Edit: (Credit: FNSUITE GHOST)
Unlike the first Escapists game, your stats don't decrease over time.
This can be done in the libary of any prison.
Here you have to walk to the bookcase and press
, then you play a mini-game where you have to keep the red bar between the lines by tapping
To get energy back fast you can consume food items, lay on a bed, get a shower or sit in a chair.
Once you have 100 intellect the achievement will pop.