To feel better and be better, too, try sleep

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Better Sleep Month

To feel better and be better, too, try sleep
Research links lack of shut-eye to a host of physical ailments

By Dennis Thompson
HealthDay Reporter

(HealthDay News) -- Most everyone knows that a good night's sleep leaves you feeling refreshed, alert and aware, ready to take on the day.

But it also leaves you in better shape to avoid chronic diseases such as diabetes, obesity, cardiovascular disease and depression.

Researchers are learning that sleep is important to maintaining physical health as much as mental health. And shorting yourself on sleep exposes you to illness -- a message sleep experts are especially trying to convey during May, designated as Better Sleep Month.

"Every different physiologic system in the body -- respiratory, cardiovascular, urinary, nervous -- their activities are radically different during sleep," said Dr. Lisa Shives, medical director of Northshore Sleep Medicine in Evanston, Ill. "We may not understand how sleep helps each system, but we know it's very important."

A good night's sleep varies from person to person, but doctors agree that most adults need seven to nine hours of sleep each night, according to the U.S. Centers for Disease Control and Prevention.

But two of every 10 Americans sleep less than six hours a night, according to the 2009 Sleep in America poll conducted by the National Sleep Foundation. The average amount of sleep reported on weekdays was 6 hours 40 minutes.

Much of the scrimping on sleep has to do with the pressures of the modern world, Shives said. Sleep has become a luxury rather than a necessity.

"The number one most common sleep disorder in America is willful sleep deprivation," she said. "People are not valuing sleep. They cut back on it to get more done in their busy lives. Bad choice."

It's a bad choice, because researchers have proven that chronic poor sleep is directly related to how long you'll live, said Dr. Ronald Kramer, a neurologist at the Colorado Sleep Disorders Center in Denver and a spokesman for the American Academy of Sleep Medicine.

"If you're getting under seven hours of sleep a night, your chances of dying are higher than if you're getting seven or eight hours of sleep a night," Kramer said. "Bad sleep is a physical stress that probably has the same chemical consequences as high blood pressure or high cholesterol. Chronic bad sleep is a pro-inflammatory state, and pro-inflammatory states are associated with heart disease, stroke, high blood pressure."

Some specific health findings associated with poor sleep include:

Cardiovascular disease. People with sleep disorders face an increased risk for hypertension, stroke, coronary heart disease and irregular heartbeats, according to the CDC. Blood pressure has been shown to increase with a lack of sleep, and people who sleep more suffer less hardening of the arteries. "Sleep is a time of rest for the cardiovascular system," Shives said.

Diabetes. Poor sleep has been linked to more likely development of type 2 diabetes, the CDC says. Lack of sleep appears to interfere with important chemical processes that govern blood sugar control. "People getting less than seven hours of sleep have higher blood sugar in the morning, which shows you're on your way to being diabetic, if you're not already there," Kramer said.

Obesity. Short sleep duration causes metabolic changes that might be linked to obesity, the CDC says. "People who get too little or fragmented sleep start to gain weight," Shives said. "Their appetite hormones get out of whack." An association has been drawn between a lack of sleep and excess body weight across all age groups, but especially in children. Researchers believe insufficient sleep in growing children may interfere with the hypothalamus, the region of the brain that regulates appetite and the body's expenditure of energy.

Immune response. People who get too little sleep are more apt to contract a cold. They also have a harder time fighting off infections. Shives cited studies in which people were vaccinated for hepatitis A and influenza, then deprived of sleep. "The people who were sleep-deprived couldn't mount an immune defense," she said. "The vaccine had no effect." Because the immune system plays a role in fighting cancer, there is some concern -- as yet unproven -- that chronic sleeplessness could increase a person's cancer risk.

Depression. Sleep and depression have long been tangled together, because people with depression often sleep long hours. However, it has been shown that chronic insomnia drastically increases the risk of a major depression, Shives said. Also, recent research has shown that depressive symptoms decrease once a sleep disorder such as sleep apnea has been effectively treated and normal sleep patterns recur, the CDC says.

Sleep still is not well understood. Kramer said that many findings regarding the benefits of sleep are based on what happens when people are deprived of sleep, rather than through a full medical understanding of the function of sleep.

But in the end, the importance of sleep is a common-sense proposition to sleep researchers.

"It's a highly preserved animal behavior across just about all species, including all primates," Kramer said. "It should take up about a third of our lives, and, therefore, one must conclude it has some direct biological significance beyond making us feel good when we've slept."

"People who think they can get away with six hours are fooling themselves," he said. "You get used to feeling bad, or you can't judge what feels bad anymore."

On the Web

For more on healthy sleep, visit the U.S. National Heart, Lung and Blood Institute at http://www.nhlbi.nih.gov/health/public/sleep/healthy_sleep.htm.