How are men's and women's sleep cycles different?

We all know that men and women have different sleep tendencies -- think of all those early bird/night owl partnerships out there -- but we’re now beginning to understand more about why gender matters when it comes to sleep. I was particularly interested in a recent study that shows evidence of some fundamental biological differences between men’s and women’s sleep.

In this study, researchers observed the circadian cycles of 157 men and women between the ages of 18 to 74, measuring melatonin levels and body temperature in order to track the 24-hour sleep-wake cycle. Over the course of a monthlong inpatient sleep period, researchers found significant differences between men and women in both the timing of their circadian clocks -- which help govern sleep times and wake times -- and the duration of the circadian clock itself. Among those differences:
  • Women’s circadian clocks are set to an earlier hour than men’s, making them more inclined to fall asleep earlier and also to wake earlier. Women showed a stronger inclination for activity earlier in the day than men.
  • Circadian cycles were actually shorter for women than for men, by six minutes. Even a slight difference can have significant impact on nightly sleep and on energy levels during the day. Think about a clock that runs a handful of minutes behind every day. Over time, those minutes really add up!
  • Not only did women’s circadian clocks generally run earlier and shorter than men’s, but also many more women had internal clocks that ran a full cycle in under 24 hours.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.