Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes
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.
RAS ID
64560
Document Type
Journal Article
Date of Publication
1-1-2023
Volume
124
Funding Information
NHS Laboratories Menarini (France)
School
School of Medical and Health Sciences / Centre for Exercise and Sports Science Research
Copyright
subscription content
Publisher
Springer
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, 124, 651-665. https://doi.org/10.1007/s00421-023-05346-6