The purpose of this study was to compare energy expenditure during the first 20 minutes of recovery after 20 and 40 minutes of exercise at 50 percent and 70 percent of [latin capital V with dot above]O2 max. Subjects were six male competitive distance runners (mean +/- standard deviation: age = 24.5 +/- 7.1 years, [latin capital V with dot above]O2 max = 67.0 +/- 3.5 ml*kg-1 *min-1). Open circuit spirometry was used to determine [latin capital V with dot above]O2. Subjects performed the four exercise conditions on separate days at the same time of day (+/- one hour), and were in a four-hour fasting state when tested. Recovery energy expenditure (REE) over 20 minutes and for each five-minute period in recovery was significantly greater (p < 0.01) after exercise at 70 percent of [latin capital V with dot above]O2 max than at 50 percent of [latin capital V with dot above]O2 max, while no significant difference was found between the 20-minute and 40-minute durations. Interaction was significant, with the more intense and longer exercise yielding a higher REE than the lower intensity and shorter exercise. The REE above resting level for 20 minutes under the four conditions ranged from 46.2 to 75.9 kilojoules. Within the conditions studied, it was concluded that exercise intensity is more important than exercise duration in determining REE.
(C) 1991 National Strength and Conditioning Association