The changes that happen during puberty go way beyond the bodily transformations we all know about. The adolescent brain changes too. And brain changes relate to sleep changes. How puberty affects sleep has little to do with how late the teenager stays up. It has more to do with changes that are happening in her brain.
How Puberty Affects Sleep is Deeper Than Skin
No, teens are not moodier because they are not sleeping well. And they’re not sleeping more because they are moody. The moodiness and the changes in sleep are separate by-products of puberty. The sleepiness, however, is made worse by the unfortunate timing of school hours, a subject we will get to.
We many not remember our own sleep patterns during our teen years. But we probably started going to bed later and wake up later as well. Those of us who have teenagers, or who know one well, may have noticed this. It seems fairly universal.
We may have also noticed that the teen may be very unhappy indeed about having to wake up early for school. Many teens report being wiped out after school, especially if they play sports. It’s tempting to blame the teenager for staying up to late and causing her own sleepiness. But if you yield to that temptation you are only half-right: part of the staying up late is cultural. But part of it is biological.
Nature and Nurture
For a long time, the question simply had not been studied. Teenagers tended to stay up later. We assumed we did this because, well, they are teenagers. But since the 1990’s there have been a number of studies of how puberty affects sleep in large groups of teenagers.
For example, Mary Carskadon and her colleagues at Brown University in Rhode Island, USA, did a study of fourth to sixth graders in public school and came up with some interesting findings. They found that later bedtimes and pubertal stage were closely related to one another. In other words, as the children went through puberty, they simply went to bed later, even after controlling for age, birth order, and other factors.
Laberge, et al, in a study of Quebecois teenagers, also found that adolescents were going to bed later. The investigators also found that these kids were sleeping less, most likely because of having to wake up for school. In fact the study showed that teenagers “slept in” on weekends when there was no school. “You need a study to tell me my kids sleeps late on Saturday morning?” you may ask. Sometimes you do.
Israeli Teens Do it Too
A two-year study out of Tel Aviv followed kids as they passed through puberty and measured their sleep. They found that teen sleep-wake patterns reorganize during puberty. Just as with the Rhode Island and Quebec study, the Israeli study showed later bedtimes, less overall sleep, and increased daytime sleepiness. Investigators also looked at tolerance for sleep deprivation and found that the teenagers actually tolerate the loss of sleep better than younger children do.
Here we have three studies from different parts of the world which come up with remarkably similar results. Is there something to this relationship between puberty and sleep?
What if It’s True?
No. It’s it’s not just interesting, it’s important. Later sleep times in puberty are often a bad fit for the school schedule that we impose on teenagers. Teens already stay up later for a variety of reasons, some of which relate to 21st century culture. Now that we know that the sleep-wake cycle shifts later in the day for teens, we ought to consider how we can better help them get through the day without getting exhausted.
This is where a sleep consultant can help you. If you have a teen and you’re struggling with a sleep problem, I can help. Please feel free to contact me.