[mcgoo]

This. For me, exercise is the gift that keeps giving.

Caffeine works for a couple of days and then becomes a requirement. Any ongoing benefit is difficult to discern.

There are other things that make a huge difference to productivity for me :- - have a plan for the day - make sure to work on stuff that is actually important - look back at the day and see where time was wasted or I went off track and think about how to do better next time - stop working at a fixed time (with a little leeway if I am really in the zone and enjoying it.) This leaves me excited to get to work in the morning. Scheherazade effect :-)