Study: Sleep Duration May Determine Heart Risk

Only about one-third of Americans get eight hours of sleep each night, and 31 percent report six or fewer hours of sleep each night, according to the National Sleep Foundation.

And that lack of sleep is taking a toll on your heart, according to a new study that found women who get too little or too much sleep have a slightly increased risk of having a heart attack.

Researchers from Brigham and Women's Hospital in Boston studied the link between reported sleep duration and the incidence of major coronary heart disease among 121,700 women enrolled in the Nurses' Health Study. They then tracked the women over a 10-year period.

They found that women who reported five or fewer hours of sleep each night had a 45 percent higher risk of heart disease than women who slept eight hours a night.

Women who slept six hours a night had a 18 percent higher risk, and those who slept seven hours a night had a 9 percent higher risk, according to the study, which is published in this week's Archive of Internal Medicine.

However, getting too much sleep doesn't protect your heart, the researchers found. Women who reported sleeping nine hours or more each night had a 38 percent higher risk of heart disease than those who kept it at eight hours.

The researchers suggested that enough sleep may be nearly as important to heart health as eating right and exercising. Although the study was in women, the researchers suspect the risk exists in men, too.

The researchers, led by Dr. Najib Ayas, said that further studies must be conducted to better understand the link between sleep duration and heart disease risk.