Pub Date : 2024-09-01Epub Date: 2024-05-22DOI: 10.1139/apnm-2023-0485
Alexa Govette, Jenna B Gillen
Limited research has characterized the metabolic health benefits of bodyweight interval exercise (BWE) performed outside of a laboratory setting. Metabolic responses to exercise can also be influenced by meal timing around exercise, but the interactive effects of BWE and nutrition are unknown. This study investigated the effects of BWE performed in the fasted or fed state on postprandial glycemia, post-exercise fat oxidation and appetite perceptions. Twelve females (23 ± 2 years; 22 ± 2 kg/m2) underwent two virtually-monitored trials that involved completing BWE (10 × 1 min, 1 min recovery) 5 min before (FastEX) or beginning BWE 10 min after (FedEX) a standardized breakfast. Heart rate and rating of perceived exertion (RPE) were measured during exercise and capillary glucose concentrations were measured for 2 h postprandial. Following exercise, appetite perceptions were assessed and Lumen expired carbon dioxide percentage (L%CO2) was measured as an index of fat oxidation. Heart rate (85 ± 5%) and RPE (14 ± 2) did not differ between conditions (p > 0.05). Postprandial glucose mean (6.1 ± 0.6 vs. 6.8 ± 0.8 mmol/L, p = 0.03), peak (7.4 ± 1.2 vs. 8.5 ± 1.5 mmol/L, p = 0.01), and area under the curve (AUC) (758 ± 72 vs. 973 ± 82 mmol/L × 2 h, p = 0.004) were lower in FedEX versus FastEX. Appetite perceptions were lower in FedEX versus FastEX (-87.63 ± 58.51 vs. -42.06 ± 34.96 mm, p = 0.029). Post-exercise L%CO2 was transiently decreased 30 min post-exercise in both conditions (4.03 ± 0.38 vs. 4.29 ± 0.34%, p = 0.0023), reflective of increased fat oxidation following BWE. These findings demonstrate that BWE performed in the fed compared to the fasted state lowered postprandial glycemia and appetite perceptions in females.
关于在实验室外进行的体重间歇运动(BWE)对新陈代谢健康益处的研究十分有限。运动后的代谢反应也会受到运动前后进餐时间的影响,但体重间歇运动与营养的交互作用尚不清楚。本研究调查了在空腹或进食状态下进行负重运动对餐后血糖、运动后脂肪氧化和食欲感知的影响。12名女性(23±2岁;22±2kg/m2)接受了两项虚拟监测试验,包括在标准早餐前5分钟(FastEX)或早餐后10分钟(FedEX)完成体力锻炼(10x1分钟,1分钟恢复)或开始体力锻炼。在运动过程中测量心率和体力消耗等级(RPE),并在餐后 2 小时测量毛细血管葡萄糖浓度。运动后,对食欲进行评估,并测量腔呼出二氧化碳百分比(L%CO2)作为脂肪氧化指数。心率(85±5%)和 RPE(14±2)在不同条件下没有差异(P>0.05)。餐后血糖平均值(6.1±0.6 vs. 6.8±0.8 mmol/L,p=0.03)、峰值(7.4±1.2 vs. 8.5±1.5 mmol/L,p=0.01)和曲线下面积(AUC)(758±72 vs. 973±82 mmol/L x 2 hr,p=0.004)均低于 FedEX 和 FastEX。FedEX与FastEX相比,食欲感知较低(-87.63±58.51 vs. -42.06 ± 34.96 mm,p=0.029)。两种情况下,运动后 L%CO2 在运动后 30 分钟内均出现短暂下降(4.03±0.38 vs. 4.29±0.34%,p=0.0023),反映出 BWE 后脂肪氧化增加。这些研究结果表明,与空腹状态相比,在进食状态下进行的裸腹运动可降低女性的餐后血糖和食欲感知。ClinicalTrials.gov (NCT06240442)。
{"title":"At-home bodyweight interval exercise in the fed versus fasted state lowers postprandial glycemia and appetite perceptions in females.","authors":"Alexa Govette, Jenna B Gillen","doi":"10.1139/apnm-2023-0485","DOIUrl":"10.1139/apnm-2023-0485","url":null,"abstract":"<p><p>Limited research has characterized the metabolic health benefits of bodyweight interval exercise (BWE) performed outside of a laboratory setting. Metabolic responses to exercise can also be influenced by meal timing around exercise, but the interactive effects of BWE and nutrition are unknown. This study investigated the effects of BWE performed in the fasted or fed state on postprandial glycemia, post-exercise fat oxidation and appetite perceptions. Twelve females (23 ± 2 years; 22 ± 2 kg/m<sup>2</sup>) underwent two virtually-monitored trials that involved completing BWE (10 × 1 min, 1 min recovery) 5 min before (FastEX) or beginning BWE 10 min after (FedEX) a standardized breakfast. Heart rate and rating of perceived exertion (RPE) were measured during exercise and capillary glucose concentrations were measured for 2 h postprandial. Following exercise, appetite perceptions were assessed and Lumen expired carbon dioxide percentage (L%CO<sub>2</sub>) was measured as an index of fat oxidation. Heart rate (85 ± 5%) and RPE (14 ± 2) did not differ between conditions (<i>p</i> > 0.05). Postprandial glucose mean (6.1 ± 0.6 vs. 6.8 ± 0.8 mmol/L, <i>p</i> = 0.03), peak (7.4 ± 1.2 vs. 8.5 ± 1.5 mmol/L, <i>p</i> = 0.01), and area under the curve (AUC) (758 ± 72 vs. 973 ± 82 mmol/L × 2 h, <i>p</i> = 0.004) were lower in FedEX versus FastEX. Appetite perceptions were lower in FedEX versus FastEX (-87.63 ± 58.51 vs. -42.06 ± 34.96 mm, <i>p</i> = 0.029). Post-exercise L%CO<sub>2</sub> was transiently decreased 30 min post-exercise in both conditions (4.03 ± 0.38 vs. 4.29 ± 0.34%, <i>p</i> = 0.0023), reflective of increased fat oxidation following BWE. These findings demonstrate that BWE performed in the fed compared to the fasted state lowered postprandial glycemia and appetite perceptions in females.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141082717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-07-16DOI: 10.1139/apnm-2023-0573
David S Wishart
This report describes the knowledge mobilization and translation outcomes of the Canadian-funded portion of a large, international project called the Food Biomarker Alliance (FoodBAll), which ran from 2015 to 2019. This remarkably successful project led to a large number of important findings, outputs, and impacts. In particular, FoodBAll unequivocally demonstrated that metabolomics could be used to not only discover biomarkers of food intake (BFIs), but also to measure diet in a more objective manner. FoodBAll also created standards for assessing and validating BFIs, papers and databases describing BFIs, and kits for measuring BFIs and it laid the groundwork for many global studies exploring food composition and precision nutrition.
