Effects of prior heavy exercise on phase II pulmonary oxygen uptake kinetics during heavy exercise

Abstract

We tested the hypothesis that heavy-exercise phase II oxygen uptake (VO(2)) kinetics could be speeded by prior heavy exercise. Ten subjects performed four protocols involving 6-min exercise bouts on a cycle ergometer separated by 6 min of recovery: 1) moderate followed by moderate exercise; 2) moderate followed by heavy exercise; 3) heavy followed by moderate exercise; and 4) heavy followed by heavy exercise. The VO(2) responses were modeled using two (moderate exercise) or three (heavy exercise) independent exponential terms. Neither moderate- nor heavy-intensity exercise had an effect on the VO(2) kinetic response to subsequent moderate exercise. Although heavy-intensity exercise significantly reduced the mean response time in the second heavy exercise bout (from 65.2 +/- 4.1 to 47.0 +/- 3.1 s; P < 0.05), it had no significant effect on either the amplitude or the time constant (from 23.9 +/- 1.9 to 25.3 +/- 2.9 s) of the VO(2) response in phase II. Instead, this "speeding" was due to a significant reduction in the amplitude of the VO(2) slow component. These results suggest phase II VO(2) kinetics are not speeded by prior heavy exercise.

l-Citrulline supplementation improves O2 uptake kinetics and high-intensity exercise performance in humans

“…Moderate-intensity step tests were completed to assess V O2 kinetics and cycling economy in the absence of a V O2 slow component, while severeintensity step tests were completed to assess V O2 kinetics in the presence of a V O2 slow component, where V O2 max is attained and the tolerable duration of exercise is Ͻ20 min (49,66). We conducted repeated step tests on the same laboratory visit, since a prior moderate-intensity step exercise bout does not affect V O2 kinetics during subsequent moderate-or severe-intensity cycle exercise (12,17). Therefore, all subjects performed a total of four bouts of moderateintensity exercise and two bouts of severe-intensity exercise for each experimental condition.…”

Efeito da intensidade do exercício prévio na resposta fisiológica e na performance aeróbia de curta duração

“…However, the cardiorespiratory and metabolic responses to exercise, particularly those of submaximal intensity (i.e., <VO 2 max), may be heterogeneous to a certain percentage of the VO 2 max 13,17,18 . As a result, many studies that have investigated the effects of prior exercise have used the concept of exercise intensity domains to individualize exercise responses 3,[5][6][7][8][9][10][11] . Using [La] and VO 2 responses during constant workload exercise, three different exercise intensity domains (moderate, heavy and severe) can be characterized 18 .…”

“…Depending on intensity, the subsequent exercise performance may not modify, improve or even decreases 23 . The diversity of these responses is a function of the different conditions generated by prior exercise on parameters such as [La], VO 2 , blood flow and recruitment of motor units 3,9,24 . The different effects of prior exercise are described below, according to the domain where they are performed.…”

“…This type of intervention has attracted much attention from researchers and coaches in the last decades [1][2][3][4][5] . In general, studies that have investigated the effects of prior exercises have used relatively short durations (5-15 min) and intensity varies according to the characteristics of the subsequent exercise.…”

“…Aerobic performance (i.e., time to perform a given distance) and exercise tolerance, i.e., time limit (tlim, maximum exercise time with constant intensity that can be performed without or with different types of pauses, e.g., active or passive) are improved, especially in high-intensity and shortduration exercises (up to 2-9 min approximately) [8][9][10][11] . With respect to cardiorespiratory parameters, it has been shown that after prior exercise, the oxygen uptake kinetics (VO 2 ) response at the beginning of exercise can be accelerated 3,4,6,8 because the increased blood flow and the more homogeneous distribution of the muscle blood flow tend to provide greater O 2 delivery to active muscles 2,4,12 . The O 2 extraction by active muscles is increased, reducing demand for alactic and lactic anaerobic systems.…”