People who sleep more may be at greater risk of developing high blood pressure and stroke.
A new study which looked at the sleep patterns of 360,000 Britons showed that too much sleep is harmful.
Scientists at the Central South University of Xiangya Hospital in China found that participants who slept during the day were about 24% more likely to have had a stroke and 12% to have high blood pressure.
In this research, daytime sleep duration was recorded.
Young people also had an increased health risk from sleeping too much. The study found that those under 60 who slept during the day had a 20 per cent higher risk of developing high blood pressure, while the figure was 10 per cent for those over 60.
"This study echoes other findings that generally show that too much sleep appears to reflect an increased risk for heart health problems and other diseases. "Poor nighttime sleep is associated with poorer health, and napping isn't enough to make up for it," said Michael Grandner of the American Heart Association, who was not part of the study.