Our experience with teenagers is they do need more sleep. Of course you can’t generalize and blanket them all but all four of ours slept more during their teen years. In fact at times they would come home from school and take a nap. The thing to remember as a parent is that sleep restores. During teen years there is so much change happening in their bodies. Hormones are being released and they are growing physically. It’s not uncommon for some teenagers to grow six inches in a year – and some do it over a summer.
Mentally they are being challenged more than ever. This is the information age. During high school years the workload is increased at school and relationships can be intense. Emotionally they can handle more when they are not tired. Watch carefully to see if your teenager is withdrawing into sleep. It could be that sleep is a safe way of escape or avoidance. The key is to avoid judging and keep open communication. If there is a reason they need to be up earlier than normal, then make sure the expectation is spoken about ahead of time. For example, if the family is going out for the day be very clear the night before that everyone needs to be up and going in the morning. If there is no reason for them to be up then let them sleep. Some times a good sleep is precisely what is needed to restore the body and the mind.
Lastly don’t nag them into being up. Just because you are up doesn’t mean they have to be. Remember these are the same children you were trying to get to sleep twelve hours through he night just a few years before!