My problem is that I don't know how to rate the exercise that I do because I don't walk at 2 or three miles per hour but still I am exercising. My heart rate is elavated quicker than those that are healthy. To most people I will just be moving but to me I am doing good exercise. My doctor tells me that walking no matter how fast is what will keep me healthy. I am thinking about getting a mini bike that can be used while sitting for legs and also can be used by the hands.