Most adults need seven to nine hours of sleep a night. That range comes from the National Sleep Foundation and is widely used in clinical practice. Children and teenagers need more, and the amount shifts as the brain and body develop. The table below gives the recommended hours by age group, followed by what the science actually says about why those numbers differ.
How Long Should I Sleep? Recommended Hours By Age
The recommendations below reflect ranges published by the National Sleep Foundation and similar guidance from the American Academy of Sleep Medicine. These are population-level ranges, not personal prescriptions. An individual’s true need can sit anywhere inside the range.
| Age group | Recommended sleep per 24 hours |
|---|---|
| Newborns (0–3 months) | 14–17 hours |
| Infants (4–11 months) | 12–15 hours |
| Toddlers (1–2 years) | 11–14 hours |
| Preschoolers (3–5 years) | 10–13 hours |
| School-age children (6–13 years) | 9–11 hours |
| Teenagers (14–17 years) | 8–10 hours |
| Young adults (18–25 years) | 7–9 hours |
| Adults (26–64 years) | 7–9 hours |
| Older adults (65+) | 7–8 hours |
For infants, these totals include naps. For toddlers and preschoolers, naps make up a large share of the daily total. By school age, most children still benefit from a nap but can often meet their needs with nighttime sleep alone.
One detail worth noting: the older adult range is slightly narrower than the adult range. That does not mean older people need dramatically less sleep. It reflects the way sleep architecture changes with age — lighter sleep, more frequent awakenings, and earlier sleep timing.
Why Do Babies and Children Need So Much More Sleep?
Infancy and childhood are periods of rapid brain development, and sleep is when much of that development happens. During deep sleep, the brain consolidates memories, prunes unused neural connections, and releases growth hormone. The pituitary gland releases most of its growth hormone during slow-wave sleep, which is why sleep and physical growth are tightly linked in early life.
Newborns spend roughly half their sleep time in REM, the stage associated with dreaming and memory processing. By adulthood, REM makes up closer to 20–25% of total sleep. That shift tells you something about how much the young brain depends on sleep for wiring itself.
Sleep also supports immune function and emotional regulation. A sleep-deprived toddler is not just cranky — the brain regions that manage impulse control are less active when sleep is short.
Why Do Teenagers Need 8 to 10 Hours?
Adolescence brings a second wave of brain reorganization, and the sleep need stays high even as social and academic demands increase. Teenagers also experience a well-documented shift in circadian timing. Their bodies naturally want to fall asleep later and wake later — a biological change, not laziness.
This shift, sometimes called sleep phase delay, collides with early school start times. The result is that many teenagers run a chronic sleep debt. Research has consistently linked short sleep in teens to poorer academic performance, higher rates of mood problems, and increased risk-taking behavior. The direction of cause and effect is not always clear, but the association is strong and consistent.
The American Academy of Pediatrics has recommended that middle and high schools start no earlier than 8:30 a.m. to better match adolescent sleep biology. Some districts have made this change, though adoption is far from universal.
What Changes About Sleep After 65?
Older adults still need about seven to eight hours, but the quality of that sleep often changes. Slow-wave sleep — the deepest stage — declines with age. People wake more often during the night and spend more time in lighter sleep stages.
Circadian rhythms also shift earlier. Many older adults feel sleepy in the early evening and wake before dawn. This is a normal part of aging, not necessarily a disorder.
It is worth separating normal age-related change from a sleep problem. Frequent waking that leaves you exhausted during the day is not just “getting older.” It can point to sleep apnea, restless legs syndrome, pain, depression, or medication side effects. These are treatable, and none of them should be dismissed as an unavoidable part of aging.
Some research suggests that poor sleep in older adults is associated with cognitive decline, though whether sleep disruption is a cause, a consequence, or both remains an open question. The evidence does not yet allow a firm conclusion.
Can You Sleep Too Much?
Yes, in a sense — but the picture is more complicated than it sounds. Consistently sleeping well beyond the recommended range has been associated with health risks in observational studies, including cardiovascular disease and higher mortality. However, these studies cannot prove that long sleep causes harm.
In many cases, long sleep is a marker rather than a cause. People who sleep 10 or more hours a night may be doing so because of underlying illness, depression, chronic pain, or poor sleep quality that forces extended time in bed to get enough rest. When researchers account for these factors, the association between long sleep and poor health weakens.
There is also a difference between time in bed and actual sleep. Lying in bed for nine hours while waking repeatedly is not the same as sleeping nine hours straight.
The practical takeaway: if you regularly need far more sleep than the recommended range and still feel tired, that is worth discussing with a clinician. It is not a sign of laziness, and it is not something to self-treat with caffeine or stimulants.
How Do You Know If You’re Getting Enough Sleep?
The best indicator is how you feel and function during the day. If you can stay awake through the afternoon without caffeine, wake up feeling reasonably rested, and maintain steady attention and mood, you are probably meeting your need.
Signs that you may not be getting enough include:
- Needing an alarm to wake up most days and still feeling groggy
- Falling asleep within five minutes of lying down during the day
- Struggling to concentrate or feeling irritable in the afternoon
- Relying on caffeine to get through the day
- Sleeping much longer on weekends than on weekdays
That last point is a useful signal. A large gap between weekday and weekend sleep often means you are carrying a sleep debt during the week.
These are general indicators, not diagnostic criteria. If you suspect a sleep disorder, a clinician can assess you properly. Sleep apnea, for example, cannot be identified from how tired you feel alone — it requires a sleep study or a home screening test.
Does Sleep Quality Matter as Much as Quantity?
Yes. Seven hours of fragmented sleep is not equivalent to seven hours of continuous sleep. Sleep is not a single state — it cycles through light sleep, deep sleep, and REM roughly every 90 minutes. Each stage serves different functions, and waking repeatedly disrupts the cycle.
Alcohol is a common example. It may help you fall asleep faster, but it fragments sleep in the second half of the night and suppresses REM. The total hours may look fine on paper while the actual restorative value is lower.
Sleep environment matters too. A cool, dark, quiet room supports the body’s natural temperature drop and melatonin release that help initiate sleep. None of this is complicated, but it is easy to overlook when the focus is only on clocking enough hours.
Frequently Asked Questions
How many hours of sleep does a 40-year-old need?
Adults aged 26 to 64 are generally recommended to get seven to nine hours of sleep per night. Individual needs vary within that range.
Is 6 hours of sleep enough for adults?
For most adults, six hours falls below the recommended range of seven to nine hours. Some people genuinely function well on less, but this is uncommon, and most people who believe they need less sleep are still accumulating a deficit.
Do older adults need less sleep than younger adults?
Older adults are generally recommended seven to eight hours, slightly less than the seven to nine range for younger adults. The change is modest and reflects shifts in sleep architecture rather than a sharply reduced need.
What is the best sleep schedule for a teenager?
Teenagers need eight to ten hours per night, and their biology favors a later bedtime and later wake time. A schedule that allows for that window consistently, including weekends, supports both mood and academic performance.
