How much sleep do I need? Recommended hours by age, and how to tell whether you are getting enough

The short answer

If you are an adult under 60, you need seven or more hours of sleep a night, on a regular basis. That is the joint position of the American Academy of Sleep Medicine and the Sleep Research Society, based on a panel review of the evidence linking sleep duration to health. The same panel agreed that six hours or fewer is not enough to support optimal health in adults, and it deliberately set no upper limit.

Seven is a floor, not a target: the panel also agreed that seven to nine hours is appropriate for healthy adults, and many people function best nearer eight. The question that matters is "what does my body need, and am I getting it?"

Recommended sleep by age

Sleep need falls steadily from infancy to adulthood. The child and teenage figures below are the AASM consensus recommendations as reproduced by the NHLBI; the adult figures are those the CDC publishes, from the AASM/SRS statement up to age 60 and the National Sleep Foundation for older adults. All are per 24 hours.

• Infants, 4 to 12 months: 12 to 16 hours, including naps
• Toddlers, 1 to 2 years: 11 to 14 hours, including naps
• Preschoolers, 3 to 5 years: 10 to 13 hours, including naps
• School-age children, 6 to 12 years: 9 to 12 hours
• Teenagers, 13 to 18 years: 8 to 10 hours
• Adults, 18 to 60 years: 7 or more hours
• Adults, 61 to 64 years: 7 to 9 hours
• Adults, 65 and over: 7 to 8 hours

The AASM made no recommendation for babies under four months; the CDC lists 14 to 17 hours for newborns aged 0 to 3 months, a National Sleep Foundation figure. The AASM/SRS statement stops at 60, which is why the older-adult rows come from a different body; the floor of seven hours is the same.

Why the range is a range

Seven to nine is a range because sleep need varies substantially between people: the panel's discussion points to a substantial genetic contribution, shown in twin studies, with psychological, behavioural, social and environmental factors, and undiagnosed sleep disorders, explaining much of the rest.

Sleeping more than nine hours is not automatically a problem either. The panel agreed that longer sleep benefits some people, such as younger adults and those recovering from sleep loss, and it could not reach consensus that long sleep is physiologically harmful. Long sleep is linked with higher mortality, but the panel thought it plausible that illness explains much of that association, and said the link may be driven more by underlying disease than by sleep itself. If you sleep long, ask why rather than forcing yourself to sleep less.

To find your own number, keep the same bedtime and wake time for two weeks, skip the alarm whenever you can, and notice how many hours you settle into once you are no longer paying off a deficit.

Signs you are not getting enough

Insufficient sleep does not always feel like sleepiness. The evidence the AASM/SRS panel reviewed links short sleep with poorer attention, processing speed and working memory, and with higher rates of obesity, diabetes, high blood pressure, heart disease and depression. The signs worth checking in yourself are simpler:

• You need an alarm to wake every single day, and you hit snooze.
• You doze off during quiet activities: reading, watching television, sitting as a passenger.
• You sleep noticeably longer on days off than on work days.
• Your mood, patience and concentration improve markedly after a few good nights.
• You rely on caffeine to get through the afternoon.

The second point is also a safety issue: the panel found crash risk rises in drivers reporting less than six hours, so never drive when you feel sleepy. And if you fall asleep unintentionally in the day, or feel heavily sleepy despite enough hours in bed, talk with your doctor. The CDC advises raising signs of the common sleep disorders it lists, which include sleep apnea and narcolepsy, with your healthcare provider, and unintended daytime sleep is one of the clearest.

The third point matters too: the NHLBI notes that sleeping more on days off may itself be a sign you are not getting enough during the week.

Can you catch up at the weekend?

Partly. Sleep loss accumulates; the NHLBI's example is that losing two hours a night leaves a fourteen-hour debt after a week. A lie-in will reduce sleepiness and you will probably feel better on Sunday, but two things limit how far it goes.

First, the weekend does not undo the metabolic effects. In a short laboratory study in Current Biology, healthy young adults limited to five hours on weeknights were then allowed to sleep as much as they liked at the weekend. They slept only about an hour more in total, and once the short nights resumed they again ate more after dinner, gained weight and showed reduced insulin sensitivity. Free weekend sleep did not prevent the metabolic effects of the short week. It was a small, nine-night study and says nothing about lasting harm, but it does show that the weekend does not wipe the slate clean.

Second, sleeping in shifts your body clock. Circadian timing was delayed after the weekend in the same study, and the NHLBI cautions that extra sleep on days off can upset the sleep-wake rhythm, making Sunday night's bedtime harder and Monday morning worse.

The more reliable fix is an earlier, consistent bedtime across the week, with naps kept short. Our guides to sleep hygiene and building a bedtime routine cover the practical steps.

When unrefreshing sleep needs a doctor

If you regularly sleep more than eight hours and still do not feel well rested, or you have been sleeping enough by the clock but waking tired for more than a few weeks, talk with your doctor; the NHLBI specifically flags the first pattern as a possible sign of a sleep disorder. Loud snoring, gasping, or pauses in breathing point towards obstructive sleep apnea, and the STOP-Bang self-check is a sensible first step. Lying awake for long stretches most nights despite the chance to sleep points towards insomnia, which is treatable.

In summary

Adults need seven or more hours a night; teenagers eight to ten; younger children more again. Find your own number with a consistent schedule rather than an average. Sleeping in at the weekend helps you feel better but, in the lab study that tested it, did not prevent the metabolic effects of the short week. Never drive sleepy, and if you get the hours and still wake tired or doze off in the day, ask your doctor why rather than pushing through.