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- Title
Breathing a low-density gas reduces respiratory muscle force development and marginally improves exercise performance in master athletes.
- Authors
Haddad, Toni; Mons, Valentin; Meste, Olivier; Dempsey, Jerome A.; Abbiss, Chris R.; Brisswalter, Jeanick; Blain, Gregory M.
- 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.
- Subjects
RESPIRATORY muscles; MUSCLE growth; RESPIRATION; ENDURANCE athletes; MUSCLE fatigue; EXPIRATORY flow; OLDER men
- Publication
European Journal of Applied Physiology, 2024, Vol 124, Issue 2, p651
- ISSN
1439-6319
- Publication type
Article
- DOI
10.1007/s00421-023-05346-6