The Right Number for Slumber

Fifty years ago, most Americans got eight to nine hours of sleep a night. Now we average seven hours, and many people get by on just five or six. But recent studies show that skimping on sleep can be harmful to your health.

Researchers at Columbia University found that adults who sleep for less than six hours a night are twice as likely to have high blood pressure as people who get more sleep. Too little sleep also contributes to weight problems by disrupting the hormones that regulate appetite. And less than one week of chronic sleep loss leads to changes in how the body handles glucose and insulin, changes that increase the risk for insulin resistance and diabetes.

How much sleep you need depends on many factors, including age, according to the National Institute of Neurological Disorders and Stroke (NINDS). In general, adults need seven to eight hours of sleep a night. Teens need nine hours, and infants about 16 hours. As you get older, you may sleep more lightly and for a shorter span, although your sleep need doesn't change much from what it was when you were younger.

The amount of sleep you need also goes up if you miss getting enough rest for a few days. Getting too little sleep creates what the NINDS calls a "sleep debt," which eventually must be repaid.

To get the rest you need, try to get between seven and eight hours of sleep every night. If you have trouble falling asleep, try these tips:

• Go to bed and get up at the same time every day, even on weekends.

• Keep your bedroom quiet and dark. Wear a sleep mask and earplugs, if needed.

• Limit caffeine and alcohol, especially close to bedtime.

• Get regular exercise, but not in the hours before bedtime.