The temporal relationship between growth hormone and slow wave sleep is weaker after menopause.

Objective: To study the temporal association between growth hormone (GH) and slow wave sleep (SWS) in middle-aged women.

Methods: Seventeen premenopausal and 18 postmenopausal women were studied using all-night polygraphic sleep recordings and blood sampling at 20-min intervals. The postmenopausal women were re-studied after six months on hormone therapy (HT) according to a randomized, double-blind, placebo-controlled protocol.

Results: The total sleep time (premenopausal 361.9±81.5 min, postmenopausal 358±67.7 min) and the percentages of the sleep stages did not differ between pre- and postmenopausal women. In postmenopausal women the first GH peak after sleep onset occurred later and with a more variable time interval compared to premenopausal women. The percentage of SWS was highest 40-20 min prior to the first GH peak after sleep onset in both groups with a higher SWS proportion in premenopausal women (p=0.048), although the total SWS percent for night did not differ. HT did not affect the distribution of SWS in postmenopausal women.

Conclusions: The temporal relationship between GH and SWS in premenopausal women is less robust after menopause and is not improved with HT.