Prior arm exercise speeds the VO2 kinetics during arm exercise above the heart level.
OBJECTIVE
To test the hypothesis that the initial O2 uptake kinetics during exercise where the rise in blood flow (and, by implication, O2 delivery) to the working muscles during an abrupt increase in exercise intensity is reduced (i.e., arm exercise performed above the level of the heart) would be faster when preceded by a bout of high-intensity exercise.


METHODS
Eleven physically active males completed two protocols, each consisting of two consecutive bouts of 6 min of high-intensity arm crank exercise separated by 6 min of recovery. In one protocol, the arm crank exercise was performed with the arms below the level of the heart (<HL); in the other, the arms were above the level of the heart (>HL).


RESULTS
In the <HL protocol, the VO2 fast component time constant was not significantly affected by prior exercise (35.9+/-8.7 and 35.5+/-8.9 s in bouts 1 and 2, respectively). The amplitudes of the VO2 fast and slow component were respectively significantly higher and significantly lower in the second bout. In the >HL protocol, the amplitudes of the VO2 fast and slow component were unaffected by prior exercise, whereas the VO2 fast component time constant was significantly reduced in the second bout (49.8+/-22.1 vs 40.7+/-13.2 s; P<0.05).


CONCLUSIONS
The results of this study demonstrate that prior high-intensity exercise caused a significant speeding of the VO2 fast component response during subsequent high-intensity arm crank exercise performed above, and not below, the level of the heart.
Koppo
Katrien
K
Department of Movement and Sports Sciences, Ghent University, Ghent, BELGIUM. katrien.koppo@UGent.be
Bouckaert
Jacques
J
D000328:Adult; D001132:Arm; D001944:Breath Tests; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test / Q000379:methods*; D006801:Humans; D007700:Kinetics; D019344:Lactic Acid / Q000097:blood; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology
D019344:Lactic Acid