The Sleep Prescription Getting a Good Night's Rest May Help Prevent Heart Disease, Stroke, Obesity A

Skimping on sleep to catch up at work, finish household chores or spend quality time with your family can seem like a way to squeeze a few more hours out of your day.

Instead you might simply be stealing time - from the end of your life.

A growing body of scientific research points to serious consequences for the dark circles under our eyes. Sleep deprivation - even a few hours a night - can make you fatter and more prone to diabetes. It messes up your immune system. It raises your blood pressure and puts you at risk of stroke. It might even lead to certain cancers.

The implications are staggering when you consider the number of Americans craving a cat nap. Roughly 70 million Americans suffer from chronic sleep loss and sleep disorders.

Caffeine and sleeping pills aren't the answer, doctors say, because they can't make up for the important physiological changes our bodies undergo in the Land of Nod.

"What we're starting to realize is if you get sleep deprived, your body will start behaving in abnormal ways," says Dr. Ravi Nemivant, board-certified pulmonologist and sleep specialist at Edward Hospital in Naperville. "Sleep is a necessity of your body, rather than a luxury."

So tonight, plump up your pillow, climb under the covers and sleep your way to good health.

Take this to heart

Lack of sleep can literally break your heart.

Numerous research studies link sleep disorders and sleep deprivation to high blood pressure, stroke and other cardiovascular problems.

One disorder, obstructive sleep apnea, brings with it a 42 percent greater risk of having high blood pressure, a 2000 study in the New England Journal of Medicine found. People with more severe sleep apnea have three times the risk.

Those with sleep apnea never enter a deep sleep no matter how long they spend in bed. That's because soft tissue at the back of the throat blocks the airway during sleep, causing repeated bouts of choking and wakening.

People with apnea are also more likely to have atrial fibrillation, a heart rhythm disorder. They have a significantly higher risk of stroke, probably because apnea leads to narrowing of the arteries, or atherosclerosis.

"Sleep apnea occurs in 2 percent to 5 percent of the U.S. population. But if you look at stroke survivors, about 75 percent of them have obstructive sleep apnea," said Dr. Jose Biller, chair of the neurology department at Loyola University Health System in Maywood.

During a sleep apnea bout, the choking sensation triggers a release of adrenaline and the stress hormone cortisol. Blood pressure and heart rate go up. The level of oxygen in the blood drops.

Each episode might last only 10 seconds, but the repetition - sometimes dozens of times an hour - takes its toll on the body. Eventually the blood vessels change structure and thicken, and blood pressure becomes elevated even during the daytime.

Even if you don't have diagnosed sleep apnea, you're not off the hook. An estimated 90 percent of apnea sufferers are undiagnosed. Researchers also have recorded elevated blood pressure - a major risk factor for stroke and heart disease - in people with garden- variety sleep deprivation.

The evidence linking sleep disorders and heart disease is strong enough that cardiologists now routinely question patients about whether they snore and if they feel tired during the day.

"Ten years ago, we didn't ask anything about sleep," said Dr. Mark Goodwin, a cardiologist with Midwest Heart Specialists. "Now even patients ask about it because they've read about sleep apnea."

If you already have heart disease, sleep apnea can aggravate the condition, Goodwin said. The good news is that it works in reverse, too. Patients treated for apnea so they get more sleep often see their blood pressure drop.

Plus, they don't feel so tired.

"A large percentage of patients will actually comment on how much better they feel," Goodwin said. "If we just treat your blood pressure, most of the time you don't know it."

Snack attack

The midnight munchies are no coincidence.

According to research at the University of Chicago, chronic sleep deprivation alters the hormones that drive your appetite. If you don't sleep, you'll start to crave desserts, salty snacks and starchy foods like bread and pasta. Keep it up, and you're courting obesity, with all of its related health problems.

In one study, healthy young men who slept only four hours a night for two nights had a 28 percent increase in the hunger hormone ghrelin. Meanwhile, levels of leptin, which tells the brain your belly is full, dropped 18 percent.

They also craved high-carb foods, rather than more nutritious fare like fruits and veggies.

"When they were sleep-deprived, the low leptin levels were signaling to the brain that more food was needed when in fact the calorie needs were met," said sleep researcher Eve Van Cauter of the University of Chicago. "Leptin was signaling a famine in the midst of plenty."

More research is needed to determine what causes the hormones to fluctuate that way, but it's likely a survival instinct, Van Cauter said.

Most animals skip sleep only if they need more time to find food. Studies of rats and dogs show that the brain regions regulating food intake become overactive when they're sleep deprived.

Studies elsewhere have correlated weight and sleep times. A study of 1,000 people at Eastern Virginia Medical School in Norfolk found that total sleep time decreased as body mass index went up. In general, the fatter folks slept about 1.8 hours less that those with normal weights.

It doesn't take much to make a difference. Researchers found an extra 20 minutes of sleep was associated with a lower body mass index.

