Circadian
Circadian rhythm is your body's 24-hour internal clock, shaping sleep timing, alertness, and hormones — essays, science, and field notes on living with it.
How to Reset Your Circadian Rhythm — and What That Has to Do With Your Skin
Walk down the skincare aisle and you will eventually meet the phrase "night repair." The idea is that your skin, like a nocturnal janitorial crew, does its real work while you sleep — and that if you…
Diagnosing Shift Work Disorder: What a Sleep Study Can and Can't Tell You
You have been sleeping badly since you switched to nights. A friend, trying to help, says the words everyone says: you should get a sleep study.
Why Does Daylight Saving Time Wreck You for a Week? The Honest Answer
Every March, some version of this question arrives around Tuesday: why does losing a single hour feel like jet lag without the trip? You went to bed at the usual time, more or less.
Postprandial Somnolence: Why Lunch Makes You Sleepy, in the Order It Actually Happens
You finish lunch, sit back down at your desk, and within forty minutes the screen starts to blur. You've probably been told why: blood rushes from your brain to your gut to handle the meal, and your…
Can You Actually Adapt to Shift Work? I Spent Three Rotations Trying to Find Out
Here is the question I actually wanted answered, the one I could never get a straight reply to from a manager or a forum: does your body ever adapt to shift work, or do you spend the whole time just…
Sleep Deprivation in Teenagers Isn't a Discipline Problem. It's a Clock Problem.
Your tired teenager is probably not lazy, and probably not staying up out of defiance. The most likely explanation is duller and more biological than either: their internal clock has shifted later…