Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes

Document Type

Journal Article

Publication Title

European Journal of Applied Physiology

Publisher

Springer

School

School of Medical and Health Sciences / Centre for Exercise and Sports Science Research

RAS ID

64560

Funders

NHS Laboratories Menarini (France)

Comments

Haddad, T., Mons, V., Meste, O., Dempsey, J. A., Abbiss, C. R., Brisswalter, J., & Blain, G. M. (2023). Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes. European Journal of Applied Physiology. Advance online publication. https://doi.org/10.1007/s00421-023-05346-6

Abstract

Introduction: We tested the hypothesis that breathing heliox, to attenuate the mechanical constraints accompanying the decline in pulmonary function with aging, improves exercise performance. Methods: Fourteen endurance-trained older men (67.9 ± 5.9 year, V O2max: 50.8 ± 5.8 ml/kg/min; 151% predicted) completed two cycling 5-km time trials while breathing room air (i.e., 21% O2–79% N2) or heliox (i.e., 21% O2–79% He). Maximal flow–volume curves (MFVC) were determined pre-exercise to characterize expiratory flow limitation (EFL, % tidal volume intersecting the MFVC). Respiratory muscle force development was indirectly determined as the product of the time integral of inspiratory and expiratory mouth pressure ( Pmouth) and breathing frequency. Maximal inspiratory and expiratory pressure maneuvers were performed pre-exercise and post-exercise to estimate respiratory muscle fatigue. Results: Exercise performance time improved (527.6 ± 38 vs. 531.3 ± 36.9 s; P = 0.017), and respiratory muscle force development decreased during inspiration (− 22.8 ± 11.6%, P < 0.001) and expiration (− 10.8 ± 11.4%, P = 0.003) with heliox compared with room air. EFL tended to be lower with heliox (22 ± 23 vs. 30 ± 23% tidal volume; P = 0.054). Minute ventilation normalized to CO2 production (V E/ V CO2) increased with heliox (28.6 ± 2.7 vs. 25.1 ± 1.8; P < 0.001). A reduction in MIP and MEP was observed post-exercise vs. pre-exercise but was not different between conditions. Conclusions: Breathing heliox has a limited effect on performance during a 5-km time trial in master athletes despite a reduction in respiratory muscle force development.

DOI

10.1007/s00421-023-05346-6

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