So it may come as a shock to learn too much sleep could actually be bad for us.
People who normally get more than eight hours of sleep are twice as likely to have as stroke as others – and women are particularly at risk, a Cambridge University study found.
Independent sleep expert Dr Neil Stanley said having long lie-ins could be harmful for those who normally get little sleep. Keeping regular hours is the key, he added.
If we wake feeling sluggish, we have probably slept for too long.
The Cambridge study, which focused on long-term sleep habits, found those who normally get more than eight hours a night are twice as likely as others to have a stroke.
Among those whose went from not sleeping very much to sleeping more than average a few years later, the risk was almost quadrupled.
The researchers said it was not clear whether these people were sleeping in because they were already ill or whether there is something about the extra hours in bed that is bad for us.
Either way, they said, asking apparently healthy people how long they sleep for could be a useful way to spot those at risk of a stroke. They could be closely monitored and given extra help to stop smoking or improve their diet.
A third of the 150,000 Britons who suffer a stroke each year will die and many of those that do survive are left severely disabled, so anything that reduces the risk could have huge benefits.
The nine-year study tracked the health of nearly 10,000 men and women from Norfolk, aged 42 to 81. At the start, they were asked how long they slept on average. The question was then repeated four years later.
During the study, 346 of the men and women had a stroke. Analysis of the results then flagged up a clear link between excessive sleep and ill health.
This link was particularly strong for those over 63 and for women, the journal Neurology reports.Importantly, it could not be explained away by the long-sleepers having other health problems, such as heart disease.
Finally, the researchers looked at the results of previous studies involving more than half a million people from seven countries.
These confirmed the link between sleeping for a long time and suffering a stroke.
Professor Kay-Tee Khaw, the study’s senior author, said: ‘We need to understand the reasons behind the link between sleep and stroke risk. What is happening in the body that causes this link?
‘With further research, we may find that excessive sleep proves to be an early indicator of increased stroke risk, particularly among older people.’
Researcher Yue Leng said: ‘It’s apparent from both our own participants and the wealth of international data that there’s a link between sleeping longer than average and a greater risk of stroke.’
Dr Madina Kara of the Stroke Association said: ‘In the past, oversleeping has been linked to a host of health problems, including diabetes and obesity.
‘The results of this latest research suggest that sleeping for longer could be a sign that you’re at increased risk of stroke, particularly among older people.’
Dr Kara said high blood pressure, smoking and a lack of exercise are all risk factors, adding: ‘Anyone concerned about their health should have a chat with their GP.’
This story was written by Fiona McCrae and first published in The Daily Mail.