Files and links (1)
CC BY V4.0, Open Access
Journal article
Maintenance of internal load despite a stepwise reduction in external load during moderate intensity heart rate clamped cycling with acute graded normobaric hypoxia in males
Journal of science and medicine in sport, Vol.26(11), pp.P628-P635
2023
Abstract
Objectives
To investigate the acute effects of graded hypoxia on external and internal loads during 60 min of endurance cycling at a clamped heart rate.
Design
Repeated measures.
Methods
On separate visits, 16 trained males cycled for 60 min at a clamped heart rate corresponding to 80 % of their first ventilatory threshold at sea-level and 2500 m, 3000 m, 3500 m and 4000 m simulated altitudes (inspired oxygen fractions of 20.9 %, 15.4 %, 14.5 %, 13.6 % and 12.7 %, respectively). Markers of external (power output) and internal (blood lactate concentration, tissue saturation index, cardio-respiratory and perceptual responses) loads were measured every 15 min during cycling. Neuromuscular function of knee extensors was characterised pre- and post-exercise.
Results
Compared to sea-level (101 ± 22 W), there was a stepwise reduction in power output with increasing hypoxia severity (− 17.9 ± 8.9 %, − 27.1 ± 10.7 %, − 34.2 ± 12.0 % and − 44.6 ± 15.1 % at 2500 m, 3000 m, 3500 m, and 4000 m, respectively, all p < 0.05). Blood lactate and tissue saturation index were not different across hypoxia severities, and perceptual responses were exacerbated at 4000 m only, with increased breathing difficulty. Knee extensor torque decreased post-exercise (− 14.5 ± 9.0 %, p < 0.05), independent of condition.
Conclusions
Increasing hypoxia severity reduces cycling power output and arterial oxygen saturation in a stepwise fashion without affecting exercise responses between sea-level and simulated altitudes up to 3500 m despite breathing difficulty being elevated at 4000 m.
Details
- Title
- Maintenance of internal load despite a stepwise reduction in external load during moderate intensity heart rate clamped cycling with acute graded normobaric hypoxia in males
- Authors/Creators
- Siu Nam Li - The University of Western AustraliaPeter Peeling - The University of Western AustraliaBrendan R. Scott - Murdoch University, Centre for Healthy AgeingJeremiah J. Peiffer - Murdoch University, Centre for Healthy AgeingAlex Shaykevich - Perron Institute for Neurological and Translational ScienceOlivier Girard - The University of Western Australia
- Publication Details
- Journal of science and medicine in sport, Vol.26(11), pp.P628-P635
- Publisher
- Elsevier Ltd on behalf of Sports Medicine Australia.
- Identifiers
- 991005609668407891
- Copyright
- © 2023 The Author(s).
- Murdoch Affiliation
- Centre for Healthy Ageing; Murdoch Applied Sports Science Laboratory
- Language
- English
- Resource Type
- Journal article
UN Sustainable Development Goals (SDGs)
This output has contributed to the advancement of the following goals:
Metrics
26 File views/ downloads
113 Record Views