11/03/2011 08:26 am ET Updated Jan 03, 2012

The Sleep-Weight Connection: Gender Matters

We know that getting a healthy amount of sleep is critical to losing weight. It's also true that maintaining a healthy weight can help you sleep better. A recent study explores the effects of extra weight on sleep, and also examines how gender may play a role in the equation. The study was conducted by Northwestern University's Comprehensive Center on Obesity, and BodyMedia, Inc, which makes armbands that measure an individual's energy expenditure. Researchers were looking for differences between the sleep times of men and women across a range of BMI levels. BMI, remember, is Body Mass Index -- a measurement of body fat based on height and weight.

The study included 6,344 men and women ages 20-60, with BMI from 18-40, which spans the range from underweight to healthy weight, overweight and obese. All of the participants were users of the BodyMedia armband, which in addition to measuring calorie output also collects data from the body that can be used to predict sleep. They wore the device at least 23 hours per day. When measuring sleep, researchers included both nightly sleep and naps.

  • Women slept more than men, by an average of 20 minutes. The average nightly sleep time for women was 6.9 hours, compared to 6.6 hours for men. This was true across the spectrum of BMI levels.
  • For both men and women, there is an overall decrease in sleep as BMI rises.
  • The relationship between sleep and BMI is different for women than for men: researchers found that diminished sleep is more closely linked with higher BMI in women than in men.

Results such as these are yet another compelling piece of evidence of the strong links between sleep and weight. It's a relationship that works in multiple directions: lack of sleep can lead to weight gain, and extra weight can undermine quality and quantity of sleep. And both conditions -- sleep deprivation and unhealthy weight -- are known to elevate the risk for a wide range of health problems, from heart disease and diabetes to depression. It's important to know the differences in the ways men and women experience the relationship between weight and sleep, in order to develop treatments that are targeted and effective. There are some basic habits that can help everyone -- male or female -- maintain a healthy weight and strengthen their sleep:

Exercise. This one's a no brainer. Regular physical activity will help you maintain a healthy weight. It can also improve your sleep. Research has shown that aerobic exercise can improve sleep for people with insomnia. For the most sleep-enhancing exercise routine, get moving in the morning, and get outside in the sunlight. This early-in-the-day exertion and exposure to sunlight will strengthen your circadian rhythms, helping you to feel more alert during the day -- and sleepier at night. If morning exercise doesn't fit in your schedule, find another time during the day that does. To avoid exercise interfering with winding down for sleep at night, schedule your workout no closer than four hours before bedtime.

Drink in moderation. Drinking alcoholic beverages comes with lots of calories, which can undermine an otherwise healthy weight-loss routine. Alcohol is also disruptive to sleep. A couple of glasses of wine may help you fall asleep faster, but in actuality the presence of alcohol your system prevents you from reaching the deepest stages of sleep, which are the most restorative. I'm not saying you have to abstain altogether -- just keep things very moderate. To avoid having even a small amount of alcohol interfere with your sleep, make sure your last drink happens no closer than three hours before bedtime. And try my glass-for-glass strategy: for every alcoholic drink you consume, alternate with a glass of water.

Strive to be consistent. We are creatures of habit. Our bodies respond to routine. Setting regular wake times and sleep times, as well as mealtimes and times for exercise, has been shown to help improve sleep quality, and reduce insomnia rates, particularly in older adults. Another place where routine matters? Bedtime. If you're a parent you know how much a bedtime routine can soothe, relax and prepare your child for bed and sleep. As adults, we're no different! A nightly routine that includes time to wind down, away from television, computers, PDAs and the like, will help your body and mind relax and prepare for sleep.

Keeping your weight healthy and your sleep habits strong often isn't about a handful of big decisions, but rather a whole series of small ones, made day after day. Why not start today?

Sweet Dreams,
Michael J. Breus, PhD
The Sleep Doctor™

"The Sleep Doctor's Diet Plan: Lose Weight Through Better Sleep"

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Twitter: @thesleepdoctor