EVEN THOUGH YOU know you need seven to nine hours of sleep a night, you probably don’t always get that much. And you’re not alone—many adults aren’t sleeping enough.
Men are especially lacking sleep. Nearly 40 percent regularly don’t get at least seven hours a night, according to the Centers for Disease Control and Prevention.
While the recommendation to get seven-to-nine hours of sleep isn’t a “hard-and-fast rule,” it’s generally recognized as the ideal amount to achieve a healthy lifestyle and stay alert during the day, explains Anita Naik, D.O., a pulmonologist and sleep medicine physician at MedStar Health in Baltimore, Maryland.
“We do know that less than six hours of sleep chronically and more than nine hours of sleep in adults can actually be detrimental to your health,” she says.
For most people, less than six hours can cumulatively lead to insufficient sleep and what experts call “sleep debt.” That’s where, with each day of insufficient sleep, you can get further behind on your health needs, says Peter Polos, M.D., a pulmonologist and sleep medicine physician at Hackensack Meridian Health in Edison, New Jersey.
Sleep enables your body to rest and recover, and several bodily organs and functions, including your brain, immunity, and metabolism, need it to thrive, Dr. Polos says. “Our mind and body need enough time to rest and recover—which includes consolidation, restoration, and clean-up from the day.”
But it is sometimes tempting to stay up too late and tell yourself that six hours is enough sleep. Here’s the truth about how it can affect your health.
Does everyone need the same amount of sleep?
People are different, and the right amount of sleep definitely is individualized, but it still averages to about seven hours, Dr. Naik says.
“The right amount of sleep means it’s the amount of sleep that’s right for you that allows you to be alert and highly functional during the day without being sleepy during the day,” she says.
Our culture does often value less sleep and more productivity, but it’s generally not healthy, Dr. Naik emphasizes.
There are some people who do well on just six hours a night, however, Dr. Polos says. “Most people who need seven to eight hours [may find those needs] can change over the course of life.”
How do you know if you’re getting enough sleep?
The amount of sleep you get is crucial to feeling rested. But the amount of time you actually spend asleep and how often you wake up during the night also contributes to overall rest.
If you’re getting enough good quality sleep, you’ll wake up feeling refreshed, Dr. Naik says. You feel alert and active. You also don’t need a nap or to keep pouring yourself more cups of coffee.
One way to know if you’re getting enough is to measure how sleepy you are during the day. A famous way to do it is via the Epworth Sleepiness Scale. The CDC offers an interactive tool on its website.
The tool asks you questions like how likely you are to nod off if you’re sitting and reading or as a passenger in a car for an hour or more. A score of 10 or higher indicates that you aren’t getting enough sleep.
What happens if you only sleep six hours a night?
You probably won’t start nodding off at your desk on six hours of sleep–in fact, you might think you’re coping just fine with less shut-eye.
However, you’re probably going to feel more irritable and possibly anxious or depressed if you keep up the habit, according to the National Sleep Foundation.
Your attention span may shorten, and you might find your judgment and reaction skills worsen. That leaves you in danger of not doing well at your job or putting yourself at risk for a car accident, Dr. Naik says. You might also start increasing your dependence on stimulants, like caffeine, to get through the day.
If your sleep dips below six hours a night, your health can suffer, too.
A 2023 study published in The Lancet found that if you sleep that little, plus exercise at a high level, you may have faster cognitive decline than those who sleep the same low amount but don’t work out often. This means your dementia risk can be higher. Keep in mind that while physical activity is great, sleep is the key to restoring and rejuvenating your body so it will perform at its peak for you.
A consistent lack of sleep can affect your testosterone levels, as your body replenishes testosterone during the night. It can also lead to high blood pressure and an increased risk for cardiovascular disease, Dr. Naik says.
Over time, not sleeping enough may lower your metabolism, increase your risk for obesity, and impair your immune system, according to the National Heart, Lung, and Blood Institute.
How can you create and maintain good sleep habits?
If you consistently get six hours of sleep a night, it shouldn’t be that hard to prioritize shut-eye and get that up to seven. (Get the steps to make it happen with our 30-Day Sleep Better Challenge).
Here are some tips:
- Stick to a schedule where you go to sleep and wake up at roughly the same times every day
- Skip naps
- Avoid watching TV or scrolling through your phone right before bedtime
- Don’t eat or drink close to bedtime, especially alcohol and caffeine
- Sleep in a cool, dark room
- Work out at least two hours before you plan to go to sleep, if you prefer to exercise at night
Another important thing to avoid is all-nighters. It may be tempting to stay at the office and power through a project while the rest of the world slumbers, but it will cost you in the long run. If you miss sleep for just one 24-hour period, you can experience many negative side effects, including slurred speech, vision and hearing problems, tremors, and hand-eye coordination problems, according to the Cleveland Clinic.
If you persistently have trouble falling asleep or don’t stay asleep, and you’re not sure why, talk to your primary care physician, Dr. Naik emphasizes. Your doctor may refer you to a sleep specialist.
Doctors will discuss your health and sleep history, including whether you snore or wake up with headaches, and rule out any underlying health conditions that could be impacting your sleep. Dr. Naik says you might be recommended for a sleep study to get more information about your sleep problems and find the best treatment.
