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The Effects of Exercise Intensity vs. Metabolic State on the Variability and Magnitude of Left Ventricular Twist Mechanics during Exercise

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posted on 2023-02-06, 13:51 authored by Craig Armstrong, Jake Samuel, Andrew Yarlett, Stephen-Mark Cooper, Michael StembridgeMichael Stembridge, Eric J. Stöhr

 Increased left ventricular (LV) twist and untwisting rate (LV twist mechanics) are essential responses of the heart to exercise. However, previously a large variability in LV twist mechanics during exercise has been observed, which complicates the interpretation of results. This study aimed to determine some of the physiological sources of variability in LV twist mechanics during exercise. Sixteen healthy males (age: 22 ± 4 years, https://journals.plos.org/plosone/article/file?type=thumbnail&id=10.1371/journal.pone.0154065.e001O2peak: 45.5 ± 6.9 ml∙kg-1∙min-1, range of individual anaerobic threshold (IAT): 32–69% of https://journals.plos.org/plosone/article/file?type=thumbnail&id=10.1371/journal.pone.0154065.e002O2peak) were assessed at rest and during exercise at: i) the same relative exercise intensity, 40%peak, ii) at 2% above IAT, and, iii) at 40%peak with hypoxia (40%peak+HYP). LV volumes were not significantly different between exercise conditions (P > 0.05). However, the mean margin of error of LV twist was significantly lower (F2,47 = 2.08, P < 0.05) during 40%peak compared with IAT (3.0 vs. 4.1 degrees). Despite the same workload and similar LV volumes, hypoxia increased LV twist and untwisting rate (P < 0.05), but the mean margin of error remained similar to that during 40%peak (3.2 degrees, P > 0.05). Overall, LV twist mechanics were linearly related to rate pressure product. During exercise, the intra-individual variability of LV twist mechanics is smaller at the same relative exercise intensity compared with IAT. However, the absolute magnitude (degrees) of LV twist mechanics appears to be associated with the prevailing rate pressure product. Exercise tests that evaluate LV twist mechanics should be standardised by relative exercise intensity and rate pressure product be taken into account when interpreting results. 

History

Published in

PLoS ONE

Publisher

Public Library of Science

Version

  • VoR (Version of Record)

Citation

Armstrong, C., Samuel, J., Yarlett, A., Cooper, S-M, Stembridge, M., Stöhr, E.J. (2016) 'The effects of exercise intensity vs. metabolic state on the variability and magnitude of left ventricular twist mechanics during exercise', PLoS ONE 11(4): e0154065. doi:10.1371/journal.pone.0154065

Electronic ISSN

1932-6203

Cardiff Met Affiliation

  • Cardiff School of Sport and Health Sciences

Cardiff Met Authors

Stephen-Mark Cooper Mike Stembridge

Cardiff Met Research Centre/Group

  • Cardiovascular Physiology

Copyright Holder

  • © The Authors

Language

  • en

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