In short
For most adults, no. Sleep experts recommend seven or more hours a night. In a controlled study, two weeks of six-hour nights impaired attention as much as going without sleep for up to two nights, and people didn’t notice how impaired they were. A small number of people do need less, but it’s rare.
On this page
The short answer
Six hours is not enough for most adults. The American Academy of Sleep Medicine and the Sleep Research Society reviewed the evidence and recommend that adults sleep seven or more hours a night on a regular basis.1 Australia’s Sleep Health Foundation gives a similar range: most adults need between seven and nine hours.8
What six hours a night does
The clearest evidence comes from a sleep laboratory study. Healthy adults were limited to four, six or eight hours in bed every night for two weeks and tested throughout the day.2
- The eight-hour group stayed steady
- The six-hour group got steadily worse at tasks needing attention and memory. By the end of two weeks their performance had dropped as far as that of people kept awake for up to two nights in a row
- They didn’t feel it. Their own ratings of sleepiness levelled off after a few days while their performance kept falling
That last finding explains why so many people believe they do fine on six hours. You stop noticing.
Sleep still not right?
Talk it through with an Australian doctor online. No referral needed.
Long-term health
A meta-analysis of studies covering more than 1.3 million people found that short sleepers had a 12 per cent higher risk of dying during the study period than people who slept seven to eight hours. Long sleepers had a higher risk too.3
These are associations, not proof that short sleep causes early death. Illness and stress can shorten sleep as well as the other way round. Still, the pattern fits with what experiments show about short sleep and blood sugar, appetite and blood pressure.
Is 7 hours of sleep enough?
For most adults, yes. Seven hours is the bottom of the recommended range, and plenty of people function well on it.1 Some need eight or nine. The test is how you feel and function, not the number.
Some people really do need less
They exist, and they are rare. Researchers have identified families who naturally sleep around six hours and feel fine, and traced it to an uncommon gene variant.4 If you need an alarm to wake up, rely on caffeine to get going, or sleep much longer on holidays, you are probably not one of them.
Can you catch up at the weekend?
Only partly. In an experiment where people slept five hours on weeknights and as long as they liked at weekends, the weekend sleep-ins did not prevent the changes in blood sugar control and the extra night-time eating that short sleep caused.5 A lie-in helps you feel better. It doesn’t cancel the week.
How to tell if you’re getting enough
- You wake up around the same time without an alarm
- You feel alert through the day without needing caffeine to function
- You don’t doze off watching TV, reading or as a passenger
- Your sleep on holidays is about the same length as at home
How to get more sleep
- Fix your wake time first, then move bedtime earlier in 15-minute steps
- Cut caffeine after lunch. Caffeine taken even six hours before bed can take more than an hour off your sleep6
- Protect the hour before bed. Dim lights, no work, screens away
- Treat it as fixed. People who sleep enough usually plan for it. See sleep hygiene
When sleep is short through no choice of yours
If you give yourself enough time in bed and still sleep six hours or less, the cause may be insomnia, sleep apnoea, pain or stress. Sleep problems are common. In a national survey, more than half of Australian adults reported at least one.7 Poor sleep night after night also affects mood, concentration and safety on the road.9
See a doctor if you are regularly sleepy during the day, have nodded off while driving, or have had trouble sleeping for more than a few weeks.
Next step: talk to a doctor
Answer a few quick questions and you’ll get an email about your eligibility. A consultation doesn’t guarantee any particular treatment.
References
- Watson NF, Badr MS, Belenky G, et al. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015;38(6):843-4.
- Van Dongen HP, Maislin G, Mullington JM, et al. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep. 2003;26(2):117-26.
- Cappuccio FP, D'Elia L, Strazzullo P, et al. Sleep duration and all-cause mortality: a systematic review and meta-analysis of prospective studies. Sleep. 2010;33(5):585-92.
- He Y, Jones CR, Fujiki N, et al. The transcriptional repressor DEC2 regulates sleep length in mammals. Science. 2009;325(5942):866-70.
- Depner CM, Melanson EL, Eckel RH, et al. Ad libitum Weekend Recovery Sleep Fails to Prevent Metabolic Dysregulation during a Repeating Pattern of Insufficient Sleep and Weekend Recovery Sleep. Curr Biol. 2019;29(6):957-967.e4.
- Drake C, Roehrs T, Shambroom J, et al. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med. 2013;9(11):1195-200.
- Appleton SL, Gill TK, Lang CJ, et al. Prevalence and comorbidity of sleep conditions in Australian adults: 2016 Sleep Health Foundation national survey. Sleep Health. 2018;4(1):13-19.
- Sleep Health Foundation. How much sleep do you really need?.
- Better Health Channel (Victorian Government). Sleep deprivation.
This guide is general information, not medical advice. It doesn’t replace a consultation with a doctor who knows your history. In an emergency, call 000.