Natural short sleepers are people with rare gene variants who feel fully rested on about six hours of sleep or less, and you cannot train yourself to become one. Most people who cut back on sleep do not adapt. Experts recommend adults sleep seven or more hours a night. In one two-week lab study, six hours a night impaired thinking about as much as up to two nights without sleep, and people were largely unaware of it. What you can train is sleep quality: a steady schedule, morning light, and treating problems like sleep apnea or insomnia help you get more from the hours you sleep. To find your real need, try a sleep vacation with no alarm for a week or two. This is educational information, not medical advice.
From the practice
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What are natural short sleepers?
Natural short sleepers are people who sleep about six hours or less for most of their lives and feel rested, alert, and healthy. It is a rare trait, and in some families it is tied to specific gene variants.
The first one was found in 2009. UCSF researchers studying a mother and daughter who had slept little for most of their lives found a mutation in a gene called DEC2, which helps regulate circadian rhythms. Mice engineered with the same mutation slept less too. A later study found the mutation increased orexin, a wake-promoting signal, in the mutant mice. Since then, researchers have found other variants, including one in a gene called ADRB1.
These variants are rare. In the original study, no other carriers turned up in a sample of 250 people. The American Academy of Sleep Medicine (AASM) says only a small percentage of adults are short sleepers who feel alert and refreshed on less than six hours.
Here is how a natural short sleeper tends to differ from someone who is simply running on empty:
More likely a natural short sleeper
- You have slept little for most of your life, not just since a stressful job or a new baby.
- You wake up on your own, alert, without an alarm or heavy caffeine.
- Given free time with no alarm, you still settle into short, steady sleep.
More likely sleep restricted
- You need an alarm and caffeine to get going.
- You sleep much longer on days off or vacations.
- Your focus, mood, or memory slip, even though you say you feel fine.
The researcher who found DEC2, Ying-Hui Fu, has noted that people who say they need only six hours usually lean on stimulants like coffee and alarm clocks. She also cautions that most people who habitually sleep less than eight hours are building up sleep debt, not carrying a gene.
Can you train yourself to need less sleep?
No. You can train yourself to feel less sleepy, but that is not the same as needing less sleep.
In a well-known two-week lab study, healthy adults were limited to 4 or 6 hours of sleep a night. Their attention and thinking got worse every day. Their sleepiness ratings jumped at first, then barely changed, and did not clearly separate the 4-hour and 6-hour groups. The researchers concluded that people were largely unaware of how impaired they had become.
That is why “I’m used to it” is such a trap. Caffeine, deadlines, and a busy day can cover up the gap, but the gap is still there. If you are curious what happens at the extreme end, read what four hours of sleep costs your performance.
Does polyphasic sleep let you get by on less?
No. Polyphasic sleep splits sleep into several short episodes across the day, and its fans claim you can thrive on as little as two hours total. A 2021 National Sleep Foundation panel reviewed 22 relevant papers and found no evidence supporting benefits. It linked these schedules, and the sleep deficiency built into them, with adverse physical health, mental health, and performance outcomes, and it does not recommend them.
Splitting your sleep does not shrink how much you need. It just makes it easier to get too little.
Do you suspect you run on too little sleep but can’t seem to sleep longer, even when you try? If you would like to see how we might be able to help you with this deeper, schedule a free consult here.
What can you train? Getting more from the hours you sleep
You cannot shrink your sleep need, but you can make the sleep you get work harder. These steps are the practical levers:
- Keep a steady wake time, including weekends. A regular schedule helps your body clock settle. See our guide to chronotype and your natural timing.
- Treat what breaks up your sleep. Sleep apnea, pain, restless legs, depression, and an enlarged prostate are among the treatable causes the American College of Physicians (ACP) says to look for in insomnia.
- Keep caffeine to the morning and alcohol earlier or lower. Both can cost you sleep quality even when your hours look fine.
- Consider CBT-I if your sleep is broken. The ACP recommends cognitive behavioral therapy for insomnia first. Evidence summaries report it reduces time awake after falling asleep and improves sleep efficiency. Read about CBT-I and sleep efficiency.
Be honest with yourself about the goal. These steps help you feel better on the sleep you need. They do not turn seven hours of need into five.
How do you find out how much sleep you actually need?
Take a sleep vacation. The AASM-style baseline for adults is seven or more hours, but individual need varies, and a sleep vacation shows yours.
- Pick a stretch of days. Harvard’s sleep medicine program suggests several days, ideally during a vacation. Some guides suggest a week or two.
- Keep a consistent bedtime and skip the alarm. Go to bed when you are tired and wake naturally.
- Track your sleep and how you feel. Note bedtime, wake time, naps, and daytime energy.
- Expect long sleeps first. You may sleep longer early on to pay back sleep debt. Your real need shows up once your sleep settles.
- Plan backward from your wake time. Once you know your number, protect that many hours in bed.
