Instructed to patient exercise is good for those with diabetes. Walking, you can even get exercise when you clean house or work in your garden. Exercise is especially good for people with diabetes because exercise helps keep weight down. Exercise helps insulin work better to lower blood sugar, exercise is good for your heart and lungs. Exercise after eating, not before, test your blood sugar before, during, and after exercising. Don't exercise when your blood sugar is over 240, avoid exercise right before you go to sleep, because it could cause low blood sugar during the night.