Effects of endurance training on hyperammonaemia during a 45-min constant exercise intensity.
Eleven laboratory-pretrained subjects (initial VO2max = 54 ml.kg-1.min-1) took part in a study to evaluate the effect of a short endurance training programme [8-12 sessions, 1 h per session, with an intensity varying from 60% to 90% maximal oxygen consumption (VO2max)] on the responses of blood ammonia (b[NH+4]) and lactate (b[la]) concentrations during progressive and constant exercise intensities. After training, during which VO2max did not increase, significant decreases in b[NH+4], b[la] and muscle proton concentration were observed at the end of the 80% VO2max constant exercise intensity, although b[NH+4] and b[la] during progressive exercise were unchanged. On the other hand, no correlations were found between muscle fibre composition and b[NH+4] in any of the exercise procedures. This study demonstrated that a constant exercise intensity was necessary to reveal the effect of training on muscle metabolic changes inducing the decrease in b[NH+4] and b[la]. At a relative power of exercise of 80% VO2max, there was no effect of muscle fibre composition on b[NH+4] accumulation.
Denis
C
C
Laboratoire de Physiologie, Faculté de Médecine, Université, Saint-Etienne, France.
Linossier
M T
MT
Dormois
D
D
Cottier-Perrin
M
M
Geyssant
A
A
Lacour
J R
JR
D000328:Adult; D000641:Ammonia / Q000097:blood*; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D009132:Muscles / Q000378:metabolism; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*
D007773:Lactates; D000641:Ammonia