Too Much Sleep Can Kill You


By Yvonne Milosevic

Raise your hand if you’ve ever woken up feeling low-energy despite a seemingly long night of sleep.  (Okay, guess that’s about everybody). We hear a lot about overworked executives and the chronic sleep deficit in this country, but people can suffer serious cognitive or health defects from oversleeping.

It seems excessive snoozing carries the same health risks as too little shuteye. We’re talking heart disease, diabetes, obesity and the real bummer—higher mortality risks. Yikes.

Scientists at Keel University in the UK published a study in the Journal of the American Heart Association identifying what they labeled a “J-shaped” connection between the duration of sleep and cardiovascular illness and death.

The J shape, with its sharp upward trajectory, illustrates how these health risks spike in tandem with excessive slumber. According to the researchers, sleeping for nine hours carried a 14% higher risk of death. Ten-hour periods of sleep, meanwhile, carried a 30% higher risk.

They call their findings significant because they highlight a problem with longer as opposed to shorter sleep, and that the greater the duration, the more severe the problem appears to be.

“Our study,” says lead study author Dr. Chun Shing Kwok, “has an important public health impact in that it shows that excessive sleep is a marker of elevated cardiovascular risk.”

And the optimal number of sleep hours is…

So, is there a sleep sweet spot? Neuroscientists at the Brain and Mind Institute at Western University in Canada conducted a massive study to learn more.

“We wanted to find out what sleep is like in the real world,” says Adrian M. Owen, a professor in cognitive neuroscience and imaging. They tracked 44,000 people in real-life conditions and then assessed the volunteers using a variety of cognitive and neurological tests.

Turns out, these Canadian researchers have confirmed what doctors everywhere have recommended for years. Seven to eight hours each night really is the magic number for optimal cognitive performance.

But the real kicker:

“We also found that people who slept more than that amount were equally as impaired as those who slept too little,” noted research associate Conner Wild.

Harvard Medical School researchers make the connection as well between too much sleep and too little energy in their special health report, Boosting Your Energy. In a nutshell, whenever you deviate from your normal sleep patterns, your body rhythms go out of whack and, voila! Say hello to daytime fatigue.

If your #sleepgoals include waking up refreshed and operating your coffeemaker like a boss in the morning, heed the following advice.

“The best solution is to figure out how many hours of sleep are right for you and then stick with it — even on weekends, vacations, and holidays,” say Harvard researchers. Oh, and probably your mom, too.