Any exercise can help us control our diabetes. But when we get 45 minutes each of aerobic exercise and resistance training for just three days a week, we can reduce our A1C a lot. In fact, this combination works about as well as any prescription drug can.

People with diabetes who worked out half the time on a treadmill or bicycle ergometer -- the aerobic exercise in a recent study -- and lifted weights -- the resistance training -- saw their A1C levels drop almost 1 percent in a 22-week...