How are sleep and heart disease related?

Studies show that power naps can be good for your heart. See more heart pictures.
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It's been a long day at the office. Your clients are demanding, and you're doing the work of three people. All you can think about at the end of your 14-hour day is falling face first into your California King, four-poster bed. That goose down, full-body pillow and comfort-top mattress are calling your name. There's no TV, no laptop and no telephone to distract you from getting acquainted with your 500 thread count comforter and Egyptian cotton sheets. You pull the shades and strap on your silk aromatherapy sleep mask knowing that all will be repaired by morning.

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A­ good night's slumber will leave you feeling calm, refreshed and ready the next day. Research shows that sleep's also good for your overall health and especially for your heart. The amount of sleep people need varies, but the general consensus is that adults require about eight hours of sleep per night [source: APA]. How much sleep you need also changes as you age. Newborns have a pretty easy gig -- they sleep about 16 to 18 hours a day. At three months, babies begin to recognize day as day and night as night -- what's known as the circadian rhythm. At one year old, babies catch Zs for 10 to 12 hours a night and nap another three to five hours.

­During puberty, kids need more sleep than in their prepubescent period, and their body clocks shift, making it more difficult to fall asleep at night and wake up in the morning. Teens don't start producing sleep hormones until 1 a.m., compared to 10 p.m. in adults. In college, things get a little out of hand. One study reveals that one quarter of all college students are chronically sleep deprived [source: The New York Times]. That's nothing compared to adults. Nearly 60 percent of adults report having sleep problems, and only 37 percent get the recommended eight hours per night [source: National Sleep Foundation]. About half of these sleep problems are stress related. Sometimes the quiet recesses of the bedroom are the only places that allow the mind to focus on the day's events.

It's become clearer in recent years that getting the right amount of sleep not only gives you energy, it's good for your health. Research shows that too little or too much sleep can have some poor effects on your blood pressure and ticker, specifically.

Effects of Sleep Deprivation on the Heart

HowStuffWorks 2008

There's an old joke among doctors that the function of sleep is to cure sleepiness. Despite an abundance of research, we still aren't sure exactly why we sleep. But we know we need to. Recent studies indicate that too much or too little sleep can be a factor in developing heart disease, just like smoking and packing on the pounds.

A 10-year study performed by Harvard University tracked the sleep habits and health of more than 70,000 women between the ages of 45 and 65 that had no previous history of heart disease. In the end, 934 of these women suffered from coronary heart disease and 271 died from it. The researchers accounted for factors like age, weight and whether they smoked, then looked at the subjects' sleep patterns. Five percent of the women slept less than five hours per night. Those women were nearly 40 percent more likely to suffer from heart disease than women who slept an average of eight hours. Women who slept more than nine hours per night were 37 percent more likely to have heart trouble.

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Previous studies have shown similar results for men. Short-term sleep deprivation is known to raise blood pressure and stress hormones, lower glucose tolerance and even lead to irregular heartbeats. All of these factors are precursors to coronary disease. Chronic sleep deprivation promotes weight gain and diabetes, both of which can send you to the emergency room grabbing your chest. Going without enough sleep also affects the functioning of the lining inside the blood vessels and can cause some low-grade inflammation that could lead to heart disease.

Sleep apnea is another problem. This is a condition that makes your airway temporarily collapse when you sleep, forcing you to wake up and resume breathing. This makes for fitful sleep at best. Research has shown that people with sleep apnea also show marked increases in their blood pressure over the years. They also have a higher level of sympathetic nervous system (SNS) action. The SNS controls the heart rate and the constriction of the blood vessels. If you don't have sleep apnea, shortly after you fall asleep, your blood pressure and SNS activity will slowly fall. This can't happen when you're waking up at regular intervals to resume breathing.

If you think you're in the clear because you're a young whipper-snapper, think again. Teens that sleep less than 6.5 hours per night are more than twice as likely to get high blood pressure [source: AHA]. When you consider that teens average roughly seven hours of sleep when they require nine, it's clear that kids need to put down that Guitar Hero axe, shut off the iPhone and catch some Zs.

Now for the good news. If you want to eliminate this factor from whether you develop heart disease, all you need to do is go beddy-bye for eight hours. There are other factors, like what you eat and how much you exercise, but this one is taken care of by doing something most people love to do -- sleep. Doctors even believe that 30-minute naps a few times a week can improve your health, and many forward-thinking companies are outfitting their buildings with nap rooms.

If you have trouble sleeping, make your bedroom a haven for slumber. Paint your walls in cool blues. Ditch the TV and the laptop. Try to sleep eight hours each night -- you're doing your heart a big favor.

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Sources

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  • "Good news for slackers: naps can help the heart." Associated Press. Feb. 13, 2007.http://www.msnbc.msn.com/id/17115245/
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