Most adults need at least 7 hours of sleep per night. The CDC recommends 7 or more hours for anyone between 18 and 60, with a slightly narrower window of 7 to 9 hours for those 61 to 64, and 7 to 8 hours for adults 65 and older. But the right amount for you depends on your age, your body, and how you actually feel during the day.
Recommended Sleep by Age
Sleep needs change dramatically across a lifetime. Newborns (0 to 3 months) need 14 to 17 hours a day. Infants 4 to 12 months old need 12 to 16 hours including naps, and toddlers (1 to 2 years) need 11 to 14. Preschoolers require 10 to 13 hours, and school-age kids (6 to 12) need 9 to 12.
Teenagers need 8 to 10 hours, which is more than most of them get once school schedules, homework, and screens enter the picture. By adulthood, the baseline settles at 7 hours as a minimum. That number holds remarkably steady from age 18 all the way through your 60s, though older adults tend to have a tighter ceiling. Past 65, regularly sleeping more than 8 hours may not offer additional benefit and could signal an underlying health issue worth investigating.
Why 7 Hours Is the Floor, Not the Target
Seven hours is the minimum threshold for most adults, not the sweet spot. Many people function best at 7.5 to 8.5 hours. The way to find your number is straightforward: if you need an alarm clock to wake up, feel drowsy in the afternoon, or fall asleep within minutes of lying down, you’re likely not getting enough.
A small number of people genuinely thrive on 6 hours or less. These natural short sleepers carry mutations in specific genes (DEC2 or ADRB1) that allow their brains to accomplish restorative sleep more efficiently. Researchers have identified roughly 50 families with these genetic traits so far. If you feel fully alert and energetic on less than 7 hours without caffeine propping you up, you may be one of them. But most people who believe they’re fine on 5 or 6 hours are simply accustomed to feeling impaired.
What Happens When You Don’t Get Enough
Sleep deprivation affects your brain before you notice it. Being awake for 17 hours straight produces cognitive impairment equivalent to a blood alcohol level of 0.05%. At 24 hours awake, it’s equivalent to 0.10%, which is above the legal driving limit in every U.S. state. Reaction time, decision-making, and emotional regulation all deteriorate well before you feel “really tired.”
The long-term consequences are more serious. Adults who regularly sleep fewer than 5 to 6 hours per night face a 48% higher risk of developing coronary heart disease or dying from it, and a 15% higher risk of stroke. A large national study found that people sleeping 5 hours or less had significantly higher all-cause mortality compared to those sleeping 7 to 8 hours.
During pregnancy, sleep becomes even more critical. Women who consistently get fewer than 6 hours over a 24-hour period have higher rates of preeclampsia, gestational diabetes, longer labors, and cesarean delivery.
Oversleeping Carries Risks Too
Regularly sleeping more than 8 hours is also linked to worse health outcomes, though the association is weaker than with short sleep. In the same national mortality study, sleeping more than 8 hours was associated with a 32% higher risk of death from all causes compared to the 7-to-8-hour group. This doesn’t mean long sleep causes harm directly. It often signals other problems like depression, chronic pain, sleep apnea, or other conditions that fragment sleep and make it less restorative, prompting the body to stay in bed longer.
Quality Matters as Much as Quantity
Not all sleep is equal. Your brain cycles through distinct stages each night, and the deep sleep stage is where the most physical restoration happens: tissue repair, immune strengthening, and memory consolidation. Adults should spend roughly 20% of their total sleep time in deep sleep, which works out to about 60 to 100 minutes during an 8-hour night. Deep sleep is concentrated in the first half of the night, which is one reason cutting your sleep short by going to bed late is particularly costly.
Your body’s internal clock plays a major role in sleep quality. As daylight fades, your brain detects the dimming light and releases a small burst of melatonin, which triggers a cascade of neurochemicals that prepare you for sleep over the next few hours. Working with this natural signal, rather than against it, means keeping a consistent bedtime and limiting bright light exposure (especially from screens) in the evening. People who go to sleep and wake at roughly the same time each day tend to fall asleep faster and spend more time in the restorative stages.
Weekend Catch-Up Sleep Doesn’t Work
If you’re sleeping 5 hours on weeknights and planning to make it up on Saturday, the research is not encouraging. A controlled study at the University of Colorado assigned healthy young adults to either consistent sleep restriction (5 hours per night), sleep restriction with weekend recovery, or a full-sleep control group. The weekend recovery group slept in freely on Saturday and Sunday but only managed an extra 1.1 hours per night on average, nowhere near enough to erase 5 nights of lost sleep.
More importantly, the metabolic damage persisted. The weekend recovery group showed a 9% to 27% decrease in insulin sensitivity (how well your body processes blood sugar) when they returned to short sleep the following week. Their circadian rhythms shifted later, they ate more after dinner, and they gained weight. The researchers concluded that weekend recovery sleep is not an effective strategy for preventing the metabolic disruption caused by chronic short sleep. The only real fix is consistent, adequate sleep throughout the week.
How to Tell if You’re Getting Enough
Rather than fixating on a specific number, pay attention to a few practical signals. You’re likely getting enough sleep if you wake up without an alarm feeling reasonably refreshed, stay alert through the afternoon without caffeine, and don’t fall asleep instantly the moment you sit in a dark room. One clinical tool, the Epworth Sleepiness Scale, asks you to rate how likely you are to doze off in eight everyday situations like sitting and reading or watching TV. A score of 10 or higher suggests you need more sleep, better sleep habits, or a medical evaluation for a sleep disorder.
If you’re consistently in bed for 7 to 8 hours but still feel exhausted, the problem may be sleep quality rather than quantity. Snoring with gasping, frequent nighttime awakenings, or waking with headaches can all point to conditions like sleep apnea that prevent your brain from reaching the deeper, restorative stages. In those cases, sleeping longer won’t help until the underlying disruption is addressed.