By Dr. Mallika Marshall, WBZ-TVBy Dr. Mallika Marshall

BOSTON (CBS) – Could getting more than eight hours of sleep a night be a bad thing? Many of us are lucky to get that much, but if we do, Dr. Mallika Marshall says it might be a warning sign for stroke.

The National Sleep Foundation says adults between the ages of 18 and 64 should get seven to nine hours of sleep a night, but a new study from the University of Cambridge looked at more than 9,000 middle-aged and older adults and found that those who slept for more than eight hours a night were 46% more likely to have a stroke over the nine and a half years than people who slept six to eight hours a night.

It may be that sleeping longer at night doesn’t actually cause stroke but instead may be an early warning sign. So this doesn’t mean you should cut back on your sleep but if you tend to snooze a lot at night, your doctor needs to monitor you closely for stroke risk factors like high blood pressure and high cholesterol and keep those conditions in check.

Dr. Mallika Marshall