The question is, after I hit an hour once a day, how do you go about duplicating it? Think a person would need to build up slowly again (same speed as you would if you were doing one two-hour chunk instead of two one-hour chunks) or could you just jump right in and walk for the full hour a second time? Or is there no answer and you have to do what your body wants?
(This is a longer term goal, mind you. I need to hit an hour first, then deal with more.)