Before physical exercise of medium length, that is, less than one hour, the diabetic should consume rapidly assimilable glucides in the form of fruit juice, honey or dextrose tablets. The diabetic should never go more than two hours without eating. In the case of vigorous physical activity for a long period, one should reduce the insulin dosage before the exercise. Such a diminished dose would be 10 to 30 percent of the normal dosage, and would vary greatly from one person to the other. The dosage should be evaluated by the attending physician.
Exercise increases significantly the metabolism of the muscles involved.
If insulin is injected into a muscular zone where being greatly exercised, it will be quickly absorbed. To favor a more gradual absorption, it can be injected at the level of the abdomen. In healthy persons, vigorous physical activity increases greater sensitivity and absorption which manifests even several hours after the exercise. This phenomena is found also among insulin-dependent persons. Consequently, such a person should never sleep down after a vigorous physical activity without having taken a good meal, because of the risk of delayed hypoglycemia which can manifest several hours later.