The temporal relationship between growth hormone and slow wave sleep is weaker after menopause.
Level 2 - randomized trial
Randomized, double-blind, placebo-controlled trial evaluating hormone therapy alongside a comparative physiological study
PubMed 22137103 · doi:10.1016/j.sleep.2011.05.010
What was done
Seventeen premenopausal and 18 postmenopausal women were assessed using all-night polysomnography and blood sampling at 20-minute intervals to evaluate the relationship between slow wave sleep (SWS) and growth hormone (GH) secretion. Postmenopausal women were subsequently re-evaluated after six months of hormone therapy (HT) or placebo according to a randomized, double-blind, placebo-controlled protocol.
What was found
Total sleep time (premenopausal 361.9 ± 81.5 min, postmenopausal 358 ± 67.7 min) and percentages of sleep stages did not differ significantly between groups. Postmenopausal women had their first post-sleep-onset GH peak occur later and with greater timing variability compared to premenopausal women. The percentage of SWS peaked 40–20 min prior to the first GH peak in both groups, with a higher SWS proportion in premenopausal women during this window (p = 0.048), though total whole-night SWS percent did not differ. HT did not affect the distribution of SWS in postmenopausal women.
Why it matters
This study shows that menopause is associated with a disruption in the temporal coupling between deep sleep and nocturnal growth hormone release, which is not restored by hormone therapy.
Limits
Sample size was very small (35 total subjects, 18 postmenopausal). The specific hormone therapy regimen and dose are not reported in the abstract. Sampling at 20-minute intervals offers discrete rather than continuous GH tracking, and clinical endpoints were not measured.
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