Variability in blood glucose change during a 2‐hour exercise

Abstract

To compare individual peculiarities in hormone responses and glucose pattern during prolonged exercise, 34 untrained persons and 27 endurance athletes performed a 2‐hour exercise test on a bicycle with an ergometer at the level of 60% maximal oxygen uptake (VO2max). Serial blood samples were taken through a venous catheter before exercise, at 10, 26, 30, 60, and 120 minutes of exercise and 1,6, and 24 hours after the cessation of exercise. Serum glucose, corticotropin, cortisol, somatotropin, and insulin concentrations were determined. In 79% of cases a slight initial decrease of 0.7 ± 0.23 mM in untrained and of 0.6 ± 0.31 mM in trained subjects was observed in the blood glucose concentration. In half of these subjects an increase over the initial concentration followed after 30 to 60 minutes of exercise. Despite the stable euglycemic level of the mean concentration during the succeeding stages of exercise, individual analysis indicated the existence of five variant glucose patterns: (1) an initial decre...