Jeremy Rabineau, Eric T Hedge, Roxanne Fournier, Carmelo J Mastrandrea, Richard L Hughson
{"title":"Heart rate variability during exercise can quantify cardiorespiratory deconditioning in 55- to 65-yr-old men and women exposed to head-down bed rest.","authors":"Jeremy Rabineau, Eric T Hedge, Roxanne Fournier, Carmelo J Mastrandrea, Richard L Hughson","doi":"10.1152/japplphysiol.00017.2025","DOIUrl":null,"url":null,"abstract":"<p><p>The heart rate variability (HRV) features HRV<sub>0.75</sub> and HRV<sub>0.5</sub>, obtained by detrended fluctuation analysis during incremental cycle ergometer tests, have been shown to correlate with indices of cardiorespiratory fitness. Here, we evaluate the ability of these features to track individual changes in cardiorespiratory fitness induced by head-down bed rest (HDBR) among late middle-aged adults. Twenty-two healthy participants (55-65 yr old, 11 women) were exposed to 14-day HDBR. Eleven participants were assigned to a group performing daily aerobic and resistive exercises during HDBR, whereas the others were assigned to a control group with no countermeasure intervention. We measured gas exchange and electrocardiography during incremental cycle ergometer tests pre- and post-HDBR. The countermeasure preserved oxygen uptake (V̇o<sub>2</sub>) at the two ventilatory thresholds (VT1 and VT2), HRV<sub>0.75</sub> and HRV<sub>0.5</sub>. However, these four features decreased in the control group after HDBR. A large and proportional bias was evidenced between V̇o<sub>2</sub> at VT1 and HRV<sub>0.75</sub>, which was less the case for V̇o<sub>2</sub> at VT2 versus HRV<sub>0.5</sub>. However, the intraindividual changes in the control group were correlated (<i>r</i><sub>rm</sub> = 0.66 for VT1 vs. HRV<sub>0.75</sub> and <i>r</i><sub>rm</sub> = 0.82 for V̇o<sub>2</sub> at VT2 vs. HRV<sub>0.5</sub>, both <i>P</i> < 0.001). Overall, this study indicated that HRV<sub>0.75</sub> and HRV<sub>0.5</sub> can be used to longitudinally monitor changes in cardiorespiratory fitness in late middle-aged adults with physical deconditioning. Future research can apply these methods to other study populations.<b>NEW & NOTEWORTHY</b> We report the applicability of two heart rate variability features (HRV<sub>0.75</sub>, HRV<sub>0.5</sub>) computed during exercise to assess changes in cardiorespiratory fitness. Although previous cross-sectional studies suggested that these features were highly correlated to the ventilatory thresholds, we highlight the fact that they should not be considered as equivalent. More easily obtained than ventilatory thresholds, HRV<sub>0.75</sub> and HRV<sub>0.5</sub> could be used as fitness markers along a continuum of the physiological response between rest and maximal exercise.</p>","PeriodicalId":15160,"journal":{"name":"Journal of applied physiology","volume":" ","pages":"1002-1010"},"PeriodicalIF":3.3000,"publicationDate":"2025-04-01","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.00017.2025","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/3/18 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"PHYSIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The heart rate variability (HRV) features HRV0.75 and HRV0.5, obtained by detrended fluctuation analysis during incremental cycle ergometer tests, have been shown to correlate with indices of cardiorespiratory fitness. Here, we evaluate the ability of these features to track individual changes in cardiorespiratory fitness induced by head-down bed rest (HDBR) among late middle-aged adults. Twenty-two healthy participants (55-65 yr old, 11 women) were exposed to 14-day HDBR. Eleven participants were assigned to a group performing daily aerobic and resistive exercises during HDBR, whereas the others were assigned to a control group with no countermeasure intervention. We measured gas exchange and electrocardiography during incremental cycle ergometer tests pre- and post-HDBR. The countermeasure preserved oxygen uptake (V̇o2) at the two ventilatory thresholds (VT1 and VT2), HRV0.75 and HRV0.5. However, these four features decreased in the control group after HDBR. A large and proportional bias was evidenced between V̇o2 at VT1 and HRV0.75, which was less the case for V̇o2 at VT2 versus HRV0.5. However, the intraindividual changes in the control group were correlated (rrm = 0.66 for VT1 vs. HRV0.75 and rrm = 0.82 for V̇o2 at VT2 vs. HRV0.5, both P < 0.001). Overall, this study indicated that HRV0.75 and HRV0.5 can be used to longitudinally monitor changes in cardiorespiratory fitness in late middle-aged adults with physical deconditioning. Future research can apply these methods to other study populations.NEW & NOTEWORTHY We report the applicability of two heart rate variability features (HRV0.75, HRV0.5) computed during exercise to assess changes in cardiorespiratory fitness. Although previous cross-sectional studies suggested that these features were highly correlated to the ventilatory thresholds, we highlight the fact that they should not be considered as equivalent. More easily obtained than ventilatory thresholds, HRV0.75 and HRV0.5 could be used as fitness markers along a continuum of the physiological response between rest and maximal exercise.
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.