Normal physical working capacity in prepubertal children with type 1 diabetes compared with healthy controls

Exercise testing has become a valuable help for the physician to examine the influence of recommended exercise training on physical fitness. However, the question as to how diabetic prepubertal children differ from their non-diabetic peers in their performance capacity has only partial and sometimes conflicting answers in the literature.

The aim of the current study was thus to evaluate aerobic fitness during an incremental submaximal test (measure of the Physical Working Capacity 170 (PWC170)) in 17 well-controlled prepubertal insulin-dependent diabetic boys aged 8.5-13 y. Eighteen healthy prepubertal boys matched for age, body size and physical activity served as controls. Part of the method was to check capillary blood glucose level in the diabetic patients and in nine of the healthy subjects throughout the exercise.

From this experiment it appeared that the level of physical fitness was similar in diabetic and healthy boys (PWC170 2.28+/-0.09 vs 2.37+/-0.13 W x kg(-1)). While glucose homeostasis was well maintained in the healthy group, diabetic children showed a marked fall in blood glucose during the exercise. In addition, the PWC170 level correlated significantly with the estimate of energy expenditure attributed to vigorous activities in the diabetic boys.

By studying the responses to incremental exercise there is growing evidence that normal physical fitness is preserved in diabetic prepubertal boys given appropriate involvement in physical activity.