If you cannot take time off, work backward from your wake time to get at least your best estimate of your ideal length. If you settle at six hours or less and feel great, mention it to a clinician. If you need nine or more hours, check in with a clinician too. For reference, the AASM and Sleep Research Society say sleeping more than nine hours may be appropriate for young adults, people recovering from sleep debt, and people with illnesses.
For more on the full question, read how much sleep you really need.
What the Research Shows
Short-sleeper genes are real but rare. In 2009, UCSF researchers reported a DEC2 mutation in a mother and daughter who were natural short sleepers. Mice carrying the mutation slept about 1.2 hours less with one mutant copy and 2.5 hours less with two copies. A later PNAS study found DEC2 normally suppresses orexin and that the human mutation weakens that brake, and it noted a second DEC2 variant in other short sleepers. A 2019 Neuron paper reported a mutation in the ADRB1 gene in another family of short sleepers, and the authors noted it is probably not the only gene involved.
Cutting sleep backfires in ordinary people. A 2003 study in Sleep randomized healthy adults to 4, 6, or 8 hours a night, or no sleep, for 14 days. Chronic 4-hour and 6-hour sleep produced cumulative, dose-dependent drops in cognitive performance. Six hours or less for 14 days produced deficits equal to up to two nights of total sleep deprivation. Subjective sleepiness showed only small further increases after the first days, so participants were largely unaware of their decline.
Seven or more hours is the consensus. A 2015 joint statement from the AASM and Sleep Research Society says adults should sleep seven or more hours a night. It links regularly sleeping less than seven hours to weight gain, diabetes, high blood pressure, heart disease, stroke, depression, and increased risk of death, along with impaired performance and more accidents. The panel did not set an upper limit.
Polyphasic schedules lack support. A 2021 National Sleep Foundation consensus report in Sleep Health screened 40,672 publications and kept 22 relevant papers. It found no evidence of benefits and concluded that schedules that sharply cut total sleep or fragment it are associated with a variety of adverse health and performance outcomes.
This article is for education only and is not medical advice. Talk with a qualified clinician about your own sleep, health conditions, and medications.
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When to Seek Professional Help
- You sleep six hours or less and feel unrefreshed, foggy, or dependent on caffeine to get through the day.
- You cannot sleep enough even when you give yourself time in bed. Chronic insomnia is treatable, and CBT-I is the first-line option.
- You snore loudly, gasp or choke at night, wake with headaches, or stay very sleepy despite enough hours in bed. These can signal sleep apnea.
- You feel drowsy while driving or nearly nod off at the wheel.
- You feel unusually energized with little need for sleep for days at a time, or your mood swings sharply. A reduced need for sleep can be a sign of a mood episode, so talk with a clinician promptly.
If you would like to see how we might be able to help you with this deeper, schedule a free consult here.
Frequently Asked Questions
Can you train your body to need less sleep?
No. Your sleep need is set largely by biology, and cutting back does not shrink it. In a two-week lab study, people limited to four or six hours a night showed steadily worsening attention and thinking, while their own sleepiness ratings barely changed after the first few days. So you may learn to feel less sleepy without becoming less impaired. What you can improve is sleep quality: a steady schedule, morning light, and treating issues like sleep apnea or insomnia.
What is the short sleeper gene?
The short sleeper gene usually means DEC2, the first gene linked to natural short sleep. In 2009, UCSF researchers found a DEC2 mutation in a mother and daughter who slept far less than average yet felt rested. Researchers later found other variants, including one in a gene called ADRB1. These variants are rare. In the first study, no other carriers turned up in a sample of 250 people. Most people who sleep six hours or less do not have one.
Is 6 hours of sleep enough for most adults?
For most adults, no. The American Academy of Sleep Medicine and Sleep Research Society say adults should sleep seven or more hours a night. Regularly sleeping less than seven hours is linked to weight gain, diabetes, high blood pressure, heart disease, stroke, depression, impaired performance, and accidents. A small percentage of adults are natural short sleepers who feel alert after less than six hours, but that is the exception. If you are unsure, try a sleep vacation.
Does polyphasic sleep let you get by on less sleep?
No. A 2021 National Sleep Foundation panel reviewed the evidence and found no support for benefits from polyphasic schedules, which split sleep into several short episodes. The panel linked those schedules and the sleep deficiency they cause with adverse physical health, mental health, and performance outcomes, and it does not recommend them. Splitting your sleep does not reduce how much you need. If you want fewer hours in bed, improving sleep quality is the safer route.
How do I know if I’m a natural short sleeper?
A true natural short sleeper has slept about six hours or less for most of their life, wakes alert, and feels well without heavy caffeine. To test yourself, take a sleep vacation: for a week or two, keep a steady bedtime and skip the alarm. You may sleep longer at first to pay back debt. If you settle into short, steady sleep and function well, mention it to a clinician.
When to Work With a Sleep Consultant
If you feel you need more sleep than your schedule allows, or you sleep poorly even with enough hours in bed, a deeper cause may be involved: your circadian rhythm, nervous system, hormones, gut, or nutrient status. The Sleep Consultant looks for those root causes instead of handing you generic sleep-hygiene tips.
