You know too many nights of too little sleep can seriously impair your physical, mental, and emotional health—cue the I’m-sorry-for-what-I-said-before-I-had-my-coffee memes—but research now shows that getting too much shuteye may be just as bad.
A 2015 review of studies found that people who sleep fewer than seven hours a night or more than eight have a significantly increased risk of developing type-2 diabetes. Short and long sleepers also tend to gain more weight than moderate sleepers, according to another study. And then there are the brain effects of prolonged sleep—things like memory impairment in older adults and an increased risk of developing dementia.
“There are several theories regarding increased sleep and its association with obesity and diabetes,” says family medicine doctor, Natasha Bhuyan, MD from Phoenix, AZ. “One theory is that people with sleep apnea have an increased need to sleep longer, and they are also at risk for obesity and diabetes. Another theory is that the long sleep itself is just a symptom of underlying issues, like depression. Certainly, it doesn’t seem that longer sleep duration is the cause of these health hazards; rather, there is some association that needs to be studied further.”
It’s crazy to think you should put a cap on something that’s so good for you, but that’s exactly what some experts recommend. Unfortunately, figuring out whether you’re getting too much sleep—and what to do about it—isn’t cut and dry. Below, advice from leading health experts you won’t want to sleep on.
Are You Getting Too Much Sleep?
As you might expect, sleep patterns (like so many other aspects of health from nutrition to exercise) vary from person to person. And while agencies like the Centers for Disease Control and Prevention (CDC) often cite seven to nine hours a night as the recommended sleep duration for adults, many experts argue that the definitions of “too much” and “too little” sleep are murky.
“The number often floated around is eight hours because it’s the average, but that’s not a set number for everyone,” says Fitbit sleep advisor Allison Siebern, PhD, consulting assistant professor at The Stanford Center for Sleep Sciences and Medicine and director of Sleep Health Integrative Program at the Veterans Affairs Medical Center in Fayetteville, NC. “There’s no definition of too much.”
“The number of hours of sleep you need per night mostly depends on your age and your own body,” says Bhuyan. The younger a person is, the more sleep they require—that’s because sleep directly impacts mental and physical development. Counting naps and nighttime snoozing, newborns typically need to sleep between 14 to 17 hours a day, toddlers need about 11 to 14 hours, preschoolers require 10-13 hours, school age children need 9 to 11 hours, and teenagers require between 8 and 10.
To figure out if you’re getting too much sleep, first you have to know how much you’re currently getting. When worn to bed, all wrist-based Fitbit devices can automatically detect any sleep session at least one hour in duration.
To see your sleep stats, including hours slept, just tap the sleep tile on your Fitbit app dashboard. If you’re using an iOS or Android smartphone, you can then tap the expander icon at the top right of the graph to see average time asleep across various time periods (time asleep is calculated by subtracting your time awake or restless from the overall tracked time. For example, if you slept 8 hours, but woke up twice for 15 minutes each, the time asleep will show 7.5 hours).
There are a few different ways this info may be helpful. “If someone is making changes or making correlations with health factors, looking week by week can be beneficial,” says Siebern. “If someone is noting a change in their sleep (i.e. needing more over time), looking at longer trends can be helpful.”
Once you know what your average time asleep is, start paying attention to how you feel each day. By connecting how much you’ve slept with how you feel, you can start to figure out whether the amount of sleep you’re getting each night is actually the right amount for you.
“If you consistently sleep nine hours and you wake up feeling sluggish and you’re not able to complete both mental and physical tasks without issues throughout the day, then nine hours of sleep might be too much for you,” says Bhuyan. “You could also have an underlying medical condition that needs to be explored, so it’s worth seeing your primary care provider.”
Why Your Body May Be Craving More Sleep
If you know you feel great with seven hours of sleep a night but notice your daily tally is starting to creep upwards, you’d be smart to investigate.
“It’s hard for the body to surpass a sleep hour unless there’s a reason,” says Siebern. “Let’s say someone who is hardwired as a seven-hour sleeper tries to sleep eight to nine hours—they’ll lie in bed and it will not be a nice experience.”
There are a few possible causes, including a busy lifestyle. “Adults may become a little restricted with sleep during the work week due to life responsibilities,” says Siebern. “And on the weekends they may tend to sleep longer than what’s average to make up some of the sleep debt.”
Unfortunately, you can’t really make up for lost sleep by sleeping in one day. If you think you’re in sleep debt, here’s how to balance your bedtime budget. If you do that and still feel overly sleepy, consider whether medicine might be a factor. According to research, one common reason people oversleep is prescription sleep medication which a CDC study says about 4% of U.S. adults aged 20 and over reported taking in the past 30 days. One study found that people using insomnia medication regularly experienced residual effects like drowsiness and impaired memory that interfered with work, home life, and social relationships.
The effects can also be much more serious. “Emerging research shows that sleeping pills are dangerous and linked to increased mortality,” says Bhuyan. “So if you suffer from insomnia, you’re better off finding natural ways to fall asleep (and sleeping a shorter amount) than taking a prescription sleeping medication.”
If sleep medication isn’t the issue, talk to your doctor about the potential of an underlying health condition or whether a prescription medicine you’re currently taking for that condition may be contributing to your fatigue. Many medical conditions are known to cause sleep changes, including:
- Depression and anxiety
- Sleep apnea
- Gastrointestinal disorders, and more
“People with depression often have a hard time waking up in the morning,” says Bhuyan. “People with sleep apnea will wake up [feeling] unrefreshed, snore at night, or sometimes, have episodes where their sleep partner thinks they stopped breathing at night. These conditions can be subtle, so it’s important to see a primary care provider so they can pick up on any small clues.”
If you’re concerned about your sleep stats or the quality of your rest, make an appointment with your doctor to investigate the issue. “It’s important to see your primary care provider for a general health exam so you can discuss your sleeping habits,” says Bhuyan.
And if your doctor rules out any potential medical condition affecting your sleep, then it’s time to do a serious self-assessment on your nightly patterns so you can start to make improvements. Fitbit sleep tools, like bedtime reminders and silent alarms, can help you establish and maintain a consistent sleep schedule.
This information is for educational purposes only and is not intended as a substitute for medical diagnosis or treatment. You should not use this information to diagnose or treat a health problem or condition. Always check with your doctor before changing your diet, altering your sleep habits, taking supplements, or starting a new fitness routine.