Effect of exercise on recovery changes in plasma levels of FFA, glycerol, glucose and catecholamines.

The prolonged effects of acute exercise on the plasma concentrations of FFA, glycerol, glucose and catecholamines were examined. Twelve young men performed exhaustive prolonged exercise on a cycle ergometer (80 minutes at 70-75% of VO2 max), and in separate experiments they exercised for shorter durations (20, 40 and 80 minutes) and at lesser intensities (29, 50 and 75% of VO2 max). Carbohydrate-rich meals were given 2, 7 and 12 hours after exercise. Blood samples were taken while the subjects rested in bed during a 12-14-hour recovery period. Control experiments without exercise were also performed. In some subjects the plasma concentration of FFA after exhaustive exercise was increased to levels considered to be potentially hazardous, and the mean plasma level of FFA was increased for 6 hours and that of glycerol was increased for 2.5 hours after exercise. The plasma concentration of glucose was generally reduced for 12 hours after exhaustive exercise. Plasma catecholamines were increased for 2 hours after exhaustive exercise. We observed a preprandial increase in FFA and glycerol concentrations during recovery from exercise which was related to the duration and intensity of exercise. These findings indicate that the rates of FA utilization and TG-FA substrate cycling were increased in the recovery period after exercise, and that the magnitude of both depends on the duration and intensity of exercise.