Those empty receptors become chairs in a brain game of musical chairs.
Your brain begins creating adenosine again as soon as you wake up from your nap.
But the caffeine is starting to reach your brain and fill those receptors before the adenosine gets a chance to fill them again.
The 2 compounds will fight to fill up all of your brain receptors until the caffeine fully breaks down.
Once that happens, its receptors open again to all that built up and homeless adenosine suddenly grabs a chair.
This is that post-caffeine crash we’ve all experienced.
But that’s ok, because by now we’ve powered through that big project thanks to our power nap and caffeine jolt, and we can head off for some dream time.