{"title":"Knowledge translation and knowledge mobilization from the FoodBAll project.","authors":"David S Wishart","doi":"10.1139/apnm-2023-0573","DOIUrl":"10.1139/apnm-2023-0573","url":null,"abstract":"<p><p>This report describes the knowledge mobilization and translation outcomes of the Canadian-funded portion of a large, international project called the Food Biomarker Alliance (FoodBAll), which ran from 2015 to 2019. This remarkably successful project led to a large number of important findings, outputs, and impacts. In particular, FoodBAll unequivocally demonstrated that metabolomics could be used to not only discover biomarkers of food intake (BFIs), but also to measure diet in a more objective manner. FoodBAll also created standards for assessing and validating BFIs, papers and databases describing BFIs, and kits for measuring BFIs and it laid the groundwork for many global studies exploring food composition and precision nutrition.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141621945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-05-07DOI: 10.1139/apnm-2023-0230
Diego Augusto Santos Silva, Markus Joseph Duncan, Nicholas Kuzik, Mark S Tremblay
Early menarche has been associated with adverse health outcomes, such as depressive symptoms. Discovering effect modifiers across these conditions in the pediatric population is a constant challenge. We tested whether movement behaviours modified the effect of the association between early menarche and depression symptoms among adolescents. This cross-sectional study included 2031 females aged 15-19 years across all Brazilian geographic regions. Data were collected using a self-administered questionnaire; 30.5% (n = 620) reported having experienced menarche before age 12 years (i.e., early menarche). We used the Patient Health Questionnaire (PHQ-9) to evaluate depressive symptoms. Accruing any moderate-vigorous physical activity during leisure time, limited recreational screen time, and having good sleep quality were the exposures investigated. Adolescents who experienced early menarche and met one (B: -4.45, 95% CI: (-5.38, -3.51)), two (B: -6.07 (-7.02, -5.12)), or three (B: -6.49 (-7.76, -5.21)), and adolescents who experienced not early menarche and met one (B: -5.33 (-6.20; -4.46)), two (B: -6.12 (-6.99; -5.24)), or three (B: -6.27 (-7.30; -5.24)) of the movement behaviour targets had lower PHQ-9 scores for depression symptoms than adolescents who experienced early menarche and did not meet any of the movement behaviours. The disparities in depressive symptoms among the adolescents (early menarche vs. not early menarche) who adhered to all three target behaviours were not statistically significant (B: 0.41 (-0.19; 1.01)). Adherence to movement behaviours modified the effect of the association between early menarche and depression symptoms.
