Hmm, but I wonder if not doing enough at once continuously makes focus and productivity lower, up to a point, by doing activities like alternating between work

Hmm, but I wonder if not doing enough at once continuously makes focus and productivity lower, up to a point, by doing activities like alternating between work and video games/glowing screen notification checking. I also would like to know what is the neurological basis for the painful post-exam / difficult work "hurty brain." I can only imagine what it must feel like after taking the JEE.