Ever feel like you're more of a morning person than the men in your life? There may be a biological explanation.
A recent study conducted at Harvard-affiliated Brigham and Women's Hospital found that women have a faster circadian rhythm than men, which may be the reason we wake up earlier and sleep less. Jeanne Duffy, one of the study's authors, told NPR: "What we found was that the cycle length of the biological clock in women was shorter on average than it was in men," with a difference of about six minutes.
Think six minutes can't make a difference? Duffy told NPR listeners to think of it as a watch running six minutes too fast; without being reset, it becomes increasingly divergent from the 24-hour cycle.
The Harvard study, conducted on 157 people who spent up to eight weeks in sleep lab, sans windows or external cues indicating the passage of time, also showed 35 percent (over 1 in 3) women had an intrinsic daily cycle that lasted under 24 hours (a.k.a, they created earlier bedtimes for themselves) compared with 14 percent of men.
The research seems to confirm the results of a 2007 National Sleep Foundation poll, which found that women struggle with a range of sleep issues:
- Two-thirds of women (67 percent) report experiencing any sleep problem at least a few nights a week with 46 percent reporting this occurring every night or almost every night
- About one-half of women say they wake up feeling unrefreshed (50 percent)
- Over one-third of women surveyed say they had difficulty falling asleep (37 percent) and/or woke up too early and couldn't get back to sleep (34 percent) at least a few nights a week.
How big a problem is it for women not to get enough sleep?
If 24 hours never really felt like enough to get everything done, women's internal clocks may give them slightly less time than that, according to the new Harvard study. That may make it even more difficult to set aside time for adequate sleep, but ignoring your body's urge for sleep could do more harm than good. The 2007 Sleep Study found that women who said they only get a good night's sleep a few nights a month or less were more likely to miss at least one day of work because of sleep problems or sleepiness (20 percent vs. 10 percent) and more likely to drive drowsy at least once a month (39 percent vs. 18 percent).
And, for women who say their sleepiness interferes with daily activities at least a few days a week, the risks only mount: They are 36 percent more likely to be classified as obese. The Harvard Women's Health Watch suggests that chronic sleep deprivation may cause women to gain weight by affecting the way we process and store carbohydrates and may impact the hormones that affect appetite. According to the Harvard Women's Health Watch, too little sleep can also ultimately alter immune function, making you more susceptible to disease.
So how do we actually go about spending more time in bed?
- "If your cycle length is shorter than 24 hours, you need evening light to keep you synchronized," Duffy advised NPR listeners. She recommends blackout shades in the bedroom to prevent the morning sun from waking you up early. (And while your at it, consider redecorating: according to the BBC, a relaxing sleep environment without flashing TV screens can go a long way.)
- Not into redecorating? Try sleeping with your significant other. The 2007 Women's Sleep Study found that "Women who sleep with their significant other only (65 percent) are significantly less likely than women who sleep with a pet (76 percent) or with a child or infant (81 percent) to experience symptoms of insomnia at least a few nights a week."
- Exercise regularly. It's been proven to let you rest more deeply at night -- just don't do it right before bedtime, as exercising can stimulate the brain rather than relax it, according to the BBC.
- The Mayo clinic advises creating a nightly bedtime ritual: Doing the same things each night tells your body it's time to relax.
Are you an early bird or do you defy the study results and thrive in the evening? Let us know your bedtime rituals and tricks for getting a good night's sleep by tweeting @HuffPost Women with the hasthtag #SleepSecrets