{"title":"Do movement behaviours influence the association between early menarche and depression symptoms among Brazilian adolescents?","authors":"Diego Augusto Santos Silva, Markus Joseph Duncan, Nicholas Kuzik, Mark S Tremblay","doi":"10.1139/apnm-2023-0230","DOIUrl":"10.1139/apnm-2023-0230","url":null,"abstract":"<p><p>Early menarche has been associated with adverse health outcomes, such as depressive symptoms. Discovering effect modifiers across these conditions in the pediatric population is a constant challenge. We tested whether movement behaviours modified the effect of the association between early menarche and depression symptoms among adolescents. This cross-sectional study included 2031 females aged 15-19 years across all Brazilian geographic regions. Data were collected using a self-administered questionnaire; 30.5% (<i>n</i> = 620) reported having experienced menarche before age 12 years (i.e., early menarche). We used the Patient Health Questionnaire (PHQ-9) to evaluate depressive symptoms. Accruing any moderate-vigorous physical activity during leisure time, limited recreational screen time, and having good sleep quality were the exposures investigated. Adolescents who experienced early menarche and met one (<i>B</i>: -4.45, 95% CI: (-5.38, -3.51)), two (<i>B</i>: -6.07 (-7.02, -5.12)), or three (<i>B</i>: -6.49 (-7.76, -5.21)), and adolescents who experienced not early menarche and met one (<i>B</i>: -5.33 (-6.20; -4.46)), two (<i>B</i>: -6.12 (-6.99; -5.24)), or three (<i>B</i>: -6.27 (-7.30; -5.24)) of the movement behaviour targets had lower PHQ-9 scores for depression symptoms than adolescents who experienced early menarche and did not meet any of the movement behaviours. The disparities in depressive symptoms among the adolescents (early menarche vs. not early menarche) who adhered to all three target behaviours were not statistically significant (<i>B:</i> 0.41 (-0.19; 1.01)). Adherence to movement behaviours modified the effect of the association between early menarche and depression symptoms.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140878147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-05-10DOI: 10.1139/apnm-2024-0063
Siya Khanna, Susanne Aufreiter, Amanda J MacFarlane, Yaseer A Shakur, Deborah L O'Connor
In 1998, Health Canada mandated folic acid fortification of white flour and enriched grain products to prevent neural tube defects. At the time, neither the Canadian Nutrient File (CNF) nor product labels reflected the actual folate content of foods. We aimed to assess if 20 years post-fortification, the CNF values for total folate and synthetic folic acid accurately reflect amounts determined by direct analysis. Using the 2001 Food Expenditure Survey and ACNielsen Company data, we identified 10-15 of the most purchased fortified foods across seven food categories in Canada. Total folate concentrations were determined by tri-enzyme digestion and microbial assay. Folic acid concentrations were determined using liquid chromatography-tandem mass spectrometry. Except for "cooked pastas", mean total folate content of foods (n = 89) were significantly higher than CNF values across categories (p < 0.05), reflecting 167% ± 54% of CNF values. Similarly, mean folic acid content of foods was higher than CNF values for all categories except "cooked pastas" (p < 0.05), with a mean of 188% ± 94% of CNF values; the latter CNF values included uncooked pasta. In sum, 20 years post-fortification, and 10 years since the last direct measurement, CNF and product label values still underestimate actual total folate and the folic acid content of foods. These findings emphasize that dietary estimates established using the CNF may significantly underestimate actual intakes and thus caution should be exercised when interpreting estimates of nutritional adequacy based on these values.
{"title":"Folate and synthetic folic acid content in Canadian fortified foods two decades after mandatory fortification.","authors":"Siya Khanna, Susanne Aufreiter, Amanda J MacFarlane, Yaseer A Shakur, Deborah L O'Connor","doi":"10.1139/apnm-2024-0063","DOIUrl":"10.1139/apnm-2024-0063","url":null,"abstract":"<p><p>In 1998, Health Canada mandated folic acid fortification of white flour and enriched grain products to prevent neural tube defects. At the time, neither the Canadian Nutrient File (CNF) nor product labels reflected the actual folate content of foods. We aimed to assess if 20 years post-fortification, the CNF values for total folate and synthetic folic acid accurately reflect amounts determined by direct analysis. Using the 2001 Food Expenditure Survey and ACNielsen Company data, we identified 10-15 of the most purchased fortified foods across seven food categories in Canada. Total folate concentrations were determined by tri-enzyme digestion and microbial assay. Folic acid concentrations were determined using liquid chromatography-tandem mass spectrometry. Except for \"cooked pastas\", mean total folate content of foods (<i>n</i> = 89) were significantly higher than CNF values across categories (<i>p</i> < 0.05), reflecting 167% ± 54% of CNF values. Similarly, mean folic acid content of foods was higher than CNF values for all categories except \"cooked pastas\" (<i>p</i> < 0.05), with a mean of 188% ± 94% of CNF values; the latter CNF values included uncooked pasta. In sum, 20 years post-fortification, and 10 years since the last direct measurement, CNF and product label values still underestimate actual total folate and the folic acid content of foods. These findings emphasize that dietary estimates established using the CNF may significantly underestimate actual intakes and thus caution should be exercised when interpreting estimates of nutritional adequacy based on these values.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140904309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-06-03DOI: 10.1139/apnm-2024-0135
Robert D Meade, Ashley P Akerman, Sean R Notley, Nathalie V Kirby, Ronald J Sigal, Glen P Kenny
Older adults are at elevated risk of heat-related mortality due to age-associated declines in thermoregulatory and cardiovascular function. However, the inter-individual factors that exacerbate physiological heat strain during heat exposure remain unclear, making it challenging to identify more heat-vulnerable subgroups. We therefore explored factors contributing to inter-individual variability in physiological responses of older adults exposed to simulated hot weather. Thirty-seven older adults (61-80 years, 16 females) rested for 8 h in 31 and 36 °C (45% relative humidity). Core (rectal) temperature, heart rate (HR), HR variability, mean arterial pressure (MAP), and cardiac autonomic responses to standing were measured at baseline and end-exposure. Bootstrapped least absolute shrinkage and selection operator regression was used to evaluate whether variation in these responses was related to type 2 diabetes (T2D, n = 10), hypertension (n = 18), age, sex, body morphology, habitual physical activity levels, and/or heat-acclimatization. T2D was identified as a predictor of end-exposure HR (with vs. without: 13 beats/min (bootstrap 95% confidence interval: 6, 23)), seated MAP (-7 mmHg (-18, 1)), and the systolic pressure response to standing (20 mmHg (4, 36)). HR was also influenced by sex (female vs. male: 8 beats/min (1, 16)). No other predictors were identified. The inter-individual factors explored did not meaningfully contribute to the variation in body temperature responses in older adults exposed to simulated indoor overheating. By contrast, cardiovascular responses were exacerbated in females and individuals with T2D. These findings improve understanding of how inter-individual differences contribute to heat-induced physiological strain in older persons.
