The design and evaluation of a self-management algorithm for people with type 1 diabetes performing moderate intensity exercise

Limited evidence is available to advise people with type 1 diabetes about self-management strategies for maintaining acceptable glycaemic control when exercising. A systematic review was conducted to design a self-management algorithm for moderate intensity exercise. The effectiveness was investigated regarding the attainment of acceptable glucose concentrations during and after 40 minutes of exercise at 70% VO2 max in the real-life environment. Nine individuals with type 1 diabetes (five male, four female) completed the study over a two-week period. All used a basal bolus analogue insulin regimen and exercised regularly. Participants undertook 40 minutes of moderate intensity exercise on days 1 and 8 in real-life environments, and followed the self-management algorithm. Data were collected for glucose concentrations at 10 time-points, i.e. before, during and after exercise. Analysis showed that during the whole time-period, 56% of participant episodes were in the acceptable glucose range of 4-9 mmol/L, and 39% were above 9 mmol/L. In relation to hypoglycaemic episodes, one episode occurred during exercise, and eight episodes occurred during 8-12 hours after exercise. Despite post-exercise insulin reduction, nocturnal hypoglycaemia occurred and algorithm adjustments are required regarding carbohydrate consumption at bedtime for future prevention. An addition to the current self-management algorithm would be to perform blood glucose monitoring 8-12 hours after post-exercise insulin and meal.