In the recovery period after strenuous exercise there is a prolonged increase in oxygen uptake termed the excess postexercise oxygen consumption(EPOC) which may last for 24 h after exercise. It is possible that this may lead to a chronic elevation in resting metabolism in athletes training twice every day, which elite endurance athletes often do. However, the effect on resting metabolism of performing strenous exercise before recovery from a previous exercise bout is complete has not been studied previously. Therefore we examined the effect of one versus two daily bouts of exercise on EPOC, as well as the effect of a short or long recovery period between exercise bouts. Nine well trained young men (5 speedskaters and 4 triathletes; age: 23±2 (SD); maximal O2-uptake: 69.1±3.7 ml·min-1·kg-1) went through four different 24 h experiments starting at 7 AM with either one exercise bout (ONE), two exercise bouts with 3 h recovery between bouts (SHORT), two bouts with 6 h recovery(LONG), or a control experiment with bedrest and no exercise (REST). Except for the exercise bouts the subjects rested in bed and the final exercise bout each day was always completed at 16.30 PM. Each exercise bout consisted of 65 min at 75% of maximal O2-uptake on a cycle ergometer followed by bedrest. O2-uptake was measured continuously for the 1st h after exercise and then for 10 min every hour until 21.30 PM, and again at 7.00 AM the next morning. EPOC was calculated as the accumulated difference in O2-uptake for the 5 h recovery period (16.30-21.30) between the control and exercise experiments. EPOC (±SE) was 10.3±2.9 1 in ONE(p<0.0004 vs REST, t-test), 17.1±2.5 l in LONG (p<0.0001 vs REST; p=0.06 vs ONE), and 20.2±3.7 l in SHORT (p<0.0001 vs REST; p=0.003 vs ONE, p=0.18 vs LONG). The next morning (14.5 h after exercise) O2-uptake was significantly elevated above the control experiment in all the exercise experiments, but there were no differences between the different exercise experiments (REST: 288±16 ml/min (SE); ONE: 318±9 ml/min; LONG: 336±11 ml/min; SHORT: 331±15 ml/min). We conclude that when a near-exhaustive endurance exercise bout is performed before recovery from a previous bout is complete, there is an increase in EPOC.
American College of Sports Medicine 45th Annual Meeting; June 3-6, 1998; Orange County Convention Center; Orlando, Florida
G-17 FREE COMMUNICATION/SLIDE PRESENTATION REST AND POST-EXERC METAB