title: Effect of exercise on plasma pyruvate kinase and creatine kinase activity.
abstract: Plasma pyruvate kinase (PK) and creatine kinase (CK) were measured in healthy subjects engaging in (a) mild exercise, 30 min on an exercise cycle maintaining a pulse rate of 150/min, (b) moderate exercise, squeezing a ball until exhaustion with a sphygmomanometer cuff inflated above systolic pressure around the arm (max. 2 min) and (c) severe exercise, completing a marathon race. Mild exercise resulted in no change in enzyme levels over 24 h. Moderate exercise produced a small increase in PK but no change in CK. PK activity rose from 35.3 +/- 10 U/l pre-exercise to 41.3 +/- 13 U/l 15 min post-exercise (n = 8, p less than 0.025). Severe exercise (completing a marathon race) resulted in a 3-fold increase in PK from 26 (4-87) U/l pre-race to 69 (21-156) U/l immediately post-race, and also, as expected, an increase in CK from 60 (15-164) U/l to 257 (72-1535) U/l (results are means and ranges, n = 69, p less than 0.001 for both enzymes). Runners showed parallel increases in PK and CK (p less than 0.05 by Spearman rank correlation). The mean post-race activity of CK-MB was less than 5% of total CK but 18 runners had values greater than 6% (mean 4.8, range 1-18). We conclude that PK, like CK, is increased following exercise due to liberation of muscle enzyme. However, only severe exercise is likely to lead to a substantial increase in plasma PK activity and therefore prejudice its clinical usefulness as a diagnostic test.
mesh_terms: D000293:Adolescent; D000328:Adult; D003402:Creatine Kinase / Q000097:blood*; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion; D011770:Pyruvate Kinase / Q000097:blood*; D012420:Running
chemical_list: D007527:Isoenzymes; D011770:Pyruvate Kinase; D003402:Creatine Kinase