Endocrine Abstracts

Exercise induces an increase in cardiac output, respiration and fuel mobilisation. Whilst the cardio-respiratory response to exercise is similar in type 1 diabetes to that seen in non-diabetic individuals, the response to mobilisation of fuel source to support exercise is impaired.

Normally when exercising changes in insulin and counterregulatory hormones secretion are made which are dependent on the type of exercise being performed. These changes facilitate an increase in liver glucose production which matches skeletal muscle glucose uptake during exercise and (see table below). A change in the secretion of these hormones is also seen post exercise to facilitate recovery and adaption to exercise. As a result of these changes, blood glucose levels remain stable before, during and after exercise.

In type 1 diabetes, the pancreas does not regulate insulin levels in response to exercise and there maybe impaired secretion of counterregulatory hormones, making normal fuel regulation difficult. Post exercise the lower levels of insulin and counterregulatory hormones can hamper recovery and adaption to exercise. This means that hypoglycaemia both during and following exercise becomes a significant risk. Furthermore, hyperglycaemia prior to and following some types of exercises can also be problematic. If changes in insulin dosage and nutritional intake are made in line with the normal expected physiological responses to the particular exercise being performed, then these deficiencies can be overcome and enable ideal glucose control to be maintained before, during and after exercise.