[maxerickson]

Walking carries much of the benefit of higher intensity exercise.

It won't build aerobic capacity much, but it burns calories and is good for heart health and so on.

[mark_l_watson]

I think it helps if the first half of a walk is up hill. I live next to national forest land, and even a 20 minute walk helps because the first ten minutes is up hill so my heart rate increases. When I am hiking without friends, I move at almost a jogging speed when walking. With friends, we walk leisurely. I try to do one very long hike a week (2 to 4 hours) if my work schedule permits this. Anyway, I have read that it is distance covered that counts, that jogging 2 miles is about the same as walking two miles.

Feel free to call out bullshit here, but: I think that exercise where you are mentally calm and happy counts for a lot more than exercising when you feel tense or unhappy.