Walking question

[thistlechaser]

After much thought, I have decided on a plan. Since you can't really increase the number of calories walking burns off, the only thing you can do is increase the time spent walking. Problem is, I don't have a multi-hour chunk of time I'd like to give up... but I can handle putting an hour towards it here and there. An hour in the morning, an hour at lunch, an hour at night/after work. That's do-able.

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.)

Thanks!