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 decrease followed by a slight elevation (in 12% of untrained persons and 41% of athletes); (2) a steady level below the initial value throughout exercise (in 50% of untrained persons and 30% of athletes); (3) an initial increase followed by a slight decrease (in 12% of untrained persons and 7% of athletes); (4) a steady level slightly above the initial value throughout exercise (in 12% of untrained persons and 11% of athletes); and (5) an initial decrease followed by a slight elevation and then by a decline (in 11% of untrained persons and 14% of athletes). The distribution of persons between these variants did not depend on the fitness level. In the case of an initial increase in glucose concentration, a substantial rise in blood somatotropin level was observed during the first 30 minutes of exercise. A lag period in the rise of somatotropin level was common for some of the cases with an initial decrease in glucose concentration. When the initial increase was followed by a decrease in glucose concentration, a diminution in somatotropin concentration began during the second half of the first hour (in other cases it occurred within the second hour of exercise) and was more pronounced than in persons with a different glucose pattern. The highest somatotropin concentration was observed in the case of a steady glucose concentration being maintained initially and throughout exercise. Insulin dynamics were similar in all variants of the blood glucose pattern. During the postexercise recovery period, an elevated insulin concentration was detected in conjunction with a maintained euglycemia. When the postexercise increase of insulin concentration was not found, an augmented glucose level was shown either at the 6th or at the 24th hour after the cessation of exercise.