Functional adaptation to rigorous training and exercise in diabetic and nondiabetic adolescents

Functional adaptation to training and exercise was studied in six diabetic and six nondiabetic boys, 15–19 years of age. The training program consisted of 5 months' regular physical activity with stepwise increasing intensity. At the end of this period the subjects took part in a cross-country ski run, lasting for 3–4 hr and repeated on 3 consecutive days. Exercise tests were made at regular intervals with both submaximal and maximal workloads and work capacity was expressed as maximal oxygen uptake (max V o2 ). At the beginning of the study the diabetic boys had lower functional capacity than the controls, but during training the max V o2 as well as heart volume increased similarly and significantly in both groups. At submaximal workload the lactate concentration was the same among the diabetics as in nondiabetics, but at exhaustion it was somewhat lower in the former group. The caloric intake increased substantially (ca. 50%) in all subjects but during the actual work hours the carbohydrate intake was greater among the diabetics than among the controls. Glycosuria in the diabetic group was approximately unchanged during the whole study. All subjects could fulfil the work, and there were no untoward effects of exhaustion. In the diabetic group insufficient caloric supply and the concomitant risk of hypoglycemia seemed to be the most important limiting factor for prolonged heavy work, but the responses and adaptation of pulmonary and cardiovascular functions were adequate and similar in both groups. juvenile diabetes; prolonged exercise; exercise tests; maximal oxygen uptake; blood lactate; caloric intake Submitted on October 23, 1963