Teens sleep a lot because their bodies need extra rest for rapid physical, mental, and emotional growth, plus a natural shift in their internal body clock (circadian rhythm) makes them feel sleepy later at night but early school starts prevent them from getting enough sleep, leading to sleep debt. This biological shift, combined with late-night screen time, social demands, homework, and extracurriculars, creates a cycle where teens need more sleep but get less, causing them to sleep in or nap.
In adolescents, the main causes of excessive daytime sleepiness are sleep deprivation, inadequate sleep hygiene, insomnia disorders, circadian rhythm disorders, chronic somatic pathologies, psychiatric disorders, movement disorders related to sleep, respiratory disorders related to sleep, parasomnias, hypersomnia ...
While napping and sleeping late on weekends are common behaviors among teens, sleeping more than ten hours per 24-hour period is not just a “normal” part of adolescence. Oversleeping can be a sign of mental health problems like depression and anxiety, and may even contribute to such issues if not managed.
Around one in four adolescents sleep less than six hours a night, well below the recommended amount of eight to ten hours. Some teenagers, however, may remain tired even when they get sufficient rest. This could have to do with their nutrition, stress, or a health condition, whether sleep-related or otherwise.
Teens need more sleep because they are in a time of very fast physical, intellectual and emotional growth. Although getting enough sleep may not seem that big of a deal, medical research shows that teens who usually get too little sleep are more likely to struggle in school.
There's no single "hardest" age, but many parents and experts point to ages 14-16 as particularly challenging due to intense hormonal shifts, social pressures, identity formation, increased desire for independence, and conflicts with parents as teens push boundaries, with some studies suggesting 14 (especially for girls) and 15 (for boys) are peak difficulty points.
While everyone occasionally sleeps in, chronic oversleeping — needing 10, 11 or more hours regularly — can be linked to underlying health issues. “Conditions like thyroid disorders, anemia or sleep apnea can all lead to excessive fatigue and longer sleep durations,” says Dr. Namon.
CFS is a chronic (long-lasting) condition that makes people feel very tired and weak. They can also have headaches, dizziness, or other physical symptoms. Sometimes they have emotional symptoms too, like anger or sadness. Different people with CFS can have different symptoms.
As a result, their brains secrete melatonin (a hormone our bodies produce to spur sleep) later in the day. While it might feel normal to an adult to go to bed at 10 p.m., teens usually don't get sleepy until a couple hours later, and naturally wake up later in the morning.
Postural orthostatic tachycardia syndrome that is relevant to adolescents is “a chronic clinical condition characterized by chronic fatigue (and/or nausea and/or dizziness and/or pain) and intermittent intolerance of upright positions associated with postural tachycardia of greater than 40 beats per minute.”
So how much sleep is enough? According to Johns Hopkins pediatrician Michael Crocetti, M.D., M.P.H. , teens need 9 to 9½ hours of sleep per night—that's an hour or so more than they needed at age 10. Why? “Teenagers are going through a second developmental stage of cognitive maturation,” explains Crocetti.
The 10-3-2-1-0 rule is a popular sleep hygiene guideline that creates a countdown for winding down before bed, advising: 10 hours without caffeine, 3 hours without big meals or alcohol, 2 hours without work or stressful activities, 1 hour without screens (phones, TV, computers), and aiming for 0 snoozes in the morning, promoting better sleep quality by reducing stimulants and preparing the body and mind for rest.
Hypersomnia is excessive sleepiness. There are many causes of excessive sleepiness, including insufficient or inadequate sleep, sleep disorders, medications and medical or psychiatric illnesses. The characteristics of hypersomnia vary from one person to the next depending on age, lifestyle and underlying causes.
There are social, biological, and emotional reasons why teens tend to stay in bed all day. In some cases, anxiety or depression may be the underlying cause. Lifestyle changes can motivate a teen to get out of bed in the morning and start their day.
Einstein slept nearly 10 hours a day. He was known to be a firm believer in the importance of a good night's sleep, often aiming for around 10 hours of rest. However, his approach to sleep was somewhat unconventional.
Featured Expert: Philip (Phil) R. Fischer, M.D. Among adolescents, complaints regarding fatigue are relatively common and it's been assumed to be associated with the hormonal changes of puberty, the various social conflicts common in adolescence and a variety of educational expectations.
Once primary medical conditions have been excluded a common factor contributing to unexplained, chronic fatigue is physical and cognitive deconditioning; not going to school, not being on a regular schedule, sleeping too much, decreasing the amount of physical activity or not getting any physical activity.
Teenager's circadian rhythms – the cycle of sleep and wakefulness – typically begin two hours after adults. Neuroscientists say they are biologically predisposed to go to sleep around midnight and not feel fully awake and engaged until between 9am and 10am.
Parents can consider these 4 key factors to help their children and teens wake up in the morning:
Teens may experience fatigue for several reasons: Studying for school and/or being involved in extracurricular activities. Having an outside job in addition to school, resulting in extra stress. Having an undiagnosed mental health disorder.
Each day, aim to include the following: 2-3 portions of protein e.g., meat, fish, eggs, beans, pulses. 3-4 portions of starchy foods e.g., bread, rice, potatoes, pasta. 5 portions of fruit and vegetables.
Fatigue red flags signal potentially serious issues beyond normal tiredness, including unexplained weight loss, persistent fever, night sweats, shortness of breath, chest pain, severe headaches, confusion, or new neurological/joint problems alongside exhaustion. Other signs include fatigue worsening with activity, significant cognitive/mood changes, or lack of energy despite rest, suggesting conditions like infection, autoimmune disease, heart problems, cancer, or mental health issues, warranting prompt medical evaluation.
The 3-2-1 sleep rule is a simple wind-down routine: stop eating and drinking alcohol 3 hours before bed, stop working/mentally stimulating activities 2 hours before, and turn off screens (phones, TVs) 1 hour before sleep, helping you transition to rest by reducing stimulants and preparing your mind and body. It's often part of a larger 10-3-2-1-0 rule, which also adds no caffeine 10 hours prior and no hitting snooze (0) in the morning.
The koala is the animal that sleeps approximately 90% of the day (20-22 hours), a necessity due to its low-energy eucalyptus diet requiring intensive digestion, making it the ultimate champion of sleep in the animal kingdom, followed closely by sloths and bats.