{"title":"Exploring the contribution of inter-individual factors to the development of physiological heat strain in older adults exposed to simulated indoor overheating.","authors":"Robert D Meade, Ashley P Akerman, Sean R Notley, Nathalie V Kirby, Ronald J Sigal, Glen P Kenny","doi":"10.1139/apnm-2024-0135","DOIUrl":"10.1139/apnm-2024-0135","url":null,"abstract":"<p><p>Older adults are at elevated risk of heat-related mortality due to age-associated declines in thermoregulatory and cardiovascular function. However, the inter-individual factors that exacerbate physiological heat strain during heat exposure remain unclear, making it challenging to identify more heat-vulnerable subgroups. We therefore explored factors contributing to inter-individual variability in physiological responses of older adults exposed to simulated hot weather. Thirty-seven older adults (61-80 years, 16 females) rested for 8 h in 31 and 36 °C (45% relative humidity). Core (rectal) temperature, heart rate (HR), HR variability, mean arterial pressure (MAP), and cardiac autonomic responses to standing were measured at baseline and end-exposure. Bootstrapped least absolute shrinkage and selection operator regression was used to evaluate whether variation in these responses was related to type 2 diabetes (T2D, <i>n</i> = 10), hypertension (<i>n</i> = 18), age, sex, body morphology, habitual physical activity levels, and/or heat-acclimatization. T2D was identified as a predictor of end-exposure HR (with vs. without: 13 beats/min (bootstrap 95% confidence interval: 6, 23)), seated MAP (-7 mmHg (-18, 1)), and the systolic pressure response to standing (20 mmHg (4, 36)). HR was also influenced by sex (female vs. male: 8 beats/min (1, 16)). No other predictors were identified. The inter-individual factors explored did not meaningfully contribute to the variation in body temperature responses in older adults exposed to simulated indoor overheating. By contrast, cardiovascular responses were exacerbated in females and individuals with T2D. These findings improve understanding of how inter-individual differences contribute to heat-induced physiological strain in older persons.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141238912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-05-21DOI: 10.1139/apnm-2024-0094
Ben J Lee, Sophie L Russell, Robert D Meade, James J McCormick, Kelli E King, Glen P Kenny
Heat stress induced damage to the gastrointestinal barrier can induce local and systemic inflammatory reactions implicated in heat-stroke. Gastrointestinal barrier damage has been shown to be greater in older relative to young adults following hyperthermia. However, comparisons between young and older adults have been limited to brief exposures (3 h), which may not reflect the duration of heat stress experienced during heat waves. We therefore evaluated markers of intestinal epithelial damage (log transformed intestinal fatty acid binding protein, IFABPLOG), microbial translocation (soluble cluster of differentiation 14, sCD14LOG), and systemic inflammation (tumour necrosis factor alpha, TNF-αLOG; interleukin 6, IL-6LOG; C-reactive protein, CRP) in 19 young (interquartile range: 21-27 years; 10 females) and 37 older (68-73 years; 10 females) adults before and after 9 h of rest in 40 °C (9% relative humidity). The magnitude of the increase in IFABPLOG was 0.38 log pg/mL (95% CI, 0.10, 0.65 log pg/mL) greater in the older relative to young cohort (P = 0.049) after 9 h heat exposure. At baseline both IL-6LOG and CRP concentrations were higher in the older (IL-6: 2.67 (1.5) log pg/mL, CRP: 0.28 (1.5) mg/mL) relative to the young (IL-6: 1.59 log pg/mL, SD 1.2; CRP: 0.11 mg/mL, SD 1.7) group (both P ≤ 0.001). The change in IL-6 and CRP was similar between groups following 9 h heat exposure (IL-6: P = 0.053; CRP: P = 0.241). Neither sCD14LOG and TNF-αLOG were different between groups at baseline nor altered after 9 h heat exposure. Our data indicate that age may modify intestinal epithelial injury following 9 h of passive heat exposure.
{"title":"Markers of enterocyte damage, microbial translocation, and systemic inflammation following 9 h of heat exposure in young and older adults.","authors":"Ben J Lee, Sophie L Russell, Robert D Meade, James J McCormick, Kelli E King, Glen P Kenny","doi":"10.1139/apnm-2024-0094","DOIUrl":"10.1139/apnm-2024-0094","url":null,"abstract":"<p><p>Heat stress induced damage to the gastrointestinal barrier can induce local and systemic inflammatory reactions implicated in heat-stroke. Gastrointestinal barrier damage has been shown to be greater in older relative to young adults following hyperthermia. However, comparisons between young and older adults have been limited to brief exposures (3 h), which may not reflect the duration of heat stress experienced during heat waves. We therefore evaluated markers of intestinal epithelial damage (log transformed intestinal fatty acid binding protein, IFABP<sub>LOG</sub>), microbial translocation (soluble cluster of differentiation 14, sCD14<sub>LOG</sub>), and systemic inflammation (tumour necrosis factor alpha, TNF-α<sub>LOG</sub>; interleukin 6, IL-6<sub>LOG</sub>; C-reactive protein, CRP) in 19 young (interquartile range: 21-27 years; 10 females) and 37 older (68-73 years; 10 females) adults before and after 9 h of rest in 40 °C (9% relative humidity). The magnitude of the increase in IFABP<sub>LOG</sub> was 0.38 log pg/mL (95% CI, 0.10, 0.65 log pg/mL) greater in the older relative to young cohort (<i>P</i> = 0.049) after 9 h heat exposure. At baseline both IL-6<sub>LOG</sub> and CRP concentrations were higher in the older (IL-6: 2.67 (1.5) log pg/mL, CRP: 0.28 (1.5) mg/mL) relative to the young (IL-6: 1.59 log pg/mL, SD 1.2; CRP: 0.11 mg/mL, SD 1.7) group (both <i>P</i> ≤ 0.001). The change in IL-6 and CRP was similar between groups following 9 h heat exposure (IL-6: <i>P</i> = 0.053; CRP: <i>P</i> = 0.241). Neither sCD14<sub>LOG</sub> and TNF-α<sub>LOG</sub> were different between groups at baseline nor altered after 9 h heat exposure. Our data indicate that age may modify intestinal epithelial injury following 9 h of passive heat exposure.