Have you tried an espresso nap? It works great. Drink an espresso when you're feeling tired and go to sleep straight away. 15 mins later you'll be awake and alert but also rested.
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.
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.
I'm usually far more productive after taking a much needed nap than trying to drink coffee/tea and power through it.