Exercise training in individuals with diabetic retinopathy and blindness

Limited guidelines exist for rehabilitation programs for individuals with diabetes mellitus, blindness, and associated autonomic neuropathy. Abnormalities in autonomic function have been postulated to interfere with exercise conditioning and may predispose individuals to exercise-induced hypoglycemia. Twenty-nine individuals with diabetes mellitus underwent standardized noninvasive testing for the evaluation of cardiovascular autonomic function and graded exercise before entering a rehabilitation program. Inadequate responses of heart rate to respiratory variation were observed in 28 patients, abnormal heart rate responses to postural maneuvers were seen in 23, and postural hypotension was noted in nine. Individuals with symptomatic postural hypotension were able to exercise using a stationary bicycle, but developed hypotensive episodes on walking or prolonged standing. Blood glucose consistently decreased by a mean of 76 (+/- 9) mg/dl after each exercise session, even though low levels of exercise were performed (2.9 +/- 0.2 metabolic equivalents, for 28 +/- 1 min). There was no relationship between the degree of autonomic neuropathy and the level of blood glucose fall. There was, however, a significant correlation (r = -0.59, p = 0.001) between the decrease in blood glucose level and the amount of regular insulin used in the routine morning dose. Precautions were taken to avoid hypoglycemia, and insulin and diet were adjusted accordingly to prevent severe hypoglycemic reactions.