Skipping sleep can put you at risk of diabetes by increasing the amount of insulin your body needs to regulate blood glucose levels. In her research, Van Cauter found higher insulin resistance in volunteers who skip just two hours of sleep a night for a couple of weeks.

In fact, skipping sleep had the same effect on insulin resistance as aging.

Whether America's sleepiness is causing the increase in obesity and diabetes is uncertain. Other factors include the easy availability of high-calorie food and busy lives that make us disinclined to exercise.

But if you're tired, you're less likely to head to the gym after work or take time to cook a healthy meal, Van Cauter said. And your sleep-altered hormones will make those super-sized portions available at the drive-through window all the more appealing.

Sick and tired

When you're sick, your best ally for a quick recovery might be your pillow. Well-rested people more easily fight off assaults on the immune system ranging from colds to cancer, recent research has shown.

A 2002 study in the Journal of the American Medical Association showed healthy volunteers' immune system produced fewer antibodies to an influenza vaccine if they were sleep deprived.

Other researchers found similar results after a hepatitis B immunization.

Van Cauter, who measured the flu shot response in sleepy volunteers, said the message is pretty clear: "Get a few nights of good sleep before you get your shots to fully enjoy the benefits."

It's well known that people are more likely to get colds if they're under stress, while studying for medical exams or caring for a relative with Alzheimer's disease, for instance. Those studies suggest that stress impairs the immune system, but it could also be the fact people didn't get adequate sleep, Van Cauter said.

Even cancer is linked to poor sleep.

Night-shift workers, for instance, have higher rates of breast cancer. Doctors say more research is needed to find out exactly why, but sleep deprivation might play a role.

When you're low on sleep, the T lymphocytes that direct an immune response and the natural killer cells that wipe out infections become less effective. Lack of sleep could also impair the body's ability to search out precancerous cells.

"Maybe one of the long-term effects of chronic sleep deprivation is your immune system can't survey your body as well, and you may be at risk for a cancer," Nemivant said.

In Italy, doctors report that cancer patients who receive high doses of the sleep hormone melatonin survive longer. Exactly why is unclear, but the implications are compelling enough that it triggered a double-blind placebo trial in this country to test using melatonin in cancer patients.

"One of the goals of our study is to see if melatonin helps them sleep through the night effectively," said James Grutsch, a consultant who helped design the study for the Cancer Treatment Centers of America.

Patients with non-small-cell lung cancer at CTCA's Midwestern Regional Medical Center in Zion will be divided into three groups to see whether a morning or evening dose of melatonin produces an effect. The third group will receive a placebo.

Researchers will ask about the patients' quality of life, rest cycle and other factors, but the most interesting question is whether better sleep will result in longer lives.

"There does seem to be some effect, but this is still early science," Grutsch said.

Back to bed

How much sleep you really need depends on the individual. Some people are naturally "short sleepers" and thrive with only four hours a night. Most adults need at least seven hours. Kids need as much as 10 hours.

You can figure out how much you need the next time you go on vacation. After a few days without an alarm clock, your sleep time will stabilize. Use that estimate to adjust your bedtime when you go back to your regular life, Van Cauter advises.

Most of us aren't doing that, however.

Surveys by the University of Chicago's sleep lab found people get nearly two hours less sleep on weeknights than they feel they need. The older you get, the harder it is to repay that debt because sleep tends to become more elusive with age.

"If you have a big sleep debt and you're in midlife or older, you may need the whole week to pay it," van Cauter said.

Skipping sleep will do more than make you cranky and prone to falling asleep at the wheel. Van Cauter has measured dozens of biological markers in her sleep studies, and so far hasn't been able to find anything immune to sleep deficit.

"We didn't measure a single hormone that did not change significantly with short sleep," Van Cauter said. "Not a single one."

GRAPHIC: Do you have a sleep disorder?

If you answer yes to two or more of these statements, talk to your physician about your sleep problem.

- I feel sleepy during the day, even when I get a good night's sleep.

- I get very irritable when I can't sleep.

- I often wake up at night and have trouble getting back to sleep.

- It usually takes me a long time to fall asleep.

- I often wake up very early and can't fall back to sleep.

- I experience an uncomfortable/restless sensation in my legs at night.

- My legs often move or jerk during the night.

- I sometimes wake up gasping for breath.

- My bed partner says my snoring keeps him or her from sleeping.

- I've fallen asleep driving.

Source: American Academy of Sleep Medicine

GRAPHIC: Sleepless kids

Sleep-deprived children act differently than adults who aren't getting enough Zs. Look for these signs your child might have a sleeping problem.

- My child has difficulty going to bed or falling asleep.

- My child is always difficult to wake up in the morning.

- My child is often sleepy during the day.

- My child is often hyperactive and cannot focus during the day.

- My child wakes up at night and has trouble falling back asleep.

- My child snores.

- My child stops breathing, chokes or gasps during sleep.

Source: National Sleep Foundation