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

The present study aimed to compare peak oxygen uptake (V̇O₂peak), peak heart rate (HRpeak), and peak O₂pulse during an incremental and a verification test performed on the same day in hand-cyclists with spinal cord injury (SCI). Eight competitive SCI hand-cyclists (age: 23 ± 2.7 years; V̇O₂peak: 36.3 ± 14.0 mL.kg^-1.min^-1) performed a maximal incremental handcycling test and a verification test to exhaustion at 100% of the peak speed on an oversized treadmill. The V̇O₂peak, HRpeak, and peak O₂pulse (i.e., VO₂/HR) were compared between incremental and verification tests. Absolute and relative V̇O₂peak obtained in the verification test (2.51 ± 0.96 L.min^-1; 36.3 ± 14.0 mL.kg.min^-1) were significantly higher than values obtained in the incremental test (2.24 ± 0.79 L.min^-1; 33.5 ± 12.9 mL.kg.min^-1; P < 0.05). The mean differences (95% CL) of absolute and relative V̇O₂peak between tests were 8.2% (3.3%-13.2%) and 10.9% (4.3%-18.1%), respectively. There was no difference in HR peak (incremental: 169 ± 24 bpm; verification 167 ± 25 bpm; P = 0.130). Peak O₂pulse from the verification test (14.6 ± 4.7 mL.beat^-1) was higher than incremental test (13.0 ± 3.8 mL.beat^-1; P = 0.007). In conclusion, the verification test elicited greater V̇O₂peak and O₂pulse than a two-phase incremental test despite the similar HRpeak. This indicates that for this progressive protocol lasting ≥25 min, the verification phase adds value to determining V̇O₂peak in SCI athletes.

Motor unit firing rate (MUFR) and pennation angle were measured concurrently in males and females from submaximal to maximal intensities. Thirty participants, (16 female, 14 male) performed isometric dorsiflexion contractions at 20%, 40%, 60%, 80%, and 100% of maximal voluntary contraction (MVC). During each contraction, measures of MUFR were obtained via surface electromyography decomposition, and muscle fiber pennation angle and fascicle length were obtained via ultrasound. There was no significant interaction effect of sex and contraction intensity present for mean MUFR (p = 0.24), pennation angle (p = 0.98), or fascicle length (p = 0.81). Males had greater mean MUFR (p < 0.001), pennation angle (p = 0.02), and fascicle length (p = 0.03) compared to females. In general, mean MUFR (p < 0.001) and pennation angle (p < 0.02) increased with increasing contraction intensity; however, fascicle length (p = 0.30) was similar across contraction intensities. There were no significant relationships between mean MUFR and pennation angle for males (r = 0.18, p = 0.13) or females (r = 0.20, p = 0.09), nor between mean MUFR and fascicle length for males (r = 0.20, p = 0.10) or females (r = 0.21, p = 0.07). Although sex-related differences in MUFR, pennation angle, and fascicle length were present, there were no relationships between MUFR and the muscle properties. These results suggest that sex-related differences in mean MUFR may not be associated with the sex-related differences in the muscle architectural properties currently investigated.

Plant-based meat alternative (PBMA) consumption has increased amid significant reformulation efforts. Although reformulated PBMAs have characteristics that could provide cardiometabolic benefits over animal proteins (e.g., higher fiber, certain phytochemicals/micronutrients), their acute health effects remain unclear. Moreover, whether baseline adiposity (i.e., normal weight or overweight/obesity) affects the response to PBMA intake is unknown. We conducted a randomized crossover study where healthy participants (N = 30) with a normal body mass index (BMI; 18.5-24.9 kg/m²; n = 15) or overweight/obese BMI (>25.0 kg/m²; n = 15) consumed two high-fat meals on separate occasions containing a reformulated PBMA (Beyond Meat Cookout Classic^TM) or similar beef product (80% lean ground beef). Meals were matched for energy (950 kcal) and macronutrient matched (71 g fat/31-35 g carbohydrate/41-42 g protein). At each trial, an intravenous catheter was inserted and biomarkers of inflammation (i.e., interleukin (IL)-6, tumor necrosis factor (TNF)-α), intestinal permeability (i.e., lipopolysaccharide binding protein (LBP), soluble CD14 (sCD14), LBP:sCD14 ratio), and metabolic factors (triglycerides, HDL-C, glucose) were measured at baseline and hourly for 4 hours post-meal. Paired t tests and two-way mixed model ANOVAs were used to examine within-meal-condition changes and differences in incremental area under the curve (iAUC) across meal and BMI conditions, respectively. Regardless of protein source, high-fat meals increased IL-6, TNF-α, LBP, sCD14, LBP:sCD14, and triglycerides and decreased HDL-C (p ≤ 0.01). In BMI subgroup analyses, an interaction effect for IL-6 iAUC was observed (p_MealxBMI < 0.05), but post hoc analyses were not significant (p ≥ 0.07). Overall, inclusion of a reformulated PBMA within a high-fat meal resulted in a similar cardiometabolic response to a nearly identical meal containing animal protein (ClinicalTrials.gov:NCT06445296).

