Physical training in human hyperplastic obesity. IV. Effects on the hormonal status.
Severly obese subjects and sex- and age-matched controls underwnet physical training during a 6-wk period. Evidence of training was shown in all subjects by increased aerobic power. Before training the obese subjects were characterized by the following abberations: decreased glucose tolerance, hyperinsulinemia, elevated blood glycerol and plasma free fatty acids, and a blunted plasma growth hormone response during glucose tolerance. Noradrenaline output was elevated, a finding of potential interest for the explanation of increased lipolysis, blood pressure, and heart size in obesity. With training the following changes were found:In the controls there was evidence for the beginning of a decrease of adipose tissue mass. In the obese, however, body weight, body fat, or fat cell size did not decrease during training. Plasma insulin decreased, and a corresponding increase of plasma glycerol was seen. Glucose tolerance was not changed, and this, together with decreased plasma insulin, indicated an increase insulin sensitivity of the periphery. Changes in noradrenaline or growth hormone during training could not explain this increased sensitivity. Urinary cortisol output was found to decrease after training in the obese; this might be interpreted as a decrease in cortisol secretion allowing a more effective insulin action on the periphery.