Evaluation of Factors Related to Glycemic Management in Professional Cyclists with Type 1 Diabetes over a 7-Day Stage Race

23 April 2020

Athletes with type 1 diabetes have considerable challenges when managing their blood glucose, particularly around training and competition. In this study, published in Diabetes Care, six male professional cyclists with type 1 diabetes were observed during the Tour of California. During the race the athletes cycled between three and seven hours and covered 128 to 219 km on each of the seven days of the competition. They used continuous glucose monitor technology to monitor glucose and smart insulin pens to automatically record insulin dosing and timing.

The results provide a unique insight into current practices of elite athletes living with type 1 diabetes and new evidence of the habitual eating and insulin dosing patterns of professional athletes during multi-stage endurance events.

Why is this study important?

This manuscript provides a unique and exciting insight into current practices of elite athletes living with type 1 diabetes. Before conducting this observational study, we were not aware of the habitual eating or insulin dosing patterns of professional athletes during multi-stage endurance events such as the Tour of California. For people living with diabetes this is important because it demonstrates that although there are huge challenges, anything is possible. It’s also important for us to note that although the riders performed well and generally had excellent in-ride glycaemia, there was a tendency to struggle with night time hypoglycaemia. The risk of nocturnal hypoglycaemia is something we are aiming to help with in the future.

What are the main findings?

The riders, from Team Novo Nordisk (TNN), spent a high proportion of their time in target glycemic range (3.9-10.0 mmol/L) during cycling, with little time in hypoglycemia (<3.9 mmol/L) over the seven days. The average in-ride carbohydrate intake was 76 grams per hour which is in line with contemporary nutrition guidelines for athletes without diabetes. In-ride nutrition consisted primarily of energy gels, high-carbohydrate energy bars, rice cakes, and bananas. Fluids consisted of water, a low- carbohydrate sports drink containing electrolytes, or cola.

How can this change the way look at exercise and diabetes in the future?

Our data will form the foundations from which our Research Team can now explore strategies for people living with type 1 diabetes to better manage their glucose during exercise. Second, the comprehensive range of technologies used in this study such as continuous glucose monitoring, smart insulin pens and cycle power-meters, during a dynamic and challenging event such as the Tour of California, demonstrate what is possible for Research Team.