Changes in serum enzyme levels after exercise in trained and untrained subjects

Twenty-eight healthy trained and untrained men and eleven untrained women were exercised at several grades on a treadmill or in various athletic events. The serum levels of five enzymes (two transaminases, aldolase, and two dehydrogenases) were compared prior to and at intervals after work. Generally there was a rise after exercise which reached its peak 5 min after completion of the work. The greatest increment of enzyme increase was observed in the untrained subjects and the least in the trained athletes. As the total amount of work output increased the mean serum enzyme levels were correspondingly raised. Aldolase and lactic dehydrogenase showed the least change, malic dehydrogenase increased moderately, while the two transaminases manifested very significant rises after all forms of exercise. Submitted on September 5, 1961