When it comes to warding off diabetes, there are few prescriptions as powerful as aerobic exercise. In one study, men reduced their risk of diabetes by an average of 6 percent for every 500 calories a week they burned in aerobic exercise [source: Bobalik]. With just 30 minutes of breaststroke swimming three times per week, you could burn 900 calories -- reducing your risk of contracting type 2 diabetes by over 10 percent. A study that focused on women also suggested the same benefits for the fairer sex: Vigorous exercise just once a week (like the kind derived from a robust swimming session) lowered their risk of contracting type 2 diabetes by 16 percent over inactive women [source: Bobalik].
And, if you already have type 1 diabetes, the aerobic benefits of swimming can be particularly helpful, as this type of exercise can increase insulin sensitivity [source: University of Maryland].
According to the American Diabetes Association, diabetics should get 150 minutes per week, spread across at least three days per week, of moderate-intensity physical activity like swimming to aid glycemic control.