What are subtle exercises I can do?

My doctor says that I should be exercising up t four hours a day- but not overworking all at once at the gym, small subtle exercises. With proper breathing too. I dont understand, I am very weak and exercise is definitely the mort important thing for me right now, but it is so hard that it gets discouraging. And strengthening and stretching arent the same as cardio... I just hate walking because it is so hard and tiring. Any suggestions of small exercises to get me going and build strength without getting so discouraged?? I think he just wants my muscles to keep moving while I am in the healing process. Tweet