Does hypoglycaemic avoidance behaviour contribute to increased HbA1c levels in physically active people with type 1 diabetes?

The aim of this study was to assess the relationship between glycaemic control (HbA1c), self-reported vigorous activity, aerobic capacity and hypoglycaemic avoidance behaviour in people with type 1 diabetes. We studied 50 patients with type 1 diabetes, attending a routine diabetic clinic (30 male, mean age 36 years, mean duration of diabetes 18 years, mean HbA1c 9.1%), Aerobic fitness was assessed using a multistage sub-maximal 20cm step test (Chester Step Test) and self-reported physical activity, exercise related hypoglycaemia and hypoglycaemic avoidance behaviour was assessed using a simple 'in-house' questionnaire. Thirty patients (60%) reported participating in regular vigorous physical activity (sport or gym session >1 hour/week) and glycaemic control was significantly worse in this group compared to those who did not report vigorous activity on a regular basis (HbA1c 9.5% vs 8.5%, p<0.02). Of the vigorously active group, 83% reported taking some action to prevent hypoglycaemia during physical activity compared to 70% of the group who were not vigorously active. Significantly more patients in the vigorously active group reported purposely aiming for higher than normal blood glucose levels during activity than those who were not vigorously active (8 vs 0, p<0.03). In this study, regular vigorous physical activity was associated with poorer diabetic control which may be due to hypoglycaemic avoidance behaviour. Health care professionals should be trained in the management of exercise in type 1 diabetes