Owen T Payne, Michael G Leahy, Jamie F Burr, Jeremy D Road, Donald C McKenzie, A William Sheel
{"title":"NO EFFECT OF AEROBIC FITNESS ON EXERCISE-INDUCED DIAPHRAGM FATIGUE IN FEMALES.","authors":"Owen T Payne, Michael G Leahy, Jamie F Burr, Jeremy D Road, Donald C McKenzie, A William Sheel","doi":"10.1152/japplphysiol.00239.2024","DOIUrl":null,"url":null,"abstract":"<p><p>We tested the hypothesis that the incidence and magnitude of diaphragm fatigue following high-intensity exercise would be lower in females with a high aerobic capacity (Hi-Fit) compared to healthy females with an average aerobic fitness (Avg-Fit). Participants were assigned to groups based on their peak O<sub>2</sub> uptake (V̇O<sub>2peak</sub>) obtained during cycle exercise: Hi-Fit n=9, V̇O<sub>2peak</sub> <u>></u> 56.1±3.4 mL·kg<sup>-1</sup>·min<sup>-1</sup> vs. Avg-Fit n=9, V̇O<sub>2peak</sub> <u><</u> 35.7±4.9 mL·kg<sup>-1</sup>·min<sup>-1</sup>. On a second day, diaphragm fatigue was assessed before and after constant load exercise test to exhaustion. Magnetic stimulation of the phrenic nerve roots was used to non-volitionally assess diaphragm fatigue by measurement of transdiaphragmatic twitch pressure (P<sub>di,tw</sub>). Both groups exercised at > 90% of V̇O<sub>2peak</sub> for a similar duration (Hi-Fit: 546.1 ± 177.8 <i>vs</i> Avg-Fit: 559.3 ± 175.0 seconds, p = 0.9). Diaphragm fatigue was defined as a <u>></u> 15% reduction in P<sub>di,tw</sub>, approximately 2 times greater than the coefficient of variation. The mean group average reduction in P<sub>di,tw</sub> following exercise in the Hi-Fit (17.5%) and Avg-Fit groups (12.2%) was not different between groups (p = 0.2). The Hi-Fit group performed exercise at a higher absolute work rate that elicited significantly greater ventilatory work and inspiratory muscle force output. The Hi-Fit group did not experience greater fatigue compared to the Avg-Fit group, which we attribute to a greater reliance on accessory respiratory muscle recruitment, to training-induced increases in the aerobic capacity of the diaphragm, or a combination of the two. In summary, aerobic fitness is not predictive of exercise-induced diaphragm fatigue in healthy females.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":null,"pages":null},"PeriodicalIF":3.3000,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of applied physiology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1152/japplphysiol.00239.2024","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
We tested the hypothesis that the incidence and magnitude of diaphragm fatigue following high-intensity exercise would be lower in females with a high aerobic capacity (Hi-Fit) compared to healthy females with an average aerobic fitness (Avg-Fit). Participants were assigned to groups based on their peak O2 uptake (V̇O2peak) obtained during cycle exercise: Hi-Fit n=9, V̇O2peak> 56.1±3.4 mL·kg-1·min-1 vs. Avg-Fit n=9, V̇O2peak< 35.7±4.9 mL·kg-1·min-1. On a second day, diaphragm fatigue was assessed before and after constant load exercise test to exhaustion. Magnetic stimulation of the phrenic nerve roots was used to non-volitionally assess diaphragm fatigue by measurement of transdiaphragmatic twitch pressure (Pdi,tw). Both groups exercised at > 90% of V̇O2peak for a similar duration (Hi-Fit: 546.1 ± 177.8 vs Avg-Fit: 559.3 ± 175.0 seconds, p = 0.9). Diaphragm fatigue was defined as a > 15% reduction in Pdi,tw, approximately 2 times greater than the coefficient of variation. The mean group average reduction in Pdi,tw following exercise in the Hi-Fit (17.5%) and Avg-Fit groups (12.2%) was not different between groups (p = 0.2). The Hi-Fit group performed exercise at a higher absolute work rate that elicited significantly greater ventilatory work and inspiratory muscle force output. The Hi-Fit group did not experience greater fatigue compared to the Avg-Fit group, which we attribute to a greater reliance on accessory respiratory muscle recruitment, to training-induced increases in the aerobic capacity of the diaphragm, or a combination of the two. In summary, aerobic fitness is not predictive of exercise-induced diaphragm fatigue in healthy females.
期刊介绍:
The Journal of Applied Physiology publishes the highest quality original research and reviews that examine novel adaptive and integrative physiological mechanisms in humans and animals that advance the field. The journal encourages the submission of manuscripts that examine the acute and adaptive responses of various organs, tissues, cells and/or molecular pathways to environmental, physiological and/or pathophysiological stressors. As an applied physiology journal, topics of interest are not limited to a particular organ system. The journal, therefore, considers a wide array of integrative and translational research topics examining the mechanisms involved in disease processes and mitigation strategies, as well as the promotion of health and well-being throughout the lifespan. Priority is given to manuscripts that provide mechanistic insight deemed to exert an impact on the field.