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141077413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Although evidence suggests that intramuscular fat infiltration may influence muscle strength, the precise mechanisms remain unclear. This study aimed to determine whether intramuscular fat infiltration affects muscle mechanical properties during contraction and whether these mechanical properties mediate the relationship between intramuscular fat infiltration and muscle strength. Seventy-nine healthy older women aged 75.1 ± 6.8 years were included in this study. The echo intensity (EI) of the vastus lateralis (VL) was measured as an intramuscular fat infiltration index using B-mode ultrasonography. Maximum voluntary isometric contraction strength (MVIC) was assessed using a dynamometer. The VL shear elastic modulus (G), a mechanical property index, was measured using ultrasound shear wave elastography under various muscle contraction conditions, at rest and at 15%, 30%, and 45% MVIC (G0, G15, G30, and G45). To evaluate the degree of increase in the shear elastic modulus with increasing muscle contraction intensity, the slope of the regression line (Gslope) between muscle contraction and shear elastic modulus was calculated for each participant. The results showed that EI was significantly associated with G30 and G45 but not with G0 or G15. The EI can significantly explain the inter-individual differences in Gslope. Mediation analysis revealed that the effect of EI on MVIC through Gslope was significant (indirect effect = -0.31, 95% confidence interval (-0.57, -0.12)). These findings suggest that a greater EI is associated with a lower G during muscle contraction. Furthermore, our results show that the relationship between EI and MVIC is mediated by Gslope.
{"title":"Intramuscular fat infiltration influences mechanical properties during muscle contraction in older women.","authors":"Zimin Wang, Masashi Taniguchi, Junya Saeki, Masahide Yagi, Norihiko Murota, Kaede Nakazato, Nanami Niiya, Noriaki Ichihashi","doi":"10.1139/apnm-2023-0557","DOIUrl":"10.1139/apnm-2023-0557","url":null,"abstract":"<p><p>Although evidence suggests that intramuscular fat infiltration may influence muscle strength, the precise mechanisms remain unclear. This study aimed to determine whether intramuscular fat infiltration affects muscle mechanical properties during contraction and whether these mechanical properties mediate the relationship between intramuscular fat infiltration and muscle strength. Seventy-nine healthy older women aged 75.1 ± 6.8 years were included in this study. The echo intensity (EI) of the vastus lateralis (VL) was measured as an intramuscular fat infiltration index using B-mode ultrasonography. Maximum voluntary isometric contraction strength (MVIC) was assessed using a dynamometer. The VL shear elastic modulus (G), a mechanical property index, was measured using ultrasound shear wave elastography under various muscle contraction conditions, at rest and at 15%, 30%, and 45% MVIC (G0, G15, G30, and G45). To evaluate the degree of increase in the shear elastic modulus with increasing muscle contraction intensity, the slope of the regression line (Gslope) between muscle contraction and shear elastic modulus was calculated for each participant. The results showed that EI was significantly associated with G30 and G45 but not with G0 or G15. The EI can significantly explain the inter-individual differences in Gslope. Mediation analysis revealed that the effect of EI on MVIC through Gslope was significant (indirect effect = -0.31, 95% confidence interval (-0.57, -0.12)). These findings suggest that a greater EI is associated with a lower G during muscle contraction. Furthermore, our results show that the relationship between EI and MVIC is mediated by Gslope.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140892278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-05-22DOI: 10.1139/apnm-2023-0447
Alicia M Kells, M Erin Moir, Geoff B Coombs, Andrew W D'Souza, Stephen A Klassen, Baraa K Al-Khazraji, J Kevin Shoemaker
The aim of this study was to determine the effect of posture changes on vascular compliance in intracranial (brain) versus extracranial vascular beds (forearm). Eighteen young adults (nine females) performed a supine-to-seated-to-standing protocol involving 5 min of rest in each position. Continuous blood pressure, middle cerebral artery (MCA) blood velocity, and brachial artery blood velocity were recorded at each posture. Three to five consecutive steady-state cardiac cycles at each posture were analyzed by a four-element lumped parameter modified Windkessel model to calculate vascular compliance. Mean arterial pressure (MAP) increased from supine to seated (76(9) vs. 81(12) mmHg; P = 0.006) and from supine to standing (76(9) vs. 82(13) mmHg; P = 0.034). Mean blood flow was greater in the MCA relative to the forearm (forearm: 40(5) mL·min-1, MCA: 224(17) mL·min-1; main effect P < 0.001). Conversely, vascular resistance (forearm: 3.25(0.50) mmHg-1·mL·min-1, brain: 0.36(0.04) mmHg-1·mL·min-1; main effect P < 0.001) and compliance (forearm: 0.010(0.001) mL·min-1·mmHg-1, brain: 0.005(0.001) mL·min-1·mmHg-1; main effect P = 0.001) were greater in the forearm compared to the brain. Significant main effects of posture were observed with decreasing values in upright positions for mean blood flow (P = 0.001) in both vascular beds, but not for resistance (P = 0.163) or compliance (P = 0.385). There were no significant interaction effects between vascular bed and posture for mean flow (P = 0.057), resistance (P = 0.258), or compliance (P = 0.329). This study provides evidence that under steady-state conditions, posture does not affect cerebrovascular compliance.
