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Carbon monoxide inhalation reduces skeletal muscle fatigue resistance
Author(s) -
Morse C. I.,
Pritchard L. J.,
Wüst R. C. I.,
Jones D. A.,
Degens H.
Publication year - 2008
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2007.01757.x
Subject(s) - inhalation , isometric exercise , anesthesia , muscle fatigue , medicine , carbon monoxide , cardiology , chemistry , electromyography , physical medicine and rehabilitation , biochemistry , catalysis
Aim: To determine whether inhalation of carbon monoxide (CO), resulting in carboxyhaemoglobin (COHb) levels observed in smokers, had an effect on muscle fatigue during electrically evoked and voluntary muscle contractions. Methods: Young non‐smoking males inspired CO from a Douglas bag until their COHb level reached 6%. During the control condition the same participants inspired ambient air from a Douglas bag for 6 min. Fatigue was assessed as the decline in torque in isometric knee extensions, during 2 min of electrically evoked contractions (30 Hz, 1 s on, 1 s off) and during 2 min of maximal isometric voluntary contractions (1 s on, 1 s off). A fatigue index (FI) was calculated as the ratio of final torque : initial torque. Time to peak torque (TPT) and half relaxation time (½RT) were also determined for the electrically evoked contractions. Results: The FI during both the voluntary fatigue test (control: 0.80 ± 0.09 vs. CO: 0.70 ± 0.08; mean ± SD) and that of the fatigue test with electrically evoked contractions (control: 0.61 ± 0.09 vs. CO: 0.53 ± 0.12) was significantly lower after CO inhalation than after inhalation of ambient air ( P < 0.05). There was, however, no effect of CO on the changes in TPT or ½RT during the fatigue test. Conclusion: Carbon monoxide inhalation resulting in COHb levels found in smokers has an acute impact on the ability of the muscle to resist fatigue.