Sleeping a Lot—And What It Could Mean

Sleeping a lot isn't necessarily a bad thing. Sleep is important. Not getting enough sleep puts you at risk for health problems, from heart disease to obesity to diabetes. However, sleeping a lot all of a sudden when you didn't before might be a reason to look closely at what is going on with your health.

Experts recommend that adults get seven to nine hours of sleep each night. About one-third of adults (32.8%) get fewer than seven hours of sleep a night. However, it's possible to fall on the opposite side of the recommended adult sleep duration and sleep too much, also known as oversleeping.

Here's what you should know about sleeping too much and how it can affect your health.

What Does Oversleeping Mean?

Medically speaking, oversleeping is sleeping for more than nine hours within a 24-hour timespan. Other than long sleep duration, oversleeping is usually characterized by the need to nap throughout the day, feeling extremely sleepy during the day, and headaches.

In some cases, oversleeping can initially be a result of sleep deficits. "In modern lifestyles, people tend to restrict sleep because of working hours intentionally, caring duties for family members, hobbies, and other activities," Chun Shing Kwok, MBBS, clinical lecturer in cardiology and specialist registrar in cardiology at Keele University and Royal Stoke University Hospital in the UK, told Health.

As a result, you may sleep too much within one or more 24-hour periods to make up for any of the sleep you lost because of a hectic day, week, or month.

However, oversleeping can set the stage for many health problems—including a higher risk of death from any cause. "Our evidence suggests that sleeping more than recommended may be more harmful than sleeping less," Kwok explained, referencing an August 2018 Journal of the American Heart Association for which he was a lead author.

Health Conditions Associated With Oversleeping

In the August 2018 Journal of the American Heart Association meta-analysis, the risk increased with each extra hour of sleep. Sleeping nine hours was associated with a 14% increased risk of dying, 10 hours with a 30% higher risk, and 11 hours with a 47% higher risk. The risk of dying from heart disease and stroke also increased with longer sleep times.

The risk of diabetes increases if you get less than seven or more than eight hours of sleep a night. Furthermore, C-reactive protein (CRP), an indication of inflammation in the body, was higher in individuals who slept less than six hours or more than seven hours—and high levels of CRP are related to increased heart attack risk.

However, none of these studies prove that sleeping longer causes health problems or death. "We only demonstrate associations," Kwok said.

Other Concerns With Oversleeping

Oversleeping is not just a risk factor for health conditions, though. "Sleeping [for a] longer duration may be an indicator for underlying ill-health, like a pre-existing condition that is not detected like heart failure, anemia, hypothyroidism, or obstructive sleep apnea," Kwok said.

In other words, while sleep deprivation may lead to health problems, too much sleep is more likely to indicate something is already wrong.

"The association does not mean causality," added Robert W. Greene, MD, a professor in the departments of psychiatry and neuroscience at the University of Texas Southwestern Medical Center in Dallas. "The fact that you're sleeping too much is probably not causing any problems per se but could indicate that something else bad is going on."

What To Keep in Mind About Sleeping Too Much

Remember that individual sleep needs vary; you might get more than nine hours and be fine. For example, if you're used to sleeping 10 hours and have been sleeping that long each night for years, it's probably not a cause for concern.

And don't stress about one lazy Sunday morning.

"Look for relatively acute changes," Dr. Greene said. "If you used to be a seven-hour sleeper, then all of a sudden you're sleeping a lot more, that might be telling."

A sleep diary, like one from the National Heart, Lung, and Blood Institute (NHLBI), can help log how long you sleep and how you feel after waking up, as well as any factors that may be impacting your sleep, like medications or food. You could also use a fitness tracker with sleep-tracking capabilities to monitor aspects of sleep like deep sleep or rapid eye movement (REM) sleep.

"Clinicians and patients should consider paying attention to how much they sleep as a symptom of ill health," Kwok added. "Doctors should consider screening for sleep-related problems in consultations…as there are clear illnesses associated with tiredness that may result in increased sleep duration."

If you think oversleeping could be a clue that something else is wrong with your health, you can head to a healthcare provider. Figuring it out and treating it could help you start logging a healthier amount of shut-eye.

A Quick Review

In medical terms, oversleeping means sleeping more than nine hours in 24 hours. It's associated with a higher risk of several conditions, including heart disease, stroke, and heart failure.

That doesn't mean it causes those conditions. Instead, oversleeping may be a symptom of other underlying conditions. If you find yourself sleeping too much too often, especially compared to how you usually sleep, check with a healthcare provider to rule out other medical conditions.