Enzyme Activities in Serum after Extensive Exercise, with Special Reference to Creatine Kinase MB

Abstract

Elevations of serum enzymes used as criteria in establishing the diagnosis of [human] acute myocardial infarction (AMI) often show a pattern of AMI after physical exercise without other clinical signs of myocardial damage. Since a clinical condition resembling AMI sometimes appears after strenuous physical exercise, this study was designed to show if the new, almost heart-specific, isoenzyme creatine kinase MB (CK-MB) would solve the diagnostic problems. Ten well-trained volunteers took part in a 26 km jogging race. None of them had any cardiovascular symptoms, but the old cardiac enzymes rose in some of them above the discriminatory levels, whereas CK-MB was below these levels in all cases. CK-MB determination is a valuable diagnostic tool in patients who have recently exercised extensively.