Need Advide: How to stay focused?

Hey everyone! I've noticed that after a few hours of coding, my brain just hits a wall. I start rereading the same code, debugging takes forever, and I can't think as clearly. Stepping away usually helps, but it's frustrating.

Can anyone relate? What do you do to stay mentally sharp during long coding sessions? Do you take any supplements, chew gum, drink coffee, or have any routines that actually work?