The scary health condition sleeping too long can signal

There’s nothing better than sleeping in, right? But sleeping for too long might be signaling something serious about your brain health, researchers from Boston University School of Medicine suggest.

In the study, people who slept for more than 9 hours a night were twice as likely to develop dementia of any kind over a 10-year follow up than those who snoozed between 6 to 9 hours nightly. They were also 71 percent more likely to develop Alzheimer’s disease.

And transitioning to longer sleep was even more telling: People who slept less than 9 hours previously, but changed to more than 9 hours over a 13-year period were about 2.5 times as likely to develop any kind of dementia than those who continually slept more than 9 hours. (Find out what it’s like to have dementia before age 60, from 5 real guys who received the Alzheimer’s diagnosis.)

What’s more, the researchers also discovered that people who slept for a longer duration also had lower brain volumes and poorer processing speeds and functions than those who slept in that 6 to 9 hour sweet spot.

So, what does that mean for your love of sleeping in? Importantly, the researchers believe that trying to make long sleeper snooze for a shorter period of time likely won’t do anything to reduce their risk of dementia. That’s because they think that sleeping long is more so a marker of the degeneration in your brain’s neurons that is linked to dementia—not that long sleep is somehow causing the brain changes associated with dementia.