Oversleeping could be the sign of an underlying health problem and could lead to a higher risk of having a stroke.

Those who sleep for more than nine hours on a regular basis are said to be at an increased risk compared to those who sleep between six and eight hours according to a new study published in the journal Neurology.

In the study researchers from the University of Cambridge followed 10,000 people between the ages of 42 and 81 for almost a decade and of those people 346 suffered a stroke.

From their research, the team found that those who slept the most were 46 per cent more likely to have a stroke than average sleepers.

The study only shows an association; it's unclear if sleeping in for longer was causing the problems or whether the problems were causing people to sleep in for longer.

We need to understand the reasons behind the link between stress 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.

Kay-Tee Khaw, Cambridge Institute of Public Health

Nevertheless, as Time magazine reports, there have been similar studies in the past linking long sleeping hours with a risk of stroke and the researchers speculate that extra time in bed may be linked to increased inflammation which can lead to cardiovascular problems.