Getting to the ‘heart’ of sleep
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by Andrew D. Calvin, M.D., Mayo Clinic Health System
Sleep is essential for a healthy heart. People who don’t sleep enough are at higher risk for heart disease. One study that examined data from 3,000 adults over age 45 found that those who slept fewer than six hours per night were about twice as likely to have a stroke or heart attack as people who slept six to eight hours per night. Sleep deprivation is a growing problem, with 28 percent of adults now reporting that they get six or fewer hours of sleep per night.
It’s not clear why less sleep is detrimental to heart health, but researchers understand that sleeping too little causes disruptions in many normal functions of the body, including blood sugar levels and blood pressure.
Lack of sleep also is a “weighty” issue. In a 2012 study I conducted, 17 people ages 18 to 40 spent 15 days in our research lab and were allowed to eat as much as they wanted. Half the group was only allowed to sleep two-thirds of their normal sleep time; the other half served as controls and were allowed the full amount. We found that the test group ate an average of 559 additional calories each day. More importantly, it didn’t seem that the people who were awake longer burned more calories from additional activities. Our study concluded that if that rate of consumption kept going, the people who slept less could gain up to 1 pound a week.
Furthermore, those in the study who slept less had signs that their blood vessels didn’t work as well, something called endothelial dysfunction. We know endothelial dysfunction is found in people at risk for heart attacks, so this is a worrisome finding that should be explored further.
Another condition which can affect heart health is sleep apnea, a condition which causes people to wake frequently throughout the night. This disrupted sleep can lead to higher blood pressure at night and during the day, and may increase the risk for heart attacks and stroke. One study found that over an eight-year period, men with severe sleep apnea were 58 percent more likely to develop congestive heart failure than men without the nighttime breathing disorder. But it doesn’t take a severe underlying sleep disorder to see effects on the heart. Poor sleeping, as a result of changing work schedules or poor sleep habits, for example, can put you at risk, as well.
Don’t compromise your heart health. Do your best to make quality sleep a priority in your life. This isn’t being lazy; it’s good wisdom. The National Sleep Foundation recommends that adults get seven to nine hours of sleep a night.