The practical experience of excerise and diabetes

ABSTRACT

Most patients with diabetes can safely engage in recreational and work related physical activity. Sedentary patients with a long duration of diabetes probably should have an exercise stress electrocardiogram prior to initiating an exercise programme. Pre-exercise evaluation should also include a careful eye, neurological, and peripheral vascular examination. The usual recommendation for a monitoring programme in patients with diabetes are given in the following table (table in journal). These recommendations are not dissimilar to those for other patient populations at high risk for vascular disease. The duration and intensity of exercise should be adequate to induce some degree of glycogen depletion. Exercise at intensities below 30 - 40 percent VO2max has little effect on subsequent glucose disposal. Aerobic exercise are generally preferred although resistance exercise can result in significant improvement in glucose, lipid and blood pressure levels. In addition, the increase muscle mass resulting from resistance training may be particularly beneficial for older patients and as an aid to weight maintenance. Potential problems with intense resistance exercise include an increase risk of musculoskeletal injuries an large swings in systolic blood pressure with possible cardiac and/or microvascular damage. A rough guidelines would be to utilize a resistance such that the patient can comfortably perform 15 repetitions in a given exercise. During training three set of 8 - 12 receptions of each exercise can be done. This level of training results in only modest elevation of blood pressure, has been shown to be safe exercise for older patients, and results in a significant increase in muscle mass. Many sedentary patients with type 2 diabetes have an unusually low VO2max. Initiating exercise regimens at too high an intensity is a common error in these patients. Estimate based on submaximal exercise testing using standard nomograms are often used to estimate maximal heart rate and oxygent comsumption and to prescribe exercise regimens. Prescriptions based on such data may overestimate the fitness of diabetic subjects and should be used with caution. The metabolic effects of exercise on subsequent glucose disposal are not negated by brief rest periods (<90 seconds) during the training sessions. These rest periods may make exercise more acceptable, particularly for older or unconditioned populations.(AU)