Neural Science

Is 6 hours of sleep at night enough?

If you feel like you could use more sleep, you probably aren’t alone. Sleep is essential for optimal health, but getting enough of it every night is easier said than done. So, is six hours of sleep enough?

Many people sleep less than the recommended amount, which is at least seven hours for adults, according to the American Academy of Sleep Medicine. It’s normal to have a bad night once in a while, but what if you’re consistently hitting right below the target?

If you sleep an average of six hours a night, only one hour less than recommended amount adults, you may be curious if it really makes a difference. So, what are the health effects of routinely sleeping six hours a night?

Is 6 hours of sleep enough?

Generally speaking, six hours is not enough sleep for the average person.

The amount of sleep adults need is shaped like a bell curve, and the vast majority of the population falls in the middle between seven and nine hours, Dr. Bhanu Kolla, a sleep physician and psychiatrist at the Mayo Clinic, tells In other words, if people could sleep for as long as their body wants, with no disruptions or alarms, most adults will naturally sleep for that range, Kolla adds.

RELATED: Is 5 hours of sleep enough?

On the sleep needs bell curve, there are people who fall below the average, above it and total outliers.

Some adults need around 10 hours of sleep every night in order to feel rested, and that’s healthy, says Kolla. “The AASM doesn’t have an upper limit in terms for adults in terms of how much sleep you need,” Kolla adds.

Certain individuals require less sleep than the recommended duration, so six hours is enough, the experts note. “If it’s happening naturally, so they’re going to bed when they’re drowsy waking up on their own without an alarm, and they’re consistently getting six hours and functioning very well, it probably is what their body needs,” says Kolla. But this isn’t that common, he adds.

On the extreme end, there are people who can function normally with as little as four hours of sleep. Called “short-sleepers,” these people can naturally sleep less than six hours a night without feeling tired or suffering adverse effects, Kolla adds.

Natural short-sleepers are very rare, Dr. Andrew Varga, a neuroscientist and physician at the Mount Sinai Integrative Sleep Center, tells “These are people who have a family gene mutation. … We’re talking very tiny numbers of people,” says Varga.

“On the flip side, there are lots of people who do sleep less than six hours every night,” says Varga.

Why don’t people get enough sleep?

One-third of adults in the United States report that they usually get less than the recommended amount of sleep, according to the U.S. Centers for Disease Control.

Most people do not get enough sleep because of obligations like work or school, lifestyle choices, poor sleep hygiene, or sleeping disorders, Shelby Harris, PsyD, a clinical psychologist specializing in behavioral sleep medicine and director of sleep health at  Sleepopolis, tells

Examples include excessive substance use (like alcohol) especially if it’s close to bedtime, not exercising enough, too much screen time close to bedtime, consuming too much caffeine and excess napping.

Health conditions can also lead to not getting enough quality sleep, such sleep apnea, which interrupts breathing during the night, and sleep disorders like insomnia, Kolla notes.

Health impact of only getting 6 hours of sleep

Sleeping less than seven hours every night without catching up can lead to chronic sleep deprivation, which increases the risk of a number of health issues, the experts note. Even one night without enough rest can impact the body the following day.

Cognitive impairment and drowsiness

Depending on your baseline level of sleep, six hours may leave you feeling drowsy, fatigued, irritable, or give you the urge to nap throughout the day, says Kolla.

“I think if you were to actually put (people who sleep six hours a night) to the test and look at how they’re functioning during the day cognitively, you would definitely find deficits,” says Varga. These include slower reaction time, poorer working and retrospective memory, difficulty paying attention, and more.

Hurting internal organ function

The link between sleep duration and adverse health outcomes has been well-studied, the experts note. Habitual sleep deprivation can affect every organ of the body, says Varga. It’s linked to an elevated risk of heart attack, stroke, hypertension, heart disease, diabetes, kidney disease and metabolic syndrome, the experts note.

“There seems to be an increased risk (of mortality) and as you go below seven, and the further down that path you go, the higher the risk,” says Kolla.

Mental health problems

Research has shown that sleeping too little is also associated with an increased risk of developing depression, anxiety, bipolar disorder, and Alzheimer’s, Kolla adds.

What’s the recommended amount of sleep?

The amount of sleep you need changes as you age, and individual sleep needs will vary based on a person’s lifestyle, health and environmental factors.

Here are the recommended hours of sleep for each age group, according to the AASM:

  • Infants (4–12 months): 12–16 hours, including naps
  • Toddler (1–2 years): 11–14 hours, including naps
  • Preschool-age children (3–5 years): 10–13 hours, including naps
  • School-age children (6–12 years): 9–12 hours
  • Teenagers (13–18 years): 8–10 hours
  • Adults (18+ years): 7 or more hours

The basics of sleep quality

Sleep quality matters, too. When we sleep, the body will go through through different stages of REM (rapid eye movement) sleep and non-REM sleep, says Varga.

During the recommended seven to nine hours of sleep, we typically go through three to five sleep cycles per night, with the duration of REM sleep getting longer each subsequent time, Varga explains. This is referred to as the body’s “sleep architecture.”

Disrupted or abnormal sleep architecture can worsen the quality of sleep and over time, lead to sleep deprivation, the experts note.

The timing of sleep, when you fall asleep and when you wake up, is also important, says Varga. The 24-hour sleep-wake cycle is regulated by our circadian rhythm, which responds to changes in light, per the National Sleep Foundation.

How to get more sleep

Getting more sleep is not always an easy task, the experts note, but being aware of the potential effects of sleep deprivation is a good first step. It’s important for everyone — adults and children alike — to be prioritizing sleep every night, says Harris.

The experts recommend the following steps to prioritize your sleep:

  • Be consistent: Try to go to bed at the same time and wake up at the same time every day, says Harris.
  • Create a wind-down routine at night to help your body relax.
  • Cut down on screen time at night, and avoid using digital devices 30 minutes to one hour before bedtime, says Varga.
  • Limit caffeine and alcohol intake, says Kolla.
  • Exercise regularly.
  • Avoid napping too close to bedtime.

If you are concerned about your sleep duration or quality, talk to your doctor to rule out any sleep disorders or underlying problems.

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