My doctor told me that I should either walk or ride a bicycle. Since I spend most of my day at work on my feet walking was not an option for me. I chose the bicycle route. When I first started riding a year ago February I could hardly make it around the block, I was so out of shape! I now have no problems with riding for as long or far as I want. Yesterday I rode a 10.5 mile ride in just under an hour and could have done more if I had time. Maybe ask your Dr. if riding a bicycle could replace walking, it worked for me!