According to an article in The New York Times Fitness & Nutrition section, we burn more calories doing weight-bearing activities that work against gravity – such as walking or running, than we do with activities such as swimming and water aerobics. The latter are easier on the joints, however, as the article points out, “so many people can do them for longer periods, which makes up for the lower caloric burn.”
Well, I’m no proponent of counting calories, but I suppose that for anyone trying to reach a healthier weight, the point that this article makes could be a good one to keep in mind. Swimming for an hour seems to burn more calories than jogging for twenty minutes, so you may want to start going to the pool for your exercise. You could also just combine the best of both worlds and try jogging in water! Or, if you’re looking for a more low-key way to burn calories, you could try ai chi; Marlene teaches an ai chi community class at the Roosevelt Warm Springs Institute, which appeals to students who are suffering from arthritis and fibromyalgia.