Type I diabetes is characterized by inadequate pancreatic insulin secretion, and the consequent need for replacement of the hormone daily via subcutaneous injections. In the absence of insulin, glucose transport into cells is hindered, causing a progressive hyperglycemia and ketoacidosis. Individuals with type II diabetes (or adult onset) are usually older than 45 years and normally undergo insulin resistance rather than a quantitative insufficiency. Typically, oral medications and weight loss are able to control hyperglycemia in type II diabetes without insulin application.
The main objective in the daily management of patients with Type I diabetes is to maintain a state of euglicemia – preventing hyper-and hypoglycemia – balancing the influences of diet, exercise, and insulin on blood glucose levels. But ultimately, morbidity and mortality of this disease are associated with vascular and neurological complications that normally occur in clinical form in young adulthood, and include :
* A generalized thickening of the basement membranes of capillaries (microangiopathy) that affects various organs, with greater prominence of the eye (diabetic retinopathy) and kidneys (diabetic nephropathy).
* An accelerated atherosclerotic vascular disease (macroangiopathy), presenting as early disease of the coronary arteries and heart attack.
* A peripheral neuropathy affecting sensory function, motor, and autonomic.
It is clear the relationship between insulin deficiency and these chronic complications of diabetes. More specifically, it is uncertain whether tight control of sugar levels in the blood favorably influence the natural course of the neurovascular manifestations of diabetes (DCCT Research Group, 1988). Still, the fact to avoid fluctuations in blood glucose concentrations outside the normal range, is considered an important goal for most physicians caring for these patients.
The observation made by McMillan (1979) that physical activity has been recommended for the treatment of diabetes mellitus since “time immemorial” is probably not an exaggeration. Historians have marked the relationship between exercise and diabetes as early as 600 BC, when the Indian physician Sushruta prescribed physical activity for patients with this disease. Among his successors, who were also convinced of the benefits of regular exercise on diabetes, were the prominent Roman doctor Celsus and the Chinese Yuan-Fang Chao, who practiced during the Sui Dynasty in 600 AD. What these doctors noticed was a better sense of wellbeing in patients with diabetes, and the subsequent demonstration that physical activity could decrease blood glucose levels in this disease, suggested another reason to include exercise in their treatment. When Lawrence (1926) found that physical activity improved the hypoglycaemic effect of insulin administered, regular exercise has become a key element in the triad in the treatment of diabetes: insulin, exercise, and diet (Joslin, 1959).
The enthusiasm for exercise was based on the premise that the effects of glucose decreased by physical activity would improve metabolic control, benefiting the quality of life of patients with diabetes. A scientific assessment of the relationship between exercise and diabetes, made in the past two decades has supported only a part of such hopes, but in the overall analysis, regular exercise continues to play an important role in the health of these children and adolescents.
In addition to any specific effect of exercise on diabetes, children with this disease deserve to enjoy, like young non-diabetics, the same social and health benefits of regular physical activity. Still, fear of the metabolic changes during exercise which could precipitate a hypo-or hyperglycemia causes many children with diabetes avoid physical activity. Physicians have the opportunity to contribute to the welfare of these patients by helping them to adapt their treatment so as to allow safe participation in sports events.