Thermic effect of food at rest and following swim exercise in trained college men and women.

The calorigenic effect of a liquid meal was studied in 8 (5 male, 3 female) lean, trained swimmers to assess the effect of swim exercise on dietary-induced thermogenesis. Metabolic rate was measured by indirect calorimetry under 3 conditions: (A) 4 h postexercise in the postabsorptive state; (B) 4 h of rest in the postprandial state, and (C) 4 h postexercise in the postprandial state. At 20 min postexercise metabolic rate had increased 22% over RMR; however, by 40 min postexercise it had returned to the preexercise level. Following both conditions B and C oxygen consumption (VO2) remained significantly elevated for 3 h. The mean rise in caloric expenditure was 24.8 kcal/h when exercise preceded the meal, compared to 20.2 kcal/h when exercise was not performed. This difference of approximately 18 kcal/4 h, although of negligible importance in short-term energy balance, could be significant in long-term energy regulation, and thus contribute to body weight control.