[grzm]

It's a bit more complicated than that. Here's an article that gives a gloss as well as links to more detailed research:

https://www.vox.com/2014/8/28/6074177/coffee-naps-caffeine-s...

I was always surprised when I found myself suddenly so sleepy after a shot of espresso in the afternoon. It was nice to find that there's science backing it up.

[Bartweiss]

Woah, thanks for this. I knew the trick, but I always assumed it was just about sleeping until the caffeine blocked out adenosine so you woke up not-tired. Interesting to see there's a deeper mechanism in play.