It sure sounds like a lot of exercise to me! I try to either swim a mile, or walk three to four miles, four or five days a week. I have found that sometimes pushing it too hard -- walking too far and too fast -- actually slows my weight loss down. I'm not sure why that is. I think it may be because I get hungrier when I do more than my accustomed amount of exercise and I eat more calories than I need to compensate for the extra exercise.