h before (T-1), immediately after (T0), and 1 h after (T1) the cycling TTE. The mean duration time for the cycling TTE was 8.4 ± 6.0% (63 ± 17 s) longer in the JP condition (JP: 751 ± 283 s) compared to PLA (688 ± 266 s) (P < 0.019). Two-way repeated measures Analysis of variance showed an increase in the JP condition for reduced glutathione (GSH) (P = 0.049) at T0 (P = 0.039) and T1 (P = 0.029) compared to PLA with a moderate effect size at T0 (d = 0.61) and T1 (d = 0.57). Blood lactate levels increased over time in both conditions (P ≤ 0.001). No differences were observed for the post-TTE sprint fatigue index, total phenols, protein carbonyls, and glutathione peroxidase activity. Seven-day intake of JP improved cycling endurance performance and increased GSH levels but had no effect on lactate and cycling sprint-induced fatigue.