Exercise effect on certain biochemical factors in the plasma in untrained subjects and in systematically trained cyclists.

Thirty-seven cyclists participating in long-distance road races were exposed to maximal exercise closely before the onset of racing season. Forty young males (medical students) of average physical fitness had similar exposure. In both groups determinations of the concentrations of free acids, glucose, amino acid nitrogen and lactate in the plasma of venous blood were done before the exercise, immediately after it, and in the 15th and 30th minutes of restitution. The differences between both groups were compared using the t test of Student. It was found that during maximal exercise glucose concentration increased more in the trained subjects than in the untrained ones, and remained increased at the restitution time. In the untrained subjects the concentrations of PFA and amino acid nitrogen decreased after the exercise, while in the group of cyclists it showed no significant changes. In contrast to the untrained group in the group of cyclists FFA concentrations decreased during restitution. Despite similar increase in heart rate and similar value of maximal workload in both groups the concentration of lactate was significantly lower in the group of cyclists.