The Lever That Actually Moves It

Most sleep advice fixates on bedtime — go to bed earlier, wind down sooner, set a bedtime alarm. But for the circadian rhythm specifically, wake-up time is the bigger lever. A consistent time you get out of bed anchors the whole clock more reliably than a consistent time you try to fall asleep.

Part of the reason is that wake time is easier to actually control. You can decide when an alarm goes off; you can't fully decide when you fall asleep, especially if the clock's timing is already a bit off. Anchoring the piece you can control turns out to pull the rest of the system along with it.

So if only one thing about this level sticks, it's this: pick a wake-up time and hold it most days, even on days sleep didn't go well the night before. That single habit does more for a stable rhythm than an elaborate bedtime routine attached to a wake time that moves around all week.

According to this lesson, what's the bigger lever for a stable circadian rhythm — bedtime or wake-up time?

Wake-up time is easier to actually control than falling asleep because you can decide when an ____ goes off.

This lesson argues that bedtime is a bigger lever for the circadian rhythm than wake-up time.