The authors suggest the hypothesis that the obesity often associated with sleep apnea syndromes is related to changes in HG secretion. Indeed, as HG secretion is sleep related any disturbances due to apnea during may alter the GH secretion. In order to test their hypothesis the authors studied, during the course of 24-hour polygraphic recordings, the levels of HG, blood glucose and free fatty acids, in 16 subjects, 14 of whom were obese and 9 of whom had the sleep apnea syndrome. The results obtained confirmed the relationship between the number of apnea and the stability of sleep. They also demonstrated a relationship between GH secretion and both the stability of sleep and obesity. These results, therefore, suggest that apnea plays a role in obesity development.