SACHA PFEIFFER, HOST:
Most of the U.S. switches from daylight saving to standard time tonight. That means most of us will get an extra hour of sleep, and that's especially good news for teenagers. More than 3 out of 4 high school students don't sleep enough, according to the CDC. So as Sarah Boden reports, most adolescents need help getting more rest.
SARAH BODEN, BYLINE: It's 5:30 a.m, and Pittsburgh-area high school sophomore Louisa Patel is about to leave for rowing practice.
LOUISA PATEL: It's nice to be on the water. Like, when the sun comes up and all that, it's really pretty.
BODEN: As you can hear in Louisa's voice, she's still waking up. While her dad drives us to practice, Louisa tells me she tries to be in bed at 9 p.m., which is rare for a teenager.
LOUISA: Most of my friends, they have, like, really messed up sleep schedules.
BODEN: Do you feel like your sleep schedule is pretty healthy?
LOUISA: Yeah, according to what my dad says.
BODEN: Louisa's dad is a sleep medicine physician at the University of Pittsburgh Medical Center. Dr. Sanjay Patel says he's doing the best he can to make sure that Louisa and her twin sister get good rest.
SANJAY PATEL: It's still affecting them. You still see how tired they are in the morning.
BODEN: One sleep rule in the Patel household is no sleeping in on the weekend. An extra hour or so is fine, but Louisa is up before 8 a.m. That's the right call, says Stephanie Crowley, a chronobologist at Rush University in Chicago.
STEPHANIE CROWLEY: If teens do sleep in over the weekend, they kind of jet lag themselves. Their clock will shift about 45 minutes, 50 minutes, just over those two days.
BODEN: But it's not as simple as a strict bedtime and wake-up time. More than any other age group, teens have to fight to stay on a schedule that doesn't match their biology. One reason is our internal 24-hour clock, the circadian clock.
CROWLEY: The internal clock, the circadian clock, we can kind of think about as the conductor of an orchestra of many clocks throughout the body.
BODEN: At the start of puberty, this orchestra of clocks decides, hey, I want to stay up really late. And then there's another biological mechanism that tracks how long you've been awake and tells your body when to go to bed. It's called the homeostatic sleep drive.
CROWLEY: You can think about it as a pressure cooker, as well. So that pressure for sleep to begin just kind of grows much more slowly in the more mature adolescent.
BODEN: On top of the biology, high schoolers have packed schedules. This also steals their sleep. After school, there are extracurriculars, part-time jobs, homework.
MARY CARSKADON: And teens will always say, it's homework. There's too much homework. I - actually, I believe them.
BODEN: Mary Carskadon is a sleep researcher at Brown University. She says communities could help teens by starting school later and putting limits on how late evening activities can go for. And teens would be better off if the U.S. stayed on standard time the entire year. The schedule has darker evenings and brighter mornings. That morning light helps get the circadian clock on schedule.
CARSKADON: And if you move school start time later and you're on standard time in the winter, there's a bigger opportunity for the adolescents on their bus ride to school to get that morning daylight.
BODEN: In the meantime, if you're a teen - or really anyone - tomorrow's change to standard time is a chance to jump-start to a better schedule. Say you usually go to bed at midnight. Maybe tomorrow, turn off the lights at 11. It probably will still feel like midnight to your body, but you'll wake up with an extra hour of rest. For NPR News, I'm Sarah Boden.
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