The effect of exercise in IDDM and NIDDM stems from the fact that exercising muscles increase their uptake of glucose 10 to 20 times, depending upon the duration and intensity. High intensity exercise reduces blood glucose and fatty acids are used for energy.
Exercise training enhances the action of drugs and increases insulin sensitivity. If the patient is obese, the development of such sensitivity takes a longer time. Blood sugar must be fairly under control before this is begun.
Vigorous exercise training helps normalise blood sugar, either alone or in combination with dietary modification and drugs. For type I diabetics, regular exercise is important. This improves cardiac function and lowers excess lipids. Individual monitoring of the response to exercise is important.
If exercise sessions are intense, it is advisable to decrease insulin dosage and raise carbohydrate content. If any complication is present, like peripheral neuropathy, irritative exercises like jogging which can cause foot damage should be avoided as the patient cannot feel the pain due to the nerves being damaged by excess blood sugar.
Heavy meals should be eaten one to two hours before strenuous physical activity. This avoids the coincidence of meal and insulin effect. If the patient has any other existing complications like retinopathy or renal disease, he or she should avoid strenuous exertion to prevent rise in systolic blood pressure which can damage the weakened arteries.