Ezra Klein wants to know why his naps don’t end well.
When I nap, there’s at least a 50-50 chance that I’ll wake up feeling groggy and awful. Whatever cognitive benefits naps offer, they’re vastly outweighed by the period of time in which I’m useless and unhappy and desperate to go back to sleep. And it’s not as if I’m bad at waking up in general: So far as the morning goes, my experience is that I’m better and quicker at waking up than most. So what gives?
What gives is that Klein’s naps are not the right length. And that doesn’t mean they’re too short. They are more than likely too long. For most people optimal nap length is less than 30 minutes (for me it is 20). The trick is to enter the first few lighter stages of sleep and then exit before experiencing the deeper ones. Going deep risks sleep inertia, that horrible, groggy feeling to which Klein refers.
Now, I’m not a sleep scientist so take all of the above with a grain of salt. (One might do better to consult the folks over at NY Times’ All-Nighters.) However, from 9th grade biology (when I wrote a report on the subject) to fatherhood (when I read many books on it) I’ve had a decades-long interest in sleep. I trained myself to power nap in high school thinking it’d be handy in college and beyond (correct I was). I’ve fought occasional battles with insomnia which have motivated me to contemplate sleep and why it is necessary, yet sometimes elusive.
One thing I learned in my amateur study of the subject is that the body has several different systems that regulate sleep. They’re quasi-independent and can get out of phase. They’re particularly apt to do so when you wake up at the “wrong time,” like from a deep sleep phase. Part of you is still asleep even though you seem awake. Your brain remains in a zombie-like netherworld until the systems re-sync hours later. That’s why you can be a morning person who fails at naps. Consider a shorter one. Sleep on it, literally.