本研究旨在确定姿势变化对颅内(脑部)与颅外血管床(前臂)血管顺应性的影响。18 名年轻人(9 名女性)进行了从仰卧到坐立再到站立的训练,每个姿势休息 5 分钟。在每个姿势下连续记录血压、大脑中动脉(MCA)血流速度和肱动脉血流速度。在每个姿势下连续进行三到五个稳态心脏循环,通过四要素凑合参数修正 Windkessel 模型进行分析,以计算血管顺应性。从仰卧到坐位(76[9] vs 81[12] mmHg;P=0.006)以及从仰卧到站立(76[9] vs 82[13] mmHg;P=0.034),平均动脉压(MAP)均有所增加。相对于前臂,MCA 的平均血流量更大(前臂:40[5] ml-min-1,MCA:224[17] ml-min-1;主效应 P=0.006)。
{"title":"No influence of steady-state postural changes on cerebrovascular compliance in humans.","authors":"Alicia M Kells, M Erin Moir, Geoff B Coombs, Andrew W D'Souza, Stephen A Klassen, Baraa K Al-Khazraji, J Kevin Shoemaker","doi":"10.1139/apnm-2023-0447","DOIUrl":"10.1139/apnm-2023-0447","url":null,"abstract":"<p><p>The aim of this study was to determine the effect of posture changes on vascular compliance in intracranial (brain) versus extracranial vascular beds (forearm). Eighteen young adults (nine females) performed a supine-to-seated-to-standing protocol involving 5 min of rest in each position. Continuous blood pressure, middle cerebral artery (MCA) blood velocity, and brachial artery blood velocity were recorded at each posture. Three to five consecutive steady-state cardiac cycles at each posture were analyzed by a four-element lumped parameter modified Windkessel model to calculate vascular compliance. Mean arterial pressure (MAP) increased from supine to seated (76(9) vs. 81(12) mmHg; <i>P</i> = 0.006) and from supine to standing (76(9) vs. 82(13) mmHg; <i>P</i> = 0.034). Mean blood flow was greater in the MCA relative to the forearm (forearm: 40(5) mL·min<sup>-1</sup>, MCA: 224(17) mL·min<sup>-1</sup>; main effect <i>P</i> < 0.001). Conversely, vascular resistance (forearm: 3.25(0.50) mmHg<sup>-1</sup>·mL·min<sup>-1</sup>, brain: 0.36(0.04) mmHg<sup>-1</sup>·mL·min<sup>-1</sup>; main effect <i>P</i> < 0.001) and compliance (forearm: 0.010(0.001) mL·min<sup>-1</sup>·mmHg<sup>-1</sup>, brain: 0.005(0.001) mL·min<sup>-1</sup>·mmHg<sup>-1</sup>; main effect <i>P</i> = 0.001) were greater in the forearm compared to the brain. Significant main effects of posture were observed with decreasing values in upright positions for mean blood flow (<i>P</i> = 0.001) in both vascular beds, but not for resistance (<i>P</i> = 0.163) or compliance (<i>P</i> = 0.385). There were no significant interaction effects between vascular bed and posture for mean flow (<i>P</i> = 0.057), resistance (<i>P</i> = 0.258), or compliance (<i>P</i> = 0.329). This study provides evidence that under steady-state conditions, posture does not affect cerebrovascular compliance.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141082818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-05-07DOI: 10.1139/apnm-2024-0037
Alexiaa Sim, Hui Qing Tan, Yusuf Ali, Stephen F Burns
This study investigated the effect of 4 days low energy availability (LEA) on physiological markers and mood states in male endurance runners. Twelve participants (mean (standard deviation); age: 25.8 (3.8) years; fat-free mass (FFM): 52.8 (5.5) kg) completed three 4-day conditions: adequate energy availability (AEA): 45 kcal/kg FFM/day; LEA1: 30 kcal/kg FFM/day; and LEA2: 15 kcal/kg FFM/day, in a randomized order. Participants ran on a treadmill at 65% of V̇O2max until they expended 15 kcal/kg FFM/day of energy. Energy intake was adjusted to achieve the desired energy availability. Pre- and post-measurements of bone turnover, metabolism, testosterone and estradiol (plasma), resting metabolic rate (indirect calorimetry), and mood states (Brunel Mood Scale) were assessed. The results reported a significant decrease in testosterone (condition × time interaction, p = 0.03) occurred on LEA2 (Pre: 23.8 (7.0) nmol/L vs. Post: 20.3 (7.7) nmol/L) compared with AEA (Pre: 22.9 (5.5) nmol/L vs. Post: 23.3 (6.1) nmol/L) or LEA1 (Pre: 23.6 (8.6) nmol/L vs. Post: 20.9 (8.8) nmol/L). Fatigue level significantly increased (condition × time interaction, p = 0.02) in LEA2 (Pre: 3.5 (1.7) vs. Post: 6.5 (2.9)) but did not change in AEA (Pre: 2.8 (1.5) vs. Post: 2.5 (2.7)) or LEA1 (Pre: 2.8(2.4) vs. Post: 2.9 (2.0)). Other measures were unaffected by the interventions. In conclusion, this study suggests that testosterone and fatigue may serve as early indicators of LEA in male runners. However, other physiological markers and mood states appeared largely unaffected, aligning with existing literature indicating minimal disruption of physiological functions during acute LEA in male athletes. Study registration: Australian New Zealand Clinical Trials Registry (Trial No.: 381278).
