Heart Disease

Sleep Soundly for Heart Health

Getting a good night's sleep does far more than improve your mood and level of alertness the next day. New research shows that sleep may be good for your heart health as well. That means that, along with maintaining a healthy diet and exercising, adequate sleep should be considered a crucial part of a healthy lifestyle.

About one-third of Americans sleep 6.5 hours or less a night, according to the National Sleep Foundation. While these Americans may be putting their health at risk, people shouldn't spend all of their time sleeping, either; research shows that sleeping more than nine hours may also have deleterious effects, although the reasons for this are less clear. Below, sleep researcher David White, MD, an associate professor of medicine at Harvard Medical School, discusses the complex relationship between sleep and heart disease.

Does sleep affect risk for heart disease?
There is some early evolving evidence that how much you sleep may contribute to heart attacks. We looked a group of 70,000 nurses that had been followed for a long period of time, and we compared how many hours they reported sleeping at night with the number of heart attacks that occurred after they had reported to us how long they slept.

We followed them for about 10 years, and what we found was that if they slept less than six or seven hours per night, the incidence of heart attacks went up relatively steeply. People who slept about five hours a night had about a 40 percent higher rate of heart attack than people who slept eight hours a night. Surprisingly, people who slept nine or more hours also had more heart attacks, though there was not as big an effect. Now this doesn't explain why sleeping less or sleeping more caused the problem, but it certainly suggests that there is an important relationship there.

How might sleep deprivation increase risk for heart disease?
I think there are two or three things that may be important. Short-term studies show that with sleep deprivation, the sympathetic nervous system becomes activated. As a result, your blood vessels constrict and your blood pressure tends to go up. And we think that may play a role in heart disease.

Sleep deprivation probably also affects the regulation of blood sugar. If you're sleep deprived, it requires more insulin to keep your blood sugar where it should be than it does if you're not sleep deprived. And elevated insulin levels and poor blood sugar regulation are major contributors to development of vascular disease, which then can lead to heart disease.

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