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The effect of severe and moderate hypoxia on exercise at a fixed level of perceived exertion

Lookup NU author(s): Dr Owen JeffriesORCiD

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This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).

Abstract

PurposeThe purpose of this study was to determine the primary cues regulating perceived effort and exercise performance using a fixed-RPE protocol in severe and moderate hypoxia.MethodsEight male participants (26 ± 6 years, 76.3 ± 8.6 kg, 178.5 ± 3.6 cm, 51.4 ± 8.0 mL kg^{− 1} min^{− 1}V˙O_2max) completed three exercise trials in environmental conditions of severe hypoxia (F_IO₂ 0.114), moderate hypoxia (F_IO₂ 0.152), and normoxia (F_IO₂ 0.202). They were instructed to continually adjust their power output to maintain a perceived effort (RPE) of 16, exercising until power output declined to 80% of the peak 30-s power output achieved.ResultsExercise time was reduced (severe hypoxia 428 ± 210 s; moderate hypoxia 1044 ± 384 s; normoxia 1550 ± 590 s) according to a reduction in F_IO₂ (P < 0.05). The rate of oxygen desaturation during the first 3 min of exercise was accelerated in severe hypoxia (− 5.3 ± 2.8% min^{− 1}) relative to moderate hypoxia (− 2.5 ± 1.0% min^{− 1}) and normoxia (− 0.7 ± 0.3% min^{− 1}). Muscle tissue oxygenation did not differ between conditions (P > 0.05). Minute ventilation increased at a faster rate according to a decrease in F_IO₂ (severe hypoxia 27.6 ± 6.6; moderate hypoxia 21.8 ± 3.9; normoxia 17.3 ± 3.9 L min^{− 1}). Moderate-to-strong correlations were identified between breathing frequency (r = − 0.718, P < 0.001), blood oxygen saturation (r = 0.611, P = 0.002), and exercise performance.ConclusionsThe primary cues for determining perceived effort relate to progressive arterial hypoxemia and increases in ventilation.

Publication metadata

Author(s): Jeffries O, Patterson SD, Waldron M

Publication type: Article

Publication status: Published

Journal: European Journal of Applied Physiology

Year: 2019

Volume: 119

Pages: 1213-1224

Print publication date: 01/05/2019

Online publication date: 01/03/2019

Acceptance date: 21/02/2019

Date deposited: 01/03/2019

ISSN (print): 1439-6319

ISSN (electronic): 1439-6327

Publisher: Springer

URL: https://doi.org/10.1007/s00421-019-04111-y

DOI: 10.1007/s00421-019-04111-y

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