本研究调查了四天低能量可用性(LEA)对男性耐力跑运动员生理指标和情绪状态的影响。12 名参与者(平均值(标准差);年龄:25.8(3.8)岁;无脂肪重量(FFM):52.8(5.5)千克)完成了三个为期 4 天的条件:参与者按随机顺序完成三个为期 4 天的条件:充足能量供应(AEA:45 千卡/千克FFM/天;LEA1:30 千卡/千克FFM/天;LEA2:15 千卡/千克FFM/天)。参与者在跑步机上以 65% 的 V̇O2max 速度跑步,直到消耗掉 15 千卡/千克 FFM/天的能量。能量摄入量经过调整,以达到预期的 EA。对骨质流失、新陈代谢、睾酮和雌二醇(血浆)、静息代谢率(间接热量测定法)和情绪状态(布鲁内尔情绪量表)进行了前后测量。结果表明,LEA2 的睾酮明显下降(条件 × 时间交互作用,p=0.03)(前:23.8 (7.0) nmol/L vs 后:20.3 (7.7) nmol/L vs 前:20.8 (7.0) nmol/L vs 后:20.3 (7.7) nmol/L):20.3 (7.7) nmol/L)与 AEA(前:22.9 (5.5) nmol/L vs 后:23.3 (6.1) nmol/L)相比:23.3 (6.1) nmol/L)或 LEA1(前:23.6 (8.6) nmol/L vs 后:20.9 (8.8) nmol/L)相比:20.9 (8.8) nmol/L)。疲劳程度在 LEA2(前:3.5 (1.7) vs 后:6.5 (2.9) )中明显增加(条件 × 时间交互作用,p=0.02):6.5 (2.9)),但 AEA(前:2.8 (1.5) vs 后:2.5 (2.7) )没有变化:2.5 (2.7))或 LEA1(前:2.8(2.4) vs 后:2.9 (2.0)2.9 (2.0)).其他指标不受干预措施的影响。总之,这项研究表明,睾酮和疲劳可作为男性跑步者 LEA 的早期指标。然而,其他生理指标和情绪状态似乎基本未受影响,这与现有文献表明男性运动员在急性 LEA 期间生理功能受到最小干扰的观点一致。
{"title":"Original investigation: manipulating energy availability in male endurance runners: a randomised controlled trial.","authors":"Alexiaa Sim, Hui Qing Tan, Yusuf Ali, Stephen F Burns","doi":"10.1139/apnm-2024-0037","DOIUrl":"10.1139/apnm-2024-0037","url":null,"abstract":"<p><p>This study investigated the effect of 4 days low energy availability (LEA) on physiological markers and mood states in male endurance runners. Twelve participants (mean (standard deviation); age: 25.8 (3.8) years; fat-free mass (FFM): 52.8 (5.5) kg) completed three 4-day conditions: adequate energy availability (AEA): 45 kcal/kg FFM/day; LEA1: 30 kcal/kg FFM/day; and LEA2: 15 kcal/kg FFM/day, in a randomized order. Participants ran on a treadmill at 65% of V̇O<sub>2</sub>max until they expended 15 kcal/kg FFM/day of energy. Energy intake was adjusted to achieve the desired energy availability. Pre- and post-measurements of bone turnover, metabolism, testosterone and estradiol (plasma), resting metabolic rate (indirect calorimetry), and mood states (Brunel Mood Scale) were assessed. The results reported a significant decrease in testosterone (condition × time interaction, <i>p</i> = 0.03) occurred on LEA2 (Pre: 23.8 (7.0) nmol/L vs. Post: 20.3 (7.7) nmol/L) compared with AEA (Pre: 22.9 (5.5) nmol/L vs. Post: 23.3 (6.1) nmol/L) or LEA1 (Pre: 23.6 (8.6) nmol/L vs. Post: 20.9 (8.8) nmol/L). Fatigue level significantly increased (condition × time interaction, <i>p</i> = 0.02) in LEA2 (Pre: 3.5 (1.7) vs. Post: 6.5 (2.9)) but did not change in AEA (Pre: 2.8 (1.5) vs. Post: 2.5 (2.7)) or LEA1 (Pre: 2.8(2.4) vs. Post: 2.9 (2.0)). Other measures were unaffected by the interventions. In conclusion, this study suggests that testosterone and fatigue may serve as early indicators of LEA in male runners. However, other physiological markers and mood states appeared largely unaffected, aligning with existing literature indicating minimal disruption of physiological functions during acute LEA in male athletes. Study registration: Australian New Zealand Clinical Trials Registry (Trial No.: 381278).</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140878148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-07-12DOI: 10.1139/apnm-2023-0606
Alyssa M Fenuta, Patrick J Drouin, Zach I N Kohoko, Mytchel J T Lynn, Michael E Tschakovsky
Beetroot juice supplementation (BRJ) should increase nitric oxide bioavailability under conditions of muscle deoxygenation and acidosis that are a normal consequence of the maximal effort exercise test used to identify forearm critical impulse. We hypothesized BRJ would improve oxygen delivery:demand matching and forearm critical impulse performance. Healthy males (20.8 ± 2.4 years) participated in a randomized crossover trial between October 2017 and May 2018 (Queen's University, Kingston, ON). Participants completed 10 min of rhythmic maximal effort forearm handgrip exercise 2.5 h post placebo (PL) vs. BRJ (9 completed PL/BRJ vs. 4 completed BRJ/PL) within a 2 week period. Data are presented as mean ± SD. There was a main effect of drink (PL > BRJ) for oxygen extraction (P = 0.033, ηp2 = 0.351) and oxygen consumption/force (P = 0.017, ηp2 = 0.417). There was a drink × time interaction (PL > BRJ) for oxygen consumption/force (P = 0.035, ηp2 = 0.216) between 75 and 360 s (1.25-6 min) from exercise onset. BRJ did not influence oxygen delivery (P = 0.953, ηp2 = 0.000), oxygen consumption (P = 0.064, ηp2 = 0.278), metabolites ((lactate) (P = 0.196, ηp2 = 0.135), pH (P = 0.759, ηp2 = 0.008)) or power-duration performance parameters (critical impulse (P = 0.379, d = 0.253), W' (P = 0.733, d = 0.097)). BRJ during all-out handgrip exercise does not influence oxygen delivery or exercise performance. Oxygen cost of contraction with BRJ is reduced as contraction impulse is declining during maximal effort exercise resulting in less oxygen extraction.
