+1 with Lisa's advice. I no longer can get my HR up with walking, but I still do it a couple of times a week. It makes my body feel good in ways that are different. Sometimes I don't have time to do anything except the 2.2 mile walk up and down my street... since it's a hill, I just walk really fast and I can now get up a sweat doing that. But other times, I walk with DH, who "complains" about walking faster than about a 3.5 mph pace (he has "delicate" feet.) This is what really stretches out my body. Since I decided I can no longer attempt to run (which I loved for weight control), which wreaked havoc on my back, I have decided to keep walking as an important part of my fitness routine. I often combine it with yoga or core work when I get back. Since I no longer belong to a gym, this is what I do on days I would have been at the gym.