People who sleep more than 9 hours a night don’t seem to have a higher chance of heart problems or dying from heart issues than those who sleep 7 to 9 hours, at least based on how their sleep was tracked with a wrist device.

People who sleep less than 7 hours a night are more likely to develop heart problems or die from them compared to those who sleep 7 to 9 hours, based on wearable device data.

Getting between 7 and 9 hours of sleep each night seems to be the sweet spot for lowering your risk of heart problems — sleeping less or more than that might raise your risk.

People who sleep 5 hours or less each night are more likely to die sooner from any cause or from heart problems than those who sleep 7 to 8 hours, according to sleep measurements taken in labs.

People in this group who say they sleep 9 hours or more each night are nearly four times more likely to die from any cause than those who sleep 6 to 9 hours, even when you account for heart problems and sleep apnea.

Sleeping more than 9 hours a night doesn’t make your heart healthier—once you’re getting 7 to 8 hours, sleeping longer won’t lower your risk of heart disease.