Plasma lactate dehydrogenase and creatine kinase after anaerobic exercise.

Eight untrained men performed 15-s and 60-s high-intensity exercise on a bicycle ergometer. Activities of the creatine kinase (CK) and lactate dehydrogenase (LDH) were measured in blood 3 min and 2, 6, and 24 h after cessation of exercise. The results indicate that anaerobic exercise induces a transient increase in plasma LDH activity and a more prolonged elevation in plasma CK activity. A negative correlation was found between CK activity measured before and 3 min after exercise and mean power, and total external work performed in both test types. A similar correlation was ascertained between pre- and post-exercise CK activity and maximal power output measured in the 60-s test. After the 15-s exercise test, only post-exercise plasma CK activity was negatively correlated with the maximal power output.