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The Decrease in the V˙O2 Slow Component Induced by Prior Exercise Does Not Affect the Time to Exhaustion

2002; Thieme Medical Publishers (Germany); Volume: 23; Issue: 4 Linguagem: Inglês

10.1055/s-2002-29080

1439-3964

Katrien Koppo, Jacques Bouckaert,

Physical Activity and Health

In previous studies decreases in the V˙O2 slow component were observed after prior heavy exercise. The observed effects after prior low-intensity exercise were rather controversial. The purpose of the present study was to more thoroughly examine the effects of prior low-intensity exercise on the V˙O2 slow component. Furthermore, it has been suggested that the V˙O2 slow component may be a determinant of exercise tolerance. Therefore we tested the hypothesis whether an attenuated V˙O2 slow component induced by prior exercise could affect the time to exhaustion. Ten subjects performed four exercise protocols consisting of heavy cycling exercise (95 % V˙O2peak) until exhaustion. This constant-load exercise was performed without prior exercise (protocol NPE), or was preceded by 6 min heavy cycling exercise (protocol 6HPE), 12 min low-intensity cycling exercise (protocol 12LPE) or 6 min low-intensity cycling exercise (protocol 6LPE). The V˙O2 slow component quantified as ΔV˙O2(end-2) (669 ± 90 ml × min-1 in NPE) was significantly reduced after heavy as well as low-intensity exercise (respectively 47 %, 29 % and 17 % in 6HPE, 12LPE and 6LPE). This reduction lead to a significantly lower end V˙O2 in 6HPE and 12LPE. The time to exhaustion (594 ± 139 s in NPE), however, was unaffected by prior exercise rejecting our hypothesis that the attenuated V˙O2 slow component could improve the capability to sustain exercise performance.