Is "Too Much Sleep" Really A Thing?

There's a fine line when it comes to the right amount of sleep. Get too little sleep, and you'll be exhausted all day, chugging down coffee. Oversleep, however, and you'll spend the whole day in a lethargic daze, feeling as if you've been dragged out of some sort of sleep spell.

The American Sleep Foundation (ASA) says the average adult should be getting between seven and nine hours of sleep every night (though everyone's personal needs might be different). In theory, any more than that would probably count as too much sleep. But beyond losing more hours in your day, is there really any harm in getting more sleep than recommended?

Well, one study from 2016 suggested that people who sleep over eight hours every night might be at higher risk for dying of coronary heart disease. Another from 2014 found that people who slept for longer periods of time are more likely than those who slept less to have persistent symptoms of depression or anxiety. But Rajkumar Dasgupta, MD, assistant professor of clinical medicine at the University of Southern California's Keck School of Medicine, says that sleeping too much probably isn't the worst problem you can have.

"It’s a hard problem to have in our society, which is very sleep deprived," he says. "For the average adult, it's recommended that they get seven to eight hours, but most people don't even get that."

For one thing, he says, it's hard to say what "too much sleep" really means because it varies from person to person. Children from ages six to 12, for example, need nine to twelve hours, and teens need about eight to ten hours.

"Sleep is a complex puzzle and every tip we give for good sleep, it has to be your missing puzzle piece for it to work," Dr. Dasgupta says.

In that sense, he says that he usually determines a healthy amount of sleep by how you get through your day — how much you can do what you need to at work and in your social life without feeling like you have to book it home into bed.

"The big issue is how you’re functioning during the day, so that can be applied to whether you’re sleep deprived or getting too much sleep," he says. "If you’re functioning well and accomplishing your tasks, I’m not really going to dive into your evaluation, whether it’s sleep deprivation or getting too much sleep. If you’re not functioning, that’s something to evaluate."

But if you're getting nine or ten hours of sleep and still having a hard time getting through the day, Dr. Dasgupta says that could be a sign of an underlying sleep disorder that needs to be evaluated by keeping a sleep diary, answering a questionnaire, or other tools like the Epworth Sleepiness Scale (which measures people’s daytime sleepiness).

So if you're feeling sluggish throughout your day and feel like continuous oversleeping (or even under-sleeping) is the problem, you might want to check in with a doctor. But other than that, if you're functioning fine in your day-to-day (okay, maybe with a little help from your morning coffee), getting a few extra hours once and again probably isn't the worst problem to have.