The reasons behind this great coffee and nap romance are timing and chemistry.
As we go through our day, our brain activity produces a hormone called adenosine.
Adenosine induces drowsiness and creates that brain-tired feeling that we feel at night and during that slump.
And the only thing that reduces the adenosine in your brain is sleep.
So as it builds up in our system, our brain essentially begs us for a nap.