Physical Training in Human Obesity II. Effects on Plasma Insulin in Glucose-Intolerant Subjects without Marked Hyperinsulinemia

Five severely obese subjects with decreased glucose tolerance but without marked hyperinsulinemia were trained physically, producing a slight circulatory adaptation and an increase in muscle aerobic enzyme activity. The patients ate ad libitum, and no decrease of body fat was found after training. Glucose tolerance did not change. Fasting plasma insulin, as well as the sum of insulin values, decreased after an intravenous glucose tolerance test, but not after a peroral glucose tolerance test. Excretion of 17-ketogenic steroids was unaltered. It was concluded that physical training can cause a decrease in plasma insulin in glucose-intolerant patients without marked hyperinsulinemia, concomitant with minor effects on oxygen transport system, and no effects on body fat, glucose tolerance, enteric insulinogenic factors, and 17-ketogenic steroid excretion.