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The ABC's of Zzz's: How Sleep Affects You and Your Health

Sleep. We all need it, but as many as 65% of American adults don't near the eight hours a night recommended by sleep experts. While many of us get by on five or six hours of sleep, recent research suggests chronic sleep deprivation could cause negative long-term physical effects. Dr. Bernadine Healy answers some common questions about these effects and what people can do to get a good night's rest.

Why aren't many Americans getting enough sleep?

This chronic condition of inadequate sleep goes well beyond treatable sleep disorders like apnea and restless-legs syndrome. Americans are busier than ever with their families and careers. As most parents know, it can be a hectic lifestyle with not enough hours in the day--getting the kids ready for school, driving them to school, then going to work, or working into the wee hours. Some are also surfing the net or watching TV late at night. Some may even choose to go supermarket shopping at 3am just to get it done.

How Much Is Enough

How much sleep do people need?

It depends on what age group you fall into.

Common sleep recommendations are as follows:

Toddlers11 hours + 1-2 hours of naps
Preschoolers11-12 hours, with or without a nap
School-age kids10 hours per night
Teens9 hours
Adults8 hours

For toddlers, experts recommend at least 11 hours plus one to two hours of naps per day. Preschoolers should get between 11 and 12 hours, with or without a nap. For school-age kids, an average of 10 hours per night, but needs vary by up to one hour per child. Teens should get about nine hours, and adults should get eight hours a night.

Physical Effects

What are some of the negative long-term physical effects that can happen from not getting enough sleep?

Diabetes: Studies suggest sleep deprivation may increase the risk of diabetes. A study of healthy young men found that without sleep, the central nervous system became more active which blocked the pancreas from producing adequate insulin--the hormone need to digest glucose. After one week, researchers found these men in a pre-diabetic state.

Obesity: Sleep loss may also be partly involved in the epidemic of obesity. One link is the growth hormone that controls the body's proportions of fat and muscle, helping to keep love handles and flaccid muscles at bay. Lack of sleep at a younger age could drive down growth hormone prematurely, accelerating the paunch process. Sleep dprivation could also affect the hormone leptin, which tells the body when it should feel full. When leptin levels drop, the body craves carbohydrates even though you might have had enough calories.

Weakened Immune System: Studies also show that inadequate sleep changes white blood cell counts and immune response modifiers, biological evidence that the body is having trouble fighting infection.

Increased Cancer Risk: There's some evidence of a connection between breast cancer and hormone cycles disrupted by late-night light. Also, melatonin, a substance in the body that is primarily secreted at night, may trigger a reduction in the body's production of estrogen. Light interferes with melatonin release, allowing estrogen levels to rise. Estrogen is known to promote the growth of breast cancers.

Fuzzy Thinking: People who don't get enough sleep generally score lower on tests of judgment and response time than those who had ight hours of sleep. The National Sleep Foundation attributes about 100,000 car crashes a year to sleep deprivation.

Long-Term Memory: Scientists believe sleep is critical for the maintenance and storage of long-term memories. Many think memories are stored during a phase of sleep known as rapid eye movement or REM sleep.

How can you tell if you're sleep deprived?

One easy way to tell is if you can lie down in the middle of the day and fall asleep within 10 minutes, you have short-changed yourself on sleep the night before.

Can you make up sleep that is lost?

Some experts believe that most sleep-deprived people who get more than 8 hours two nights in a row will be reasonably caught up. Catching up is basic arithmetic. For every hour, or fraction, under eight, you need an equal amount of time asleep soon after. But if you're hundreds of hours in debt, you may never pay it all off.

What are some things we can do to get a good night's sleep?

Obviously, you'll want to lighten your schedule and plan to get to eight hours of sleep. If you're having trouble falling asleep, stay away from caffeine, alcohol and overly stimulating or violent television before bed. Troubling reading, exercise and bright lights can also keep you up. If you're hungry, keep your snack small and avoid chocolate, which contains caffeine and fatty foods that can be difficult to digest. A glass of warm milk before bedtime may also be helpful.

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