Ever noticed how after a late night out with your man, you have a harder time the next day than he does? It's not all in your head. Thanks to different hormonal makeups, we suffer more emotionally and physically when we're short on zzzs. [Tweet this unfair fact!]
"Poor sleep certainly had a more profound effect on women than on men," says Edward Suarez, Ph.D., an associate professor at Duke University School of Medicine and lead researcher of a study that looked at the relationship between poor sleep and poor health. He found that for women, reduced sleep was associated with a significant increase in risk of heart disease and diabetes, as well as more stress, depression, anxiety, and anger. However, these associations were weaker or nonexistent for men.
What gives? Testosterone. Levels of this hormone rise after poor sleep in men, and "because it decreases insulin and increases muscle mass, testosterone has an anti-inflammatory effect, which kept men's stress hormones lower," he explains.
Unfortunately for us, women's hormones, especially progesterone, do not have that same stress-dampening effect. Estrogen is known to have an anti-inflammatory effect, so the decline in the hormone as we get older could contribute both to worse sleep and to feeling even crappier after a night spent tossing and turning.
And while you may have seen recent headlines proclaiming that women need more sleep than men, the truth is a lot more complicated, says Aric Prather, Ph.D., an assistant psychiatry professor at the University of California, San Francisco and author of a larger 2013 study that confirmed Suarez's findings. "I don’t think there is any good evidence yet that women need more sleep than men," Prather says. "The present data is more in support of the fact that women may be more susceptible to the negative effects of poor sleep quality."
In both studies, physiological stress was measured by looking at blood levels of C-reactive protein (CRP), which rises in response to inflammation and is considered a better marker of stress than looking at cortisol levels alone. The volunteers were also asked to rate their sleep quality.
In addition to overall snooze time, Suarez's study looked at four different aspects of "disturbed" sleep: how long it took subjects to fall asleep, how many times they woke in the night, how long it took them to fall asleep again, and if they awoke too early in the morning. Surprisingly, it wasn't just the total number of hours in the sack that made the difference. According to Suarez, the No. 1 factor correlated with an increase in CRP for women was taking more than 30 minutes to fall asleep when they first hit the sheets. This is a double-whammy for women, he says, who not only are we 20 percent more likely to suffer from insomnia than men but also suffer more ill effects from it.
Large epidemiological studies have found that women tend to rate their quality of sleep as worse than men even when their sleep is shown through objective measures to be better. "This raises the question of whether women may be more sensitive to sleep problems, which may have biological consequences, including elevations in inflammation," Suarez says.
Kelly Glazer Baron, Ph.D., clinical psychologist and director of the Behavioral Sleep Program at Northwestern University Feinberg School of Medicine, adds that bad sleep can become a vicious cycle: Shoddy shut-eye boosts stress, which in turn causes insomnia for many people, leading to even more stress on top of what you experience every day.
But there are things women can do to mitigate these effects. "We can improve how we prevent disease over lifetime simply by making small improvements in our sleep," Suarez says. This is why it's important to promptly treat sleep problems, especially insomnia. Baron says that if your insomnia reaches the point where it is making it hard to function during the day, talk to your doctor about lifestyle modifications and other options.
She also recommends establishing a regular fitness routine. "It’s been known for a long time that exercisers sleep better," she says, citing her recent studies showing that 16 weeks of aerobic exercise at moderate intensity four days a week helped women get at least seven hours of sleep a night and also improved their perception of the quality of their rest. [Tweet this tip!]
Finally, don't forget the recommendations from the National Sleep Foundation, Prather says (which you likely can recite in your sleep—or as you stare at the ceiling): Go to bed at the same time every day of the week, avoid heavy meals before bed, establish a relaxing bedtime routine, don't nap, and exercise daily.