Middle-aged women and their health care providers often point to menopause as the cause of poor sleep. But University of Michigan researchers Jane Lukacs and Nancy Reame say it may be time to stop blaming menopause. In an article in the Journal of Women's Health, Lukacs tested the connection between the hormone estrogen and women's sleep quality. The results suggest menopause isn't to blame. "Estrogen has been blamed for a lot, but that doesn't seem to be what's at work here," she said.
To separate aging effects from menopause, Lukacs and her collaborators studied a group of women aged 20-52, and compared them to age-matched women who had gone through menopause, some of whom were using estrogen therapy. For example, she examined a 47-year-old woman still having regular menstrual cycles and compared her data to a 47-year-old woman who had not had regular cycles for 12 months.
They found total sleep time, time spent awake during the night, and efficiency of sleep time all were worse for older women than younger women, regardless of whether the older women were still having menstrual cycles and regardless of whether they used estrogen therapy. While young women around age 24 slept about seven hours, all women in their 40s, regardless of their estrogen levels or menopause status, got only about six to six-and-a-half hours of sleep.
Further, although many women have taken hormone replacement drugs to try to help their sleep, Lukacs and Reame found that for women who were not having hot flashes, there was little difference in sleep between post-menopausal women who were or were not taking estrogen supplements.
"Our findings fail to support the popular view that estrogen plays an important role in sleep enhancement," the article states. "The use of an estrogen patch or gel for three months did not improve any objective measure of sleep architecture."
The researchers noted that because this study involved an in-hospital, one-night sleep observation, further research examining women's natural sleep patterns in their own homes over multiple nights could give more insight into why women sleep poorly at midlife.
They added that in the future, researchers could build on their study and look for such variants as oxygen saturation to look for sleep apnea, leg muscle movement during sleep, and patterns associated with hot flashes, determined by monitoring skin temperature. Hormone replacement therapy might diminish muscle movement during sleep and calm hot flashes, Lukacs said, which could account for some of the beliefs about estrogen improving sleep.