The objective of this study was to develop and evaluate a food choices assessment score (FCAS) measuring alignment with 2019 Canada's Food Guide (CFG) and Canada's Dietary Guidelines (CDG) using a non-quantitative food frequency questionnaire (FFQ) data. Cross-sectional data from the Canadian Health Measures Survey (2016-2019), including 6459 participants (≥19 years) and a non-quantitative FFQ (∼100 food items) were used. Content and construct validity and assessing reliability were used to evaluate the FCAS, including a comparison of mean FCAS among Canadian subgroups, calculating the FCAS for high quality diet menus, investigating the consistency of the FCAS with the Dietary Approaches to Stop Hypertension (DASH), as a healthy diet linked with lower cardiometabolic risks, and estimating Cronbach's alpha for reliability. The FCAS consisted of nine components for a total of 80 points. The FCAS captured the key recommendations of the 2019 CFG/CDG. Mean (SE) FCAS of the adult Canadian population was 29.3 (0.4) (/80) and was higher in females 32.2 (0.4) and non-smokers 30.3 (0.3) compared to males 26.7 (0.4) and smokers 23.6 (0.9), respectively (p < 0.0001). FCAS yielded high scores for healthy menu samples of CDG (80/80) and DASH (70/80) diets. FCAS was correlated with DASH diet score (r = 0.83). Cronbach's alpha was found to be moderate (0.5), as expected, which confirmed the multidimensionality of the FCAS components in reflecting different characteristics of diet quality. These analyses suggest adequate validity with multidimensional consistency of the 2019 CFG/CDG FCAS as a new tool for use with non-quantitative FFQ data.

High-intensity exercise increases inflammation and elicits leukocytosis but may also increase infection risk. Interestingly, females have higher cell-mediated immunity than males. Sex hormones fluctuate across the menstrual cycle (MC), and the luteal phase has been linked to a more pro-inflammatory environment than the follicular phase. This study investigated whether white blood cell (WBC) count and WBC differential (i.e., neutrophils, lymphocytes, monocytes, eosinophils, and basophils) differed across two MC phases following an acute bout of exercise that varied in intensity. Eight regularly menstruating females (age = 21.6 ± 3.0; BMI = 20.9 ± 4.1 kg/m²) completed a $\dot{V}{\text{O}}_2$ peak (37.8 ± 11.0 mL/min/kg) test and two 40 min cycling exercise trials (30 min of moderate intensity (%HRmax = 71.13 ± 8.5, % $\dot{V}{\text{O}}_2$ peak = 49.8 ± 21.6) and ∼10 min of high intensity (%HRmax = 93.3 ± 6.7, % $\dot{V}{\text{O}}_2$ peak = 75.4 ± 27.6)) 14 ± 2 days apart. Blood samples were taken pre- and post-moderate-intensity exercise (30 min), as well as immediately post-high-intensity exercise (∼40 min). Both moderate- and high-intensity exercise increased WBC counts (p < 0.01, (d = 1.11 and 1.34, respectively)). More specifically, neutrophil counts increased following both moderate (p < 0.05, d = 0.72) and high (p < 0.01, d = 0.95) exercise intensities. However, lymphocytes (p < 0.01, d = 1.15) and monocytes (p < 0.01, d = 0.99) were only elevated following high-intensity exercise. MC phase did not significantly alter WBC counts nor differentials, although there were trends observed towards greater leukocytosis at moderate-intensity exercise during the luteal phase. These results demonstrate that in some cases moderate-intensity exercise increased leukocytosis (in particular, neutrophils), while high-intensity exercise resulted in significant leukocytosis primarily as a result of increased neutrophils, lymphocytes, and monocytes. Future research should investigate this relationship in a larger sample observing inflammatory cytokines and WBC function/activity with the inclusion of a group in the early follicular phase.

