[koonsolo]

I'm doing the same thing, but only walk in the afternoon about 1 hour. It makes a difference indeed. Reading, typing and using the mouse is not as difficult as you would think.

For hard problems I also need to sit down (that's why I do it in the afternoon).

[Auracle]

I'd recommend you try to do some mental work when walking. I've found that (over at least a couple of years!) it's a skill that I've developed.