How many hours of sleep do teens need? If you base your answer on observations of teens you know personally, you might choose a number anywhere between 90 minutes and 16 hours per day. Oh, and maybe a catch-up session of 22 hours or so on the weekend. In reality, teens do need a certain amount of sleep for optimal physical and mental health. Their needs differ from those of younger kids and adults who are even a year or two older.

And the importance of sleep for teens can’t be overestimated, even though that age group tends to shrug it off. Teens may not say “sleep is for the weak” out loud, but the attitude is fairly common. So is the viewpoint that sleeping for long bouts is not only acceptable but sort of a competitive hobby. As the parent, you must work with these views and the limits of your relationship with your child. But the benefits are worth the hassle of working together to decide how much sleep your teenager should get. Here’s how to strike a balance between being a helicopter parent or the enabler of a sleep-deprived teen zombie:

Why teens push bedtime back

It’s not only rebellion that’s at work when a teenager’s bedtime seems to get a little later each night. The pattern shows an influence of biology known as “sleep phase delay.” In adolescence, their growing bodies make a teen want to wake up and go to sleep later. Once a body reaches puberty, it starts signaling it’s time to sleep at 10 p.m. or 11 p.m., not 8 p.m. like it did in adolescence. That becomes a problem because teens also need about 9 hours of sleep per night. If they go to bed later and get enough sleep, they’ll also wake up too late for school, work or family activities.

Along with this natural tendency to delay bedtime, teens can also have a busy school and social life that causes them to occasionally stay up really late. This can mess up the internal clock that tells your teen it’s time to sleep. In addition, not getting quality sleep can make your teen tired at the wrong times of the day. Sleep deprivation becomes a vicious cycle since teenagers tend to try to sleep in on weekends which only disturbs their natural circadian rhythms more.

All that might be okay if it wasn’t so damaging for teenagers to try to get along without ample sleep. Sleep deprivation can make the challenging teen years that much harder. Just a few of the detriments of inconsistent or poor quality sleep include irritability, foggy thinking, increased feelings of depression and a greater risk of obesity or getting in a work-related or auto accident.

How much sleep should a teenager get?

Experts recommend teenagers sleep 8 to 10 hours each day. This amount of quality sleep helps teenagers function well, think more productively and even eat better. This amount also helps teenagers cope better with the stresses of the hectic, sometimes mean-spirited world they live in. If you’re thinking, “There’s no way my kid is getting that much sleep!” you’re probably right. A Journal of Adolescent Health study showed just 8 percent of teens in the U.S. sleeping that 8 to 10 hours. Much more common was severe sleep-deprivation, meaning an average of six hours of sleep or less on school nights. Fifty-nine percent of teens are in that category.

Is yours? If you pay attention to your teen’s schedule, you probably have a pretty good idea whether she’s sleeping enough to avoid the many problems with sleep deprivation. Even if you think you know your teenager’s sleep-wake cycle details, though, you might want to pay attention to behaviors that indicate your teen isn’t sleeping well. One sign is when a teen falls asleep in class, in the car on the way to school, at dinner or in church or during family activities. Another is when your teen simply hates to wake up in the morning or is difficult to drag out of bed. Teens who seem depressed might have poor sleep as a root cause, too.

Help your teenager sleep better

Like adults, teens will really benefit if they practice better “sleep hygiene.” This term has nothing to do with germs and everything to do with developing the habits that will help a teen sleep better. Never doubt that you can be a positive influence in this area. The best scenario is when you’ve started encouraging sleep hygiene when your child is younger. But even for teens, it may not be too late. “There’s pretty good evidence that parental help with limit-setting around bedtimes and study times and media is helpful,” Dr. Mary Carskadon, director of chronobiology and sleep research at Bradley Hospital in Providence, Rhode Island told the Child Mind Institute.

Consider helping your teenager establish some or all of these habits:

-Try to go to bed at the same time and wake at the same time each day, even on weekends. Sure, this tactic won’t always work, but if you can keep a consistent schedule, your teen’s internal body clock will begin to run quite smoothly.

-Eliminate caffeine after mid-afternoon and snacks after about 6:30 p.m. Otherwise, the mere process of digestion can interrupt both sleep and the signals that it’s time to go to sleep.

-Stop watching television, texting or talking on the phone from bed. You want your teen to associate going to bed with going to sleep.

Maybe most importantly, start focusing on your own sleep patterns and do what you can to improve them. While teens may seem to ignore you entirely, there’s a good chance you can influence their sleep habits simply by being a good role model.