Hormone fluctuations disrupt sleep of perimenopausal women

June 16, 2015

Science Daily/Endocrine Society

Women in the early phases of menopause are more likely to have trouble sleeping during certain points in the menstrual cycle, according to a new study. During perimenopause -- the earliest stage of the menopausal transition -- women may have irregular menstrual cycles due to the body's fluctuating hormone levels. Symptoms such as sleep disturbances and hot flashes typically begin three to five years prior to the onset of menopause, when a woman is in her 40s.

During perimenopause -- the earliest stage of the menopausal transition -- women may have irregular menstrual cycles due to the body's fluctuating hormone levels. Symptoms such as sleep disturbances and hot flashes typically begin three to five years prior to the onset of menopause, when a woman is in her 40s, according to the Hormone Health Network.

The study examined how hormone fluctuations affected sleep during the luteal and follicular phases of the menstrual cycle. The luteal phase occurs prior to menstruation. The follicular phase refers to the two weeks after menstruation.

"We found that perimenopausal women experience more sleep disturbances prior to menstruation during the luteal phase than they did during the phase after menstruation," said one of the study's authors, Fiona C. Baker, PhD, of the Center for Health Sciences at SRI International in Menlo Park, CA, and the University of the Witwatersrand in Johannesburg, South Africa. "Measures of electrical brain activity found that the hormone progesterone influences sleep, even at this late reproductive stage in perimenopausal women."

The laboratory study examined sleep patterns in 20 perimenopausal women. Eleven of the participants experienced difficulty sleeping at least three times a week for at least a month, beginning with the onset of the menopausal transition.

The women each slept in a sleep laboratory twice -- once in the days leading up to the start of the menstrual period and the other time several days after the menstrual period. Researchers used an electroencephalogram (EEG) to assess the women's sleep and brain activity. Each participant also completed a survey regarding their sleep quality in the month prior to the laboratory testing and underwent a blood test to measure changes in hormone levels.

Researchers found women had a lower percentage of deep, or slow-wave, sleep in the days before the onset of their menstrual periods, when their progesterone levels were higher. The women also woke up more often and had more arousals -- brief interruptions in sleep lasting 3 to 15 seconds -- than they did in the days after their menstrual periods. In contrast, sleep tends to be stable throughout the menstrual cycle in younger women.

"Menstrual cycle variation in hormones is one piece in the overall picture of sleep quality in midlife women," Baker said. "This research can lead to a better understanding of the mechanisms behind sleep disturbances during the approach to menopause and can inform the development of better symptom management strategies."

http://www.sciencedaily.com/releases/2015/06/150616131534.htm

Could quality of sleep have to do with sex differences?

September 12, 2016
Science Daily/McGill University
You may have noticed that women are more prone to sleep disturbances than men. They are, for instance, up to twice as likely to suffer from insomnia than men. Could there be a link between the body clock that regulates sleep and being a female or a male? Yes, according to a new study.

By controlling for the menstrual cycle and hormonal contraceptive use, Dr. Boivin shows, in the Proceedings of the National Academy of Sciences (PNAS), that the body clock affects sleep and alertness differently in men and women.

"For a similar sleep schedule, we find that women's body clock causes them to fall asleep and wake up earlier than men. The reason is simple: their body clock is shifted to a more easterly time zone," says the Director of the Centre for Study and Treatment of Circadian Rhythms at the Douglas Institute, one of the research centres of the CIUSSS de l'Ouest-de-l'Île-de-Montréal.

And, she adds, "This observed difference between the sexes is essential for understanding why women are more prone to disturbed sleep than men."

A novel experiment

In this study, the medical researcher's team compared in 15 men and 11 women variations in sleep and alertness regulated by the body clock. The women who were recruited were cycling naturally and were studied during two phases of their menstrual cycle. This is a crucial point because previous research by Dr. Boivin had shown that the phase of the menstrual cycle affects the biological rhythms of body temperature and sleep.

"Our participants did not exhibit any sleep problems during the study. Just the same, our results are helping us understand, among other things, why women are more likely than men to wake up earlier in the morning and feel tired after a night's sleep. As well, women are less alert at night than men," explains Boivin.

Thus, the results of this study hint that women could be less biologically suited for night work. Further research will be necessary to explore this matter and develop interventions suited to men's and women's health.

More than a third of the Canadian population experiences sleep disturbances. One consequence of this is that close to 15% of adults have functional problems.

https://www.sciencedaily.com/releases/2016/09/160912161058.htm