Posted by: notdeaddinosaur | October 24, 2010

Puberty’s End

I heard a 23-year-old woman complain:

I must be getting old when 11:00 at night is late.

It got me thinking. It turns out that the explanation for why teens are natural night owls has recently been elucidated. They can’t help it; they just don’t get tired until way later in the evening. Then, of course, their bodies want to stay asleep well into the next morning in order to feel sufficiently rested. Since most of them are stuck with the artificial structure of school hours, they’re screwed — and condemned to suffer constant fatigue from cumulative sleep deprivation.

Old news.

Then I started wondering about the back end of this phenomenon. Even though our American “youth culture” attributes great coolness to late-night happenings, since this pubertal sleep shift is biological, there must come a point at which their pineal glands go back to releasing melatonin at a more reasonable hour. Does ten years sound about right? I remember not being nearly as enamored of the “all-nighter” by the time medical school rolled around, as opposed to college, where staying up all night was a regular occurrence. Certainly by residency (ages 26 to 30) it was a killer.

Anecdotally, I’ve noticed several other physical phenomena of puberty that simmer down by the early 20’s. Acne often lessens; menses become more regular, with less discomfort; body odor diminishes. Although the definition of “adulthood” is primarily cultural (including discussions of extended adolescence these days), there remain certain biological realities. The onset of puberty has been extensively researched; the end of the process much less documented. I think it would make for an interesting field of study.

As for the 23-year-old who’s worried about “getting old”, all I can say is, “You’re not getting older; you’re getting better!” You’ll just need to get used to going to bed at a decent hour.



  1. I have to fish through my blog for this, but if I remember correctly it may be as late as 30 when the system goes back to normal (a little earlier for women than men). I guess one can search my blog for “adolescent+sleep” as I have written a lot of posts about this.

  2. I’ve gotten use to going to bed at a “decent hour”. In fact, I actually like it. It’s when I hear my school friends (who are 2-4 yrs younger than I) talk about going to bed at 3 a.m. or getting only 4 hours of sleep and yet they’re still quite functional that I feel “old”.

  3. My husband and I are both like minded old souls who go to bed at 9 and have been doing so since we got together in our early 20s… gives us more together and alone time and makes waking up to go mountain biking the next day so much easier!

  4. […] Puberty’s End […]

  5. Nah, it means you have to get up at a decent hour and GO TO WORK. It’s called being a grown-up.

  6. Please tell me it will be well before 30 when these kids get their biological clocks set right and start keeping some normal hours. I have a 19 year old who sleeps all day, literally, and is up all night running around doing God knows what and driving me crazy. He can’t get up early enough to keep an employment interview let along actually hold down a job. I have this fear that at age 35 he will be overweight and living in my basement spending his days watching television and playing on the internet.

  7. It goes gradually back…and the corporate world forces them to get up early even if their bodies are still not ready for that.

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