Exercise and serum enzymes

Abstract

Numerous studies on serum enzymes derived from skeletal muscle, such as CK, AST, LDH, are also being reported in the field of sports medicine. In this article, I would like to summarize the findings on "physical exercise and serum enzymes" studied up to the present. Secondly, I will evaluate the usefulness and limits as indicators of condition and muscle fatigue in athletes. The amount of change and time course of CK, AST, LDH and myoglobin responses were markedly different in 5-km, marathon and triathalon races, and in trained and untrained subjects. Trained subjects showed peaks of these enzymes one day after endurance running, and untrained subjects had a typical biphasie variation after endurance running. The typical change in untrained subjects might reflect a series of different histopathological changes, including muscle damage, repair and regeneration of muscles. In participants of women's marathon races, higher ranking prize winners showed lower levels before and lower increases in CK activity after the race than the other participants. Higher serum CK activity above 300 mU/ml accompanied by increases in serum myosin light chain I (MLC I) concentration (above 2.5 ng/ml) without increases in troponin T and CK-MB were observed during marathon, triathalon, 100-km and 250-km ultra marathon races. The athletes who showed a higher serum CK activity above 500 mU/ml at the pre-race stage felt subjective fatigue and some dropped out from the race. Normal persons who had a lower CK activity below 40-50 mU/ml indicated lower levels of serum HDL-C and physical fitness (V̇O2max). On the contrary, persons who showed a higher CK level of 100-200 mU/ml or more had higher levels of HDL-C and V̇O2max. Measurement of serum CK activity might provide useful information for checking health and physical fitness levels in normal persons, and also the physical and subjective conditions of athletes.