Biochemical changes after a 100 km hill walk.

Biochemical changes after a 100 km hill walk were studied in 16 subjects (nine male and seven female). Plasma concentrations of potassium, albumin and total protein were lower, and the concentrations of phosphate, urea, alanine transaminase (ALT) and bilirubin were higher after the walk than before. Activities of creatine kinase (CK), lactate dehydrogenase (LD) and their isoenzymes CKMB and LD1 increased several fold after the walk. Although CKMB increased, the relative amount of CKMB was less than that seen in myocardial infarction. We conclude that after a 100 km hill walk there is evidence of plasma volume expansion, muscle damage, and increased protein breakdown.