I could feel your peace!
I used to walk outdoors too and loved it, going about 4 miles each day. Now that I have reached an advanced age, I resort to exercise each day on my mini trampoline. It is an exercise promoted by the Air Force. I have been doing this for the last two years, every day for at least 25-40 minutes. It really gets my heart rate up to maximum aerobic rate and my feet do not have to raise more than an inch off the surface, much safer for me than walking on uneven terrain. Good post!