Could quality of sleep have to do with sex differences?

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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 an original study conducted by Dr. Diane B. Boivin of McGill University’s Department of Psychiatry and the Douglas Mental Health University Institute.

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. 

This research was funded by the Canadian Institutes of Health Research (CIHR), the Fonds de la recherche du Québec Santé (FRQ-S) and the Institut de Recherche Robert Sauvé en Santé et en Sécurité du Travail.

The article “Diurnal and circadian variation of sleep and alertness in men versus naturally cycling women” was published in PNAS on September 12, 2016. 

DOI : http://www.pnas.org/content/early/2016/09/09/1524484113

About Dr. Diane B. Boivin

Diane B. Boivin (MD, PhD) is a research physician, founder/director of the Centre for Study and Treatment of Circadian Rhythms at the Douglas Mental Health University Institute and Full Professor at McGill University’s Department of Psychiatry. She is internationally recognized for her expertise in human circadian rhythms and their application in problems adapting to atypical work schedules and for the management of risks related to fatigue and jet lag.

About the CIUSSS de l’Ouest-de-l’Île-de-Montréal

The Centre intégré universitaire de santé et de services sociaux (CIUSSS) de l’Ouest-de-l’Île-de-Montréal is made up of the CSSS de l’Ouest-de-l’Île, the CSSS de Dorval-Lachine-LaSalle, St. Mary’s Hospital, St. Anne’s Hospital, Douglas Mental Health University Institute, West Montreal Readaptation Centre, Grace Dart Extended Care Centre, and Batshaw Youth and Family Centres.

The Douglas Mental Health University Institute is a world-class institute affiliated with McGill University and the World Health Organization. It treats people suffering from mental illness and offers them both hope and healing. Its teams of specialists and researchers are constantly increasing scientific knowledge, integrating this knowledge into patient care, and sharing it with the community in order to educate the public and eliminate prejudices surrounding mental health.

Source

Centre intégré universitaire de santé et de services sociaux de l’Ouest-de-l’Île-de-Montréal

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