Getting less than 7 hours of sleep a night? Beware. Lack of sleep is associated with extra pounds.
We need a full night's sleep for good reasons. It helps us stay alert. It helps our bodies function properly.
There's also evidence from several studies that lack of sleep can upset hormone levels, which could cause you to gain weight.
And being overweight raises your risk for many diseases, including diabetes and heart disease.
Unfortunately, studies haven't made it clear if poor sleep packs on the pounds. Or if being overweight makes sleep more difficult.
That's a puzzle scientists are still trying to solve.
Sleep deficit and weight gain
Most people would probably guess that those who sleep more also weigh more. It makes sense, right? Sleeping doesn't burn many calories, so people who sleep a lot should use less energy and be heavier.
But research has shown the opposite. The less you sleep, the more you weigh.
Some studies have found that when it comes to sleep and extra weight, men and women differ. But the results haven't been consistent. In some cases, women seemed more affected by lack of sleep. In other studies, men did.
Compared to staying at a stable weight, gaining 10 pounds can double your risk of diabetes. Other studies have associated short sleep with a greater risk of diabetes and heart disease.
How sleep affects weight
There is evidence that poor sleep causes weight gain. Researchers have found that sleep cycles are closely tied to hormones that affect appetite, energy and metabolism. In particular, people who are sleep-deprived tend to have lower levels of leptin and higher levels of ghrelin. Leptin is a hormone that tells your brain when you are full. Ghrelin is sometimes called the "hunger hormone" because it increases appetite.
Disturbed levels of leptin and ghrelin may help explain why skipping sleep can pack on pounds. A high ghrelin level may make us feel hungry. If leptin is low, we may not feel full even when we are. That makes us more likely to overeat.
On the other hand, there's also evidence that being overweight interferes with getting a good night's sleep. Obesity is strongly associated with sleep apnea and irregular breathing.
Whether lack of sleep causes weight gain or the other way around, it pays health dividends to get a good night's rest. If you have trouble getting enough sleep, try these tips:
- Go to bed and wake up at the same time every day, including weekends.
- Make sure your bedroom is dark, quiet and cool. Use a sleeping mask and earplugs if you need to.
- Exercise regularly, but finish your workout at least three hours before bedtime.
- Avoid caffeine (if you are sensitive to it) and alcohol (if you choose to drink at all) for four to six hours before you go to bed.
- Don't eat a heavy meal or drink a lot of liquids close to bedtime.
Greg Breining contributed to this report.
Created on 08/02/2005
Updated on 12/19/2012
- National Heart, Lung and Blood Institute. Your guide to healthy sleep.
- Motivala SJ, Tomiyama AJ, Ziegler M, Khandrika S, Irwin MR. Nocturnal levels of ghrelin and leptin and sleep in chronic insomnia. Psychoneuroendocrinology. 2009;34(4):540-545.
- National Sleep Foundation. Obesity and sleep.