By Bryan Hoff, MD
Getting enough sleep improves students’ academic and athletic performance, overall health, and quality of life.
For teens, getting enough sleep isn’t just a matter of how much . . . it’s when they sleep.
Children usually need 10-11 hours of sleep; most will sleep between 8:00 pm and 6:00 am. But once kids hit puberty, two physical changes put their bodies on the late shift, making sleep-wake cycles about two hours later for teens.
First, natural secretions of nocturnal melatonin occur later in the evening, at the same time there’s a shift in teens’ circadian rhythms, or “body clock” (energy levels attuned to a 24-hour cycle) – making it natural for teens to fall asleep later. Second, the body’s “sleep drive” slows, and the pressure to fall asleep accumulates more slowly – so it takes longer for teens to fall asleep.
But teens need still 8 ½ to 9 ½ hours of sleep per night as their bodies and brains grow, and as much as 12 hours when the body (and brain) are in a growth spurt. (Most of our high school seniors get less than 8 hours. Yet 71% of parents think their teen is getting enough sleep, reports the National Sleep Foundation.) That means teens who have trouble falling asleep before 11:00 pm do best to wake at 8:00 am or later, recommends the American Academy of Pediatrics.
During the school week, school start times are the main reason students wake up when they do, says the Centers for Disease Control. “The combination of late bedtimes and early school start times results in most adolescents not getting enough sleep,” CDC reports.
CDC, the American Academy of Pediatrics, and National Sleep Foundation all recommend that high school and middle school should start at 8:30 am or later to let teens get enough sleep, during their best sleeping hours.
“Delaying school start times is an effective countermeasure to chronic sleep loss and has a wide range of potential benefits to students [in] physical and mental health, safety, and academic achievement,” states the American Academy of Pediatrics.
If school starts later, won’t students just stay up later? It seems not: A three-year study of over 9,000 high school students in Minnesota, Colorado and Wyoming found that twice as many (66%) with a late start time (8:55 am) got 8 or more hours of sleep than students with a start time of 7:30 am – only 33% of students, reports AAP.
Well-rested teens have better academic scores, lower rates of depression, less risk of obesity, fewer drowsy driving car accidents, and less risky behavior such as drinking, smoking, and using drugs.
Set a healthy sleep schedule – and encourage teens to stick with their school-night sleep regimen on weekends. Staying up (and waking up) late feels good after a rigorous week, but it makes it hard for the body to stay on track.
Bryan Hoff, MD is the medical director of Northfield Hospital’s Sleep Center. He is board-certified in Sleep Medicine by the American Board of Internal Medicine. Reach the Sleep Center at 507-646-1099.
Good sleep habits for teens
- Keep cell phones, computers and TV out of the bedroom. They stimulate the brain and make it hard to wind down
- Turn off all electronics 30-45 minutes before bedtime
- Park the cell phone for the night in a common area outside the bedroom. Need an alarm? Use a bedside clock instead of the phone
- Avoid caffeine after 5:00 pm
- Avoid large meals or exercise before bed
- Only sleeping in bed; no studying, reading, watching TV
- Keep bedroom temp below 75 degrees; warmer makes it harder to sleep