Getting enough sleep is essential for good health. Even if you aspire to sleep eight hours, sometimes life gets in the way and it ends up being closer to five — but is five hours of sleep enough?
One-third of adults in the United States report that they usually get less than the recommended amount of sleep, seven or more hours, according to the U.S. Centers for Disease Control.
Is it OK to sleep five hours once in a while? What are the health effects? We spoke to a few sleep experts to find out.
Is 5 hours of sleep enough?
No, not for the vast majority of people. “Five hours is just too little sleep, especially if you’re doing it routinely," Shelby Harris, PsyD, clinical psychologist specializing in behavioral sleep medicine and director of sleep health at Sleepopolis, tells TODAY.com.
Generally speaking, the human body knows how long it needs to rest.
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“If you have no external pressures and could go to sleep once you feel drowsy, sleep the amount of time the body needs, then wake up without having to use an alarm, feeling rested. ... That is how much you need,” Dr. Bhanu Kolla, a sleep physician and psychiatrist at the Mayo Clinic, tells TODAY.com.
In this situation, most adults will naturally sleep seven to nine hours, says Kolla, which is why the American Academy of Sleep Medicine recommends at least seven hours a night. Infants and children need much more sleep than adults. Sleep needs can also vary based on a person’s genetics, underlying health, behavior and environment, per the ASSM.
The sleep needs of the adult population are more or less shaped like a bell curve, says Kolla, so most people fall in the middle (seven to nine hours). Some won't feel rested unless they sleep nine or 10 hours, and that's OK, Kolla adds. Other people can function on closer to five, but this amount is not optimal for health, especially if it becomes a habit, according to experts.
There are "natural short-sleepers" who can sleep less than six hours a night and function normally without feeling tired or facing adverse health outcomes, Dr. Andrew Varga, a neuroscientist and physician at the Mount Sinai Integrative Sleep Center, tells TODAY.com. But this is a tiny subset of the population — short-sleepers have a very rare inherited gene mutation, Varga adds.
Many people try to convince themselves they are short-sleepers, says Harris, but sleeping an average of five hours a night is more often due to life circumstances, poor sleep hygiene, environmental factors or sleep disorders.
We all have rough nights sometimes, but it's important to be aware that sleeping too little has short-term and long-term consequences.
Health impact of only sleeping 5 hours a night
After sleeping five hours in one night, most people can catch up with one or two nights of sleeping their usual amount or a few hours extra, says Kolla. A short nap the next day can also help.
People who consistently sleep less than seven hours a night may learn to adapt and not feel as sleepy over time as the body racks up sleep debt, Kolla explains. But getting used to not sleeping enough doesn't stop other harmful health effects from taking place.
For example, when sleeping too little becomes a pattern and you don’t catch up, this can lead to chronic sleep deprivation, which is associated with a host of long-term health effects, the experts note.
Cognitive functioning
In the short term, not sleeping enough can impact cognitive functioning. "Even with one night of very little sleep in comparison to what your baseline might normally be, we see issues with impairment," says Harris.
In addition to feeling sleepy the following day, you may have difficulty concentrating, remembering things, a slower reaction time, and you might be more irritable than usual, the experts note.
Accidents and falls
Losing too much sleep can impair one's functioning similar to a blood alcohol content of .08% (legally drunk), Harris explains. The less sleep, the greater risk of accidents and falls, she adds.
Heart and kidney problems
In the long term, people who habitually sleep less than six hours have a higher incidence of high blood pressure and heart attacks, says Varga, as well as stroke, heart disease, kidney disease and diabetes, the experts note.
Depression and other mental issues
Research has shown that sleep deprivation is associated with an increased risk of psychiatric illnesses, says Kolla, including depression, anxiety, bipolar disorder, as well as neurological diseases like Alzheimer’s.
The National Sleep Foundation's 2023 Sleep in America Poll, which surveys a nationally representative sample of the U.S. population, found that 7 in 10 (65%) adults who are dissatisfied with their sleep experience mild or greater levels of depressive symptoms.
"Over what length of time these health consequences start to kick in, it's hard to tell, but we know the longer you go getting very little sleep, the greater risk," says Kolla.
What's the recommended amount of sleep?
People have different sleep requirements during different stages of life, says Kolla; infants and young children need much more sleep than adults and older adults. How much sleep you need will also vary slightly depending on your health, lifestyle, activity level.
The recommended sleep duration for each age group, according to the American Academy of Sleep Medicine and CDC, is:
- Infants (4–12 months) need 12–16 hours, including naps
- Toddlers (1–2 years) need 11–14 hours, including naps
- Young children (3–5 years) need 10–13 hours, including naps
- School-age children (6–12 years) need 9–12 hours
- Teenagers (13–18 years) need 8–10 hours
- Adults (18+ years) need 7 or more hours
Quality of sleep
Generally, you know you got enough sleep “if you awaken feeling refreshed and you’re able to function throughout your day at a normal level without overwhelming sleep drive or the need to take naps” says Varga.
Sleep quality matters too, the experts note. People should be progressing through the various sleep cycles, including non-REM and REM sleep, for the appropriate amount of time. This is referred to as your "sleep architecture," Varga adds.
A disrupted sleep architecture can impact sleep quality and lead to sleep deprivation. One of the most common disruptions is sleep apnea, which causes breathing abnormalities through the night, says Kolla. Sleep disorders such as insomnia and environmental factors can also disrupt sleep architecture.
“If people are getting a sufficient amount of hours of sleep (but) waking up not feeling rested or still feel sleepy through the day, that may be an indication that the quality is poor,” says Kolla.
It's also important to be as consistent as possible with the amount of time you're sleeping and the timing, the experts note.
How to get more sleep
The first step to getting more sleep is treating sleep like a priority, says Harris. It's easier said than done. Here are some tips to try.
Limit time on devices
Spending time on our devices, scrolling through social media or watching videos often takes priority instead and keeps people awake, Kolla notes.
"Screens emit blue light, which is a wavelength that hits neurons ... involved in regulating sleep and wakefulness," says Varga, adding that this can delay your circadian rhythm so you may feel sleepy or fall asleep later than normal. While this isn't a problem for everyone, says Varga, he does recommend avoiding screens for 30 minutes to an hour before bedtime.
It’s just as important to set limits and impose wind-down routines for children as it is for adults, Harris emphasizes. “I think people need to parent ourselves, essentially,” she adds.
Limit substance use
Substances can also influence sleep, says Kolla, namely caffeine and alcohol. These can delay or disrupt sleep, especially when consumed excessively or too close to bedtime, Kolla adds.
Exercise
Exercising regularly can help promote healthy sleeping habits, the experts note, as well as a balanced, nutritious diet.
If you're concerned about your sleep habits or they are impacting your daily life, talk to your doctor, the experts note. "There's a big difference between having insomnia or sleep apnea versus people who are just not making sleep a priority," says Harris.