Taking lengthy naps every day could reduce your lifespan, a study suggests.
According to scientists, taking an hour-long kip in the day may increase your risk of early death or heart disease by a third.
So academics from China's Guangzhou Medical University recommend having shorter siestas to recharge instead.
Researchers looked at 20 studies that tracked 313,651 people, their sleep patterns, health and deaths.
Of these participants, four in 10 revealed they napped regularly.
Those whose daytime kips lasted more than an hour were 30% more likely to die prematurely.
As well as this, participants who napped for more than an hour a day were 34% more likely to develop heart disease compared to those who never have siestas.
The study data suggests women may be at more risk.
Data showed female participants were 22% more likely to die young if their daytime kips lasted longer than an hour.
Dr Zhe Pan, study author, said: “Daytime napping is common all over the world and is generally considered a healthy habit.
“A common view is napping improves performance and counteracts the negative consequences of "sleep debt". Our study challenges these widely held opinions.
“If you want to take a siesta, our study indicates it's safest to keep it under an hour.
“For those of us not in the habit of a daytime slumber, there is no convincing evidence to start.”
While Dr Pan doesn’t recommend long naps to everyone, he believes it can help those who are sleep deprived.
According to the study, those who slept for less than six hours a night didn’t see their heart disease or early death risk rise after regular afternoon naps.
The scientist added: “The results suggest that shorter naps – especially those less than 30 to 45 minutes – might improve heart health in people who sleep insufficiently at night.”
While the academics explored some interesting possibilities, more research into napping and its impacts needs to be carried out.
Professor Jeremy Pearson, who works for the British Heart Foundation and wasn’t involved with the study, said work needs to be done to explore why napping can have a negative impact.
He said: “Whether sneaking in a daytime nap is good or bad for your heart has been under debate for some time.
“Although this study suggests that daily naps of more than 60 minutes increase the risk of heart and circulatory diseases, more research is needed to understand why.
“Rather than focusing on one factor, it’s important to consider a range of lifestyle choices to keep your heart and blood vessels healthy.
“Doing 150 minutes of moderate exercise a week and eating a healthy Mediterranean-based diet can reduce your risk of having a heart attack or stroke.
“Taking medication to treat high blood pressure and managing your cholesterol can also reduce your risk of life-threatening heart and circulatory diseases.”