A study has found that the circadian or body clock that controls sleep affects men and women in different ways.
According to the research published in the Proceedings of the National Academy of Sciences, the body clock affects sleep and alertness differently in the sexes, and women’s biological clock for sleep is between 1.7 and 2.3 hours ahead of men’s.
Led by Dr. Diane Boivin from McGill University’s Department of Psychiatry and director Douglas Mental Health University Institute, the researchers monitored a group of 15 men and 11 women for 72 hours to observe their body clocks and analyse their natural sleep patterns.
Eight of the women were observed at two different points during their menstrual cycles. Over three days the participants were placed in a controlled environment and kept awake for an hour before being allowed to nap for an hour.
In addition to observing how long it took for volunteers to fall asleep, researchers also monitored their alertness when awake, how they responded to sleep cues over a biological day cycle, body temperatures and melatonin levels.
The results indicate that women are 50 per cent more likely to have troubles sleeping than men and that insomnia also affects men and women in differently.
Boivin explains: “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.”
“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.”
“This observed difference between the sexes is essential for understanding why women are more prone to disturbed sleep than men.”