Irisin, an adipo-myokine, is positively associated with cardiorespiratory fitness and negatively associated with type 2 diabetes mellitus (T2DM). However, it is unclear if individuals with longer or shorter durations of T2DM express the same irisin levels following exercise. The objective of this study is to investigate the impact of 28 weeks of moderate-to-vigorous intensity aerobic exercise on irisin levels in individuals with short- and long-duration T2DM. This secondary analysis included participants (n = 34) aged ≥ 19 years old with T2DM who completed 28 weeks of aerobic exercise training for 150 min per week at a moderate-to-vigorous intensity-16 weeks at a moderate intensity (4.5 metabolic equivalents of tasks (METs)) and then randomized to 12 weeks of maintained-intensity (4.5 METs) or increased-intensity (6.0 METs) aerobic exercise. Participants were categorized into two groups: (1) short-duration T2DM (<10 years) or (2) long-duration T2DM (≥10 years). Irisin was analyzed using enzyme-linked immunosorbent assay and western blotting techniques. All measurements were performed at baseline, 16 weeks, and 28 weeks. A significant time × T2DM duration group interaction (F(2) = 8.062, p < 0.01) was observed with 28 weeks of moderate-to-vigorous intensity aerobic exercise. Western blot analysis revealed a 1.37-fold increase in plasma irisin expression (p = 0.03) in the long-duration increased-intensity group and no change in irisin expression (p > 0.05) in the maintained-intensity groups of short and long duration. The results of this analysis suggest that 28 weeks of moderate-to-vigorous intensity aerobic exercise differently impacted plasma irisin in individuals with short- or long-duration T2DM. The Improving Individual Glycemic Response with Exercise Intensity (INTENSITY) study was registered at clinicaltrials.gov (NCT03787836).

We assessed how different levels of breast support affected exertional symptoms and respiratory responses in small- and large-breasted females during treadmill exercise. Twenty recreationally-active females (mean ± SD age: 22 ± 2 years) were divided into small (SBV: 322±77 mL) and large breast volume (LBV: 580±88 mL; p < 0.001, g = 2.98) groups. Participants completed three 5 min bouts of treadmill exercise at 30%, 60%, and 90% of individual peak power output (PPO)-corresponding to walking, low-intensity running, and high-intensity running-wearing either a high-support or low-support sports bra (randomized). Measurements included cardiorespiratory variables, operating lung volumes, inspiratory muscle electromyographic, respiratory muscle pressures, breast acceleration, and exertional symptoms (breathlessness, chest tightness due to bra). High- versus low-support sports bras reduced mean breast acceleration (p < 0.001, ${\eta }_p^2$ =0.55), but evoked higher ratings of chest tightness (p = 0.040, ${\eta }_p^2$ =0.16) in LBV participants at low- and high-intensity running (g = 1.09 and g = 0.99, respectively). Although breathlessness was not significantly different by bra or breast volume (all p > 0.05), LBV participants consistently reported breathlessness intensity and unpleasantness ≥ 1 Borg unit (BU) higher than SBV participants during low- and high-intensity running (breathlessness intensity: ∼5 vs. ∼3 BU at 60% PPO; ∼9 vs. ∼7 BU at 90% PPO; breathlessness unpleasantness: ∼4 vs. ∼2 BU at 60% PPO, ∼8 vs. ∼6 BU at 90% PPO). There were no differences in cardiorespiratory variables, inspiratory muscle activity, operating lung volumes between breast volume groups or sports bras (all p > 0.05). We emphasize the importance of addressing subjective discomfort, including chest tightness and breathlessness, when developing effective breast support for weight-bearing exercise, especially for larger-breasted individuals.

With climate warming, there is an urgent need to understand the health effects of occupational heat exposure. This systematic review examined the cumulative effects of consecutive days of prolonged physical work or activity on heat strain and physical performance. Electronic databases MEDLINE, SPORTDiscus, PsychInfo, and Academic Search Complete were searched until July 2024 with terms related to work, consecutive days, and heat. Studies were included if they involved ≥4 h of physical work/activity on ≥2 consecutive days, and included a measure of heat strain (e.g., core temperature) or physical performance (e.g., repetitions). After removing duplicates, 6030 studies were screened (title and abstract), 133 progressed to full-text screening, and 33 met the inclusion criteria with risk of bias assessed. However, only five studies used standardized environmental and work conditions across days. Synthesis of the cumulative effects (without meta-analysis) was therefore restricted to these studies. None observed a cumulative impact on heat strain, as indexed by a higher core temperature or heart rate compared to day 1. None reported a reduction in physical task performance across days. These findings indicate that the cumulative effects of occupational heat exposure on heat strain and physical task performance were minimal, although evidence supporting this conclusion is sparse. PROSPERO registration: CRD42023452936.