Most adults need at least 7 hours of sleep per night. The American Academy of Sleep Medicine and the Sleep Research Society issued a joint recommendation stating that seven or more hours is necessary to sustain health and safety, and that six or fewer hours is inadequate. Beyond that baseline, the exact number depends on your age, activity level, and individual biology.
Recommended Hours by Age
Sleep needs change dramatically across a lifetime. Newborns need the most, spending 14 to 17 hours asleep per day, while older adults need the least. Here’s what the current guidelines recommend:
- Newborns (0 to 3 months): 14 to 17 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
- Teens (13 to 18 years): 8 to 10 hours
- Adults (18 to 60 years): 7 or more hours
- Older adults (61 to 64 years): 7 to 9 hours
- Seniors (65 and older): 7 to 8 hours
For children, those totals include naps. By school age, most kids consolidate their sleep into a single overnight stretch, though the number of hours they need remains well above the adult minimum.
Why 7 Hours Is the Floor, Not the Target
Seven hours is a minimum, not an ideal. The expert panel that developed the adult recommendation deliberately chose not to set an upper limit, noting that more than nine hours per night may be perfectly appropriate for young adults, people recovering from sleep debt, or those fighting illness. In practical terms, most healthy adults feel best somewhere between 7 and 9 hours.
Your body cycles through distinct sleep stages roughly every 80 to 100 minutes, and you typically complete four to six of these cycles per night. Each cycle includes lighter sleep, deep sleep, and REM sleep (the stage linked to dreaming and memory processing). Cutting your night short doesn’t just reduce total sleep. It disproportionately cuts into the later cycles, which contain longer stretches of REM. That’s why six hours of sleep doesn’t feel like “close enough” to seven. You may be losing a full cycle’s worth of the most restorative stages.
What Happens When You Don’t Get Enough
Sleeping six or fewer hours on a regular basis raises the risk of a long list of chronic conditions, including type 2 diabetes, heart disease, obesity, and depression. These aren’t just statistical associations in extreme cases. The consensus among sleep researchers is that chronically short sleep is a direct threat to cardiometabolic health, sitting alongside diet and exercise as a pillar of disease prevention.
The effects show up in daily life well before any chronic disease develops. Reaction time slows, emotional regulation suffers, and the ability to concentrate drops measurably after even one or two nights of restricted sleep. People who are chronically underslept often don’t realize how impaired they are because they’ve adjusted to feeling that way.
Can Some People Thrive on Less?
You’ve probably heard someone claim they only need five or six hours. A genuine condition called short sleeper syndrome does exist, where certain genetic mutations allow a person to function well on less than six hours without any negative effects. But it’s exceptionally rare. Researchers have identified only about 50 families worldwide carrying the relevant mutations. The vast majority of people who believe they’re fine on minimal sleep are simply accustomed to being sleep-deprived.
There’s no reliable self-test for this. If you need caffeine to get through the afternoon, feel drowsy during passive activities like watching TV, or fall asleep within minutes of lying down, you’re almost certainly not a natural short sleeper.
Is Sleeping Too Much a Problem?
Regularly sleeping more than nine hours and still feeling unrefreshed is worth paying attention to. Long sleep duration is associated with type 2 diabetes, heart disease, obesity, depression, and a higher overall risk of dying from a medical condition. However, the relationship is nuanced. As Johns Hopkins neurologist Charlene Gamaldo has noted, the causation likely runs in the opposite direction: underlying illness leads to more time in bed, rather than extra sleep causing the illness.
If you consistently need more than 8 or 9 hours to feel rested, it could point to poor sleep quality (from conditions like sleep apnea) or an underlying health issue rather than a simple need for more hours. The key distinction is whether long sleep leaves you feeling restored or still exhausted.
Athletes and Active People
If you exercise intensely or train for a sport, the 7-hour minimum still applies, but your real need is probably higher. Both the International Olympic Committee and the NCAA have identified sleep as a major contributor to athletic performance and mental health, emphasizing a minimum of 7 hours for adult athletes. Studies show that athletes sleeping less than 6 hours per night face a significantly higher risk of injury.
Physical recovery happens primarily during deep sleep, when the body releases growth hormone and repairs tissue. More training volume generally means more repair work, which means more sleep. Many elite athletes aim for 9 to 10 hours during heavy training blocks.
How to Tell If You’re Getting Enough
The simplest test is how you feel during the day. Sleep researchers use tools like the Epworth Sleepiness Scale, a quick questionnaire that asks how likely you are to doze off in various situations (reading, watching TV, sitting in traffic). A score of 10 or higher suggests you aren’t getting adequate sleep, either in quantity or quality.
You can also run a simpler experiment on your own. During a stretch when you don’t need an alarm (a vacation works well), go to bed when you’re tired and wake up naturally for several days in a row. After the first couple of days, when you’ve paid off any accumulated sleep debt, the amount you naturally sleep is a reasonable estimate of your personal need. Most people land between 7 and 9 hours, and that number tends to stay fairly stable throughout adulthood.