Before you roll over and hit the snooze button, consider this. A new study by researchers in China has found that people who sleep for nine hours or more each night or excessively nap may have a higher risk of stroke.

The study examined more than 31,000 men and women with an average age of 62 over six years, following their sleeping habits and physical examinations.

The researchers found that people who slept nine or more hours each night were 23% more likely to have a stroke compared with people who slept seven or eight hours a night, even when accounting for factors like smoking and high blood pressure. The researchers also found that those who napped for 90 minutes or longer had a 25% higher risk compared with people who napped for 30 minutes. People who both excessively napped and slept for long periods had an 85% increased risk.

The researchers did not provide a reason for the association, but previous studies suggest that people who sleep excessively may have higher cholesterol levels  and increased waist circumferences and likely have a more sedentary lifestyle overall, which all increase the risk of a stroke.

The researchers noted people self-reported their sleeping habits, which means some of the information may be inaccurate. Also, the average age of participants means the findings might only apply to older individuals.

While a good night’s sleep is essential for good health, people who are concerned about their sleeping habits should speak with their physician to ensure there are no underlying medical conditions impacting their sleep routine. And remember, the quality of your sleep is better for your health than the quantity.