Do you know how long teenagers are supposed to sleep for each night?
The answer is D), 9+ hours. But most teenagers are lucky if they get 7 hours, because the math of sleeping longer just doesn't work. If they have to get up at 7:00 a.m. for school, it's unlikely they can fall asleep at 9:45 the night before (if they're even done with their homework). Adolescents are not genetically programmed to fall asleep early.
It's important to understand that sleep deprivation doesn't just make a young person tired. Really, that's almost the least of it. Sleep deprivation interferes with brain function, concentration, and decision making. It causes depression, anxiety, and worse.
Maybe you know know all that already. What can you do to help your teenager?
1. Limit their commitments. Most people think high school students need a long list of extracurricular activities to look good for colleges. This is not true, but it still leads students to take on too many activities for their own good. A better path is good grades, a deep commitment to one or two important activities, and a healthy sleep schedule that facilitates success in those endeavors.
2. Naps can help. Some people frown on naps entirely, and that's a mistake. Naps should occur as early as possible in the afternoon and last less than an hour, and there are potential contraindications too. But they should be considered.
3. Be a model. Value your own physical and emotional health, including your sleep habits, and show it! Talk about how good you feel in the morning because you got a full night's sleep.
4. Feel empowered to act. If you need to take more significant action to enforce healthy sleep habits, then (I would say) do it. That will not only help the situation in an immediate sense. It will also show your teen that you consider sleep—and therefore, their physical and emotional well-being—a big deal. It shows that you care.
This isn't an easy topic, but I hope this reading might be of some help.