Recovery from dynamic exercise.

Minimal information is available on the basic interactions within the metabolic and cardiovascular systems during recovery from exercise. Nine men participated in three experiments: one control and two cost-equivalent (52 liters O2) exercise tests of 30 (EX30) and 45 (EX45) min. Exercise intensities were adjusted accordingly. During recovery, all parameters reestablished baseline levels within 10 min, except for heart rate (30 min). Correlations for each parameter for EX30 and EX45 were obtained by evaluating each subject's exercise cost and recovery "payback." A split, two-factor analysis of variance was run separately on the "fast" (minutes 1-7) and "slow" (minutes 10-60) phases of recovery to determine if the time course of recovery was related to exercise intensity. It was concluded that for a work cost of approximately 300 kcal, 1) the slow phase of recovery was unaffected by the exercise intensity, 2) the fast phase of cardiovascular recovery was unaffected by exercise intensity while minute ventilation and O2 and CO2 uptake were affected, and 3) cardiac output and the ventilatory equivalents for O2 and CO2 correlated well between work cost and recovery payback.