Six to Seven Hours of Sleep: More or Less Than That Increases Risk of Heart Diseases

A study presented during the 70th Annual Scientific Session of the American College of Cardiology showed that sleeping too much or too little at night could increase the chances of dying from a heart attack or stroke.

Researchers said that this study is the first to explore the link between cardiovascular risk and duration of sleep. This adds to the growing evidence that getting enough sleep plays a significant role in heart health along with diet, smoking, and exercise.

"Sleep is often overlooked as something that may play a role in cardiovascular disease, and it may be among the most cost-effective ways to lower cardiovascular risk," said Dr. Kartik Gupta, a resident doctor at Henry Ford Hospital's Division of Internal Medicine and lead author of the study.

Their findings suggest that sleeping six to seven hours a night is associated with more favorable cardiovascular health than getting more or less than that amount, Science Daily reported.

Assessing ASCVD Risk Based on Sleep Duration

Gupta and his team used data from 14,079 participants during the 2005-2010 National Health and Nutrition Examination Survey, wherein participants were monitored for seven and a half years to know if they died due to heart attack, heart failure, or stroke.

They divided the participants into three groups based on their answers to the surveys about their average sleep duration, which is seven hours.

Then, they assessed the atherosclerotic cardiovascular disease (ASCVD) risk scores, which account for age, gender, race, blood pressure, and cholesterol. They also evaluated the C-reactive protein (CRP), which is a key inflammatory marker linked to heart disease.

The ASCVD risk score is widely used to predict how likely someone is going to have a heart attack or stroke or die from atherosclerosis in the next decade. An ASCVD risk score of less than 5% is considered low risk.

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Too Much or Too Little Sleep Increases ASCVD Risk Score

The median ASCVD risk score is 3.5% among all the participants, pointing to those who sleep six to seven hours a night had the lowest risk, the science news website reported.

While the median 10-year ASCVD score to those who sleep less than six hours is 4.6%, while those who sleep between six to seven hours is 3.3%, and those who sleep more than seven hours is 3.3%.

Gupta said that sleeping less than six hours or more than seven hours every night increases the chances of dying of heart diseases. However, she noted that those who sleep between six to seven hours and those who sleep over seven hours have the same ASCVD risk score.

Moreover, they found that CRP was also higher in participants who are sleeping too much or too little. High ASCVD risk scores in these groups are driven by heightened inflammation as measured by CRP. Gupta added that the effect to the body of having too much or too little sleep could take time for the damage to happen.

Researchers noted that sleeping habits could be changed and improved unlike other risk factors for heart disease, like age or genetics. It can be adjusted to have better heart health.