Differential effects of maximal- and moderate-intensity runs on plasma leptin in healthy trained subjects

This study investigated the effect of different exercise bouts on plasma le ptin response. Trained men (n = 9) performed a short duration, maximal inte nsity (MAX) bout and a 60-min endurance run at similar to 70% of maximal ox ygen consumption (END). Blood was collected before, immediately after, 24 h after (24 h Post), and 48 h after exercise (48 h Post) for measurement of plasma leptin, insulin,;and glucose. VO(2)max and percent body fat were 57. 8 +/- 2.1 mL.kg(-1).min(-1) and 10.8 +/- 1.5% (mean +/- SEM), respectively. Energy expenditure was 197.5 +/- 11.8 and 882.7 +/- 14.4 kcal for MAX and END, respectively. Plasma leptin levels did not differ between time points for the MAX run. Leptin was significantly lower 48 h Post (2.2 +/- 0.3 ng/m L) versus before, immediately after, and 24 h Post exercise(3.1 +/- 0.3, 3. 0 +/- 0.3, and 2.5 +/- 0.4 ng/mL, respectively) for END. Leptin tended to b e lower at 24 h Post than before or immediately after exercise (P = 0.10). Plasma insulin was lower 24 h Post- versus preexercise for the END, but was not correlated to changes in leptin levels. Plasma glucose levels did not change significantly during the endurance test. We found a delayed decrease in leptin at 48 h after an extended exercise session (900 kcal). Furthermo re, this effect did not appear to be related to changes in insulin or gluco se levels. Findings from this study address the effects of exercise on lept in, aiding in the evaluation of the impact of exercise and energy expenditu re on plasma leptin concentrations in the prevention and treatment of obesi ty.