Severity of arterial hypoxaemia affects the relative contributions of peripheral muscle fatigue to exercise performance in healthy humans

Markus Amann, Lee M. Romer, Andrew W. Subudhi, David F. Pegelow and Jerome A. Dempsey

This study examined the effects of hypoxia severity on peripheral versus central determinants of exercise performance. Eight cyclists performed constant-load exercise to exhaustion at various fractions of inspired O2 fraction. At task failure arterial hypoxaemia was surreptitiously reversed via acute O2 supplementation and subjects were encouraged to continue exercising. Peripheral fatigue was assessed via changes in potentiated quadriceps twitch force as measured pre- versus post-exercise in response to supramaximal femoral nerve stimulation. The results showed that at task failure in normoxia and moderate hypoxia, hyperoxygenation had no significant effect on prolonging endurance time. However, following task failure in severe hypoxia, hyperoxygenation elicited a significant prolongation of time to exhaustion. Following further investigation the authors were able to conclude that across the range of normoxia to severe hypoxia, the major determinants of central motor output and exercise performance switches from a predominantly peripheral origin of fatigue to a hypoxia-sensitive central component of fatigue, probably involving brain hypoxic effects on effort perception.

Journal of Physiology, 2007, 581, 1, 389-404.

View Abstract

Link to full article

Stroke Course

Every physiotherapist will work with someone who has had a stroke during their career. Gain a deeper understanding based on the latest evidence and become a better clinician.
News article posted by: Rachael Lowe

Rachael Lowe is Co-Founder and Executive Director of Physiopedia. A physiotherapist and technology specialist Rachael has been working with Physiopedia since 2008 to create a resource that provides universal access to physiotherapy knowledge as well as a platform for connecting and educating the global physiotherapy profession.

Speak Your Mind