How Much Sleep Do You Need? Sleep Duration FAQ

Adults should sleep 7 or more hours a night on a regular basis. Two groups agree on this: the American Academy of Sleep Medicine (AASM) and the Sleep Research Society (SRS). The National Heart, Lung, and Blood Institute (NHLBI) puts it as 7 to 9 hours for adults. Children and teens need more, as the age table further down shows.

The 7-hour line comes from the research behind the AASM and SRS consensus. Regularly sleeping less than 7 hours is linked with several problems in that statement:

• Long-term health: weight gain, obesity, diabetes, high blood pressure, heart disease, stroke, depression and earlier death.
• Day-to-day effects: weaker immune function, more pain, worse performance, more errors and a greater risk of accidents.

These are associations from studies, so short sleep isn't proven to cause each one. Still, the pattern was strong enough for the experts to set 7 hours as the floor.

Yes, hours are only one part. The AASM and SRS name four more needs. Healthy sleep also takes good quality, sensible timing, a regular schedule and no untreated sleep disorder. Seven restless, broken hours won't feel like seven solid ones. If you sleep long enough but still wake tired, mention it to a clinician.

For most adults, no. Six hours falls below the 7-hour minimum that the AASM and SRS recommend. Regular short sleep is linked with weight gain, high blood pressure and depression. It's also tied to more errors and accidents. One short night now and then is common. A steady pattern of 6-hour nights is the thing to fix.

For most adults, yes. Seven hours meets the minimum in the AASM and SRS consensus. The NHLBI recommends 7 to 9 hours, so some people feel better with a little more. If you get 7 hours and wake up rested, you're likely in a good range.

Yes. Eight hours sits comfortably inside the 7 to 9 hour range the NHLBI recommends for adults. It also gives you a buffer for nights when you take longer to fall asleep. Teens are different: they need 8 to 10 hours, so 8 is their minimum.

Only partly. Plenty of people try to catch up on weekends. The National Institute of Neurological Disorders and Stroke (NINDS) addresses this. Depending on how short they've been, extra weekend sleep may not replace what they missed. A regular schedule with enough sleep each night works better. You can total your shortfall with the Sleep Debt Calculator.

The NHLBI says teens aged 13 to 18 need 8 to 10 hours a day. That's more than adults need. NINDS adds that school-age children and teens need about 9.5 hours a night on average. Early school start times can make this hard, so a steady bedtime helps.

Yes, for young children. The NHLBI's recommended hours include naps, and sleep experts consider naps appropriate for children under age 7. A 3-year-old needs 10 to 13 hours. A long nap plus a full night can cover that.

No. NINDS says most adults need 7 to 9 hours a night, even older people. What changes is how easy it is to get. Older adults often have more trouble sleeping. They're also more likely to take medicines that disrupt sleep. The type of sleep also shifts with age, which we explain in the sleep stages FAQ.

Not necessarily. The AASM and SRS say over 9 hours may suit some people. That includes young adults, people catching up on lost sleep and people who are ill. For everyone else, it's uncertain whether regularly sleeping over 9 hours carries a health risk. If you need much more sleep than usual, it's worth asking a clinician why.

The clearest sign is a pattern of fewer than 7 hours on most nights. Track a normal week before you judge. Here's a simple way to check:

1. Log a week. Write down roughly when you fell asleep and woke up each day.
2. Find your average. Add the hours and divide by seven.
3. Compare with the guideline. Under 7 hours on average means you're short.

The Sleep Debt Calculator does the maths for you and charts each night.

Talk to a doctor if you think you're sleeping too much or too little. Both the AASM and the NHLBI give that advice. Raise it sooner if you snore loudly or wake up gasping. The same goes for heavy daytime sleepiness despite enough time in bed. Those can point to a sleep disorder that treatment can help.