Yardley JE, Zaharieva DP, Jarvis C, Riddell MC. The "Ups" and "Downs" of a Bike Race in People with Type 1 Diabetes: Dramatic Differences in Strategies and Blood Glucose Responses in the Paris-to-Ancaster Spring Classic. Can J Diabetes. 2015 Apr;39(2):105-10.
For individuals with type 1 diabetes, physical activity has numerous health benefits including improved insulin sensitivity, reduced risk of developing cardiovascular disease, and improved overall quality of life. However, managing blood sugar levels during exercise can be quite frustrating and complicated at times. One of the biggest barriers to physical activity is the risk of low blood sugar (hypoglycemia). Currently, limited diabetes management guidelines exist for athletes with type 1 diabetes competing at higher intensity and longer duration events. This observational study was conducted on six males with type 1 diabetes before, during, and following the Paris-to-Ancaster cycling race- a 2-3 hour on and off road “cycle-cross” race. All participants completed the cyclocross bike race; however, many different strategies for managing blood sugar levels were employed. To reduce the risk of low blood sugars during the race, almost all participants reduced their pre-race insulin levels and/or consumed carbohydrates before the race (ranging from ~20-60 grams of carbohydrate per hour of exercise performed). With the exception of one participant that had severely elevated blood sugar concentrations before the race (hyperglycemia), all participants experienced a decline in blood sugar levels despite taking actions to try and reduce the likelihood of this occurring. In summary, individuals with type 1 diabetes are capable of completing high-intensity and longer durations events, but insulin adjustments and carbohydrate supplementation are important factors to consider before engaging in these types of events. Frequent monitoring of blood glucose levels before, during, and after an event is essential for understanding one’s own response to physical activity.
Article summary written by: Dr. Michael C. Riddell.
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