补充甜菜根汁(BRJ)可提高缺氧和酸中毒条件下的一氧化氮生物利用率,这是最大努力运动的特征,也是识别前臂临界冲力所必需的。我们假设一氧化氮补充剂将改善氧气输送:需求匹配和前臂临界冲力表现。2017年10月至2018年5月期间,健康男性(20.8±2.4岁)参加了一项随机交叉试验(安大略省金斯顿皇后大学)。参与者在安慰剂(PL)与BRJ(9人完成PL/BRJ vs. 4人完成BRJ/PL)后2.5小时内完成10分钟的有节奏的最大努力前臂手握运动,为期2周。数据以平均值±SD表示。饮料(PL > BRJ)对氧气提取量(P=0.033,ηp2=0.351)和氧气消耗量/力量(P=0.017,ηp2=0.417)有主效应。在运动开始 75-360 秒(1.25-6 分钟)之间,耗氧量/力量(P=0.035,ηp2=0.216)与饮料 x 时间存在交互作用(PL > BRJ)。BRJ 不影响氧输送量(P=0.953,ηp2=0.000)、耗氧量(P=0.064,ηp2=0.278)、代谢物[[乳酸盐](P=0.196,ηp2=0.135)、pH 值(P=0.759,ηp2=0.008)]或功率-持续时间性能参数[临界冲量(P=0.379,d=0.253)、W'(P=0.733,d=0.097)]。全力握手运动中的 BRJ 不会影响氧气输送或运动表现。在最大努力运动时,由于收缩冲量下降,BRJ 收缩的氧气成本降低,导致氧气汲取量减少。https://osf.io/pga37/registrations。
{"title":"Influence of acute dietary nitrate supplementation on oxygen delivery/consumption and critical impulse during maximal effort forearm exercise in males: a randomized crossover trial.","authors":"Alyssa M Fenuta, Patrick J Drouin, Zach I N Kohoko, Mytchel J T Lynn, Michael E Tschakovsky","doi":"10.1139/apnm-2023-0606","DOIUrl":"10.1139/apnm-2023-0606","url":null,"abstract":"<p><p>Beetroot juice supplementation (BRJ) should increase nitric oxide bioavailability under conditions of muscle deoxygenation and acidosis that are a normal consequence of the maximal effort exercise test used to identify forearm critical impulse. We hypothesized BRJ would improve oxygen delivery:demand matching and forearm critical impulse performance. Healthy males (20.8 ± 2.4 years) participated in a randomized crossover trial between October 2017 and May 2018 (Queen's University, Kingston, ON). Participants completed 10 min of rhythmic maximal effort forearm handgrip exercise 2.5 h post placebo (PL) vs. BRJ (9 completed PL/BRJ vs. 4 completed BRJ/PL) within a 2 week period. Data are presented as mean ± SD. There was a main effect of drink (PL > BRJ) for oxygen extraction (<i>P</i> = 0.033, η<sub>p</sub><sup>2 </sup>= 0.351) and oxygen consumption/force (<i>P</i> = 0.017, η<sub>p</sub><sup>2 </sup>= 0.417). There was a drink × time interaction (PL > BRJ) for oxygen consumption/force (<i>P</i> = 0.035, η<sub>p</sub><sup>2 </sup>= 0.216) between 75 and 360 s (1.25-6 min) from exercise onset. BRJ did not influence oxygen delivery (<i>P</i> = 0.953, η<sub>p</sub><sup>2 </sup>= 0.000), oxygen consumption (<i>P</i> = 0.064, η<sub>p</sub><sup>2 </sup>= 0.278), metabolites ((lactate) (<i>P</i> = 0.196, η<sub>p</sub><sup>2 </sup>= 0.135), pH (<i>P</i> = 0.759, η<sub>p</sub><sup>2 </sup>= 0.008)) or power-duration performance parameters (critical impulse (<i>P</i> = 0.379, <i>d</i> = 0.253), W' (<i>P</i> = 0.733, <i>d</i> = 0.097)). BRJ during all-out handgrip exercise does not influence oxygen delivery or exercise performance. Oxygen cost of contraction with BRJ is reduced as contraction impulse is declining during maximal effort exercise resulting in less oxygen extraction.</p>","PeriodicalId":93878,"journal":{"name":"Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140904355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}