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Next time your boyfriend wants to stay out late on a Friday, tell him you need more beauty sleep than he does – and blame science. According to a new study published in Proceedings of the National Academy of Sciences, women have more trouble managing disturbances in their regular sleep schedule than men do.
In the study, researchers took 18 women and 16 men out of their natural environments. They desynchronized them from a regular 24-hour day, and instead reprogrammed their circadian rhythms to match a 28-hour day with no daylight or time cues to guide them. (You’d see a very similar effect among those who do shift work.)
Every three hours over a 10-day span, researchers took subjective measures from the participants, like sleepiness, effort, mood, while also administering objective tests on attention span, memory and motor control.
The lengthened circadian phase produced stronger effects in the subjective tests than the objective tests; both men and women typically self-reported that they were sleepy, but still scored relatively well on the tests like that of memory, says Nayantara Santhi, PhD, a research fellow at the Surrey Sleep Center at the University of Surrey. “However, when a long time awake coincided with a shifted phase, similar to what happens during night shift, accuracy declined more steeply in women than in men,” she tells Yahoo Beauty.
According to senior study author Derk-Jan Dijk, PhD, Director of the Surrey Sleep Center, scientists have known that sleep changes tend to affect women more profoundly than men. “As early as 1984, human circadian rhythm researcher Rutger Wever reported sex differences in the speed of the human circadian clock, as well as differences in sleep duration when participants were studied under ‘time free’ environments,” he tells Yahoo Beauty. “Since then, several investigators have reported sex differences in the speed of the circadian clock and also in the structure of sleep. Our study focuses on the circadian regulation of waking performance.”
What does this mean for you? S-L-E-E-P. “There are some indications that women need slightly more sleep than men and they certainly have more deep sleep,” says Santhi.
In their paper, the authors note that previous research suggests women are more prone to injury than men while working longer, non-standard shifts. Since women tend to take on more familial responsibilities on their off days (and sleep less) than guys, those findings might be expected – but this new research hints that throwing your circadian rhythms out of whack also leads to changes like sleepiness and moodiness, as well.
Outside the lab, whether you’re a hard-working nurse or you’re crazy jet-lagged after your cross-timezone vacation, make sure to get some extra sleep.