Exercise can help a person to lose weight, control their blood sugar level and lower their risk of heart disease. Exercise changes the way your body reacts to insulin. Regular exercise makes the body more sensitive to insulin. This may result in post-exercise hypoglycemia. As a result, you should check your blood sugar level before and after exercising. Diabetics should consult their doctor about the right sort of exercise program for them, as well as what their blood sugar level should be before and after exercising.