Teen Sleep: Why Teenagers Stay Up Late and How Much Sleep They Need

Many parents watch a child who once fell asleep at 8pm turn into a teenager who is wide awake at 11pm and impossible to wake at 7am. It is easy to blame phones or attitude, but a real biological change is part of the story. Understanding it helps families focus on the changes that actually work.

How much sleep do teenagers need?

The American Academy of Sleep Medicine (AASM), endorsed by the American Academy of Pediatrics, recommends 8 to 10 hours of sleep per 24 hours for teenagers aged 13 to 18. Surveys by the CDC have found that most US high school students get less than 8 hours on school nights.

The teenage body clock shift

During puberty, the timing of the body clock (circadian rhythm) moves later. The evening release of melatonin, the hormone that signals sleepiness, happens later than it did in childhood. Research led by sleep scientist Mary Carskadon showed that this delay is a normal developmental change, not just a habit. In practice, many teens genuinely do not feel sleepy until 10:30 or 11pm.

The problem is that school still starts early. A teen who cannot fall asleep before 11pm and has to wake at 6:15am gets barely 7 hours, night after night.

Why school start times matter

In 2014 the American Academy of Pediatrics recommended that middle and high schools start no earlier than 8:30am, citing the health and academic effects of chronic sleep loss in adolescents. California passed a law in 2019 requiring most high schools to start no earlier than 8:30am. Studies of schools that moved to later start times have generally found that students sleep longer.

What chronic sleep loss does to teens

• Difficulty concentrating, remembering and learning.
• Irritability, low mood and greater emotional reactivity.
• Higher risk of drowsy driving for teens who drive.
• Poorer sports performance and slower reaction times.

What parents can realistically change

1. Phones out of the bedroom at night. Late-night messaging and scrolling push sleep even later. Charging devices in a shared space is the single most effective rule for many families.
2. Morning light. Bright light soon after waking helps pull the body clock earlier. Opening curtains or eating breakfast near a window helps.
3. Dim evenings. Lower lights and fewer screens in the last hour before bed.
4. Limit weekend catch-up. Sleeping in until noon on weekends shifts the clock even later and makes Monday harder. Sleep experts often suggest keeping weekend wake times within about two hours of school days.
5. Watch caffeine. Energy drinks, coffee and some sodas in the afternoon can delay sleep.
6. Protect the schedule, not just the bedtime. Heavy homework loads, late practices and part-time jobs can leave no room for sleep. Sometimes something has to give.

When to talk to a doctor

If your teen regularly cannot fall asleep until very late even with good habits, snores loudly, falls asleep during the day, or seems persistently low or anxious, talk to their doctor. Some teens have a more extreme body clock delay (delayed sleep-wake phase disorder) or other sleep problems that benefit from professional help.

Common questions

Is it normal for my teenager to sleep until noon on weekends?

It is common, and usually a sign of sleep debt from the school week. Keeping weekend wake times within about two hours of school days helps prevent the body clock from drifting even later.

Should teens nap after school?

A short nap of 20 to 30 minutes in the early afternoon can help some teens. Long or late naps can make it harder to fall asleep at night.