Harvard Heart Letter

Uncovering the connection between sleep and heart health

Research we’re watching

Sleeping either too little or too much has been linked to a higher risk of heart disease. But how much do other interconnected factors — namely, activity levels and body weight — affect this observation?

In an effort to find out, researchers studied nearly 240,000 healthy adults ages 51 to 72 who were part of a nationwide health study. The investigators examined the influence of moderate-to-vigorous physical activity, television viewing, and body mass index on sleep duration and death rates.

During an average of 14 years of follow-up, just over 44,000 people died. Compared with people who slept seven to eight hours per day, those with either shorter or longer snooze times were more likely to die of heart disease. How long a person exercised or was sedentary (inferred by TV-watching time) did not appear to affect the connection between sleep and mortality. But among people who were overweight or obese, sleeping less than seven hours per day was strongly linked to a higher risk of death from heart disease. The study appeared in the Oct. 3, 2017, American Journal of Epidemiology.

Learn more about our
health content.