To prevent hypoglycemia during prolonged exercise (>30 minutes), additional carbohydrate intake is frequently required. Carbohydrate intake required will vary with insulin regimens, timing and type of exercise as well as starting blood glucose level. In addition to the amount of carbohydrate ingested, the timing of carbohydrate intake could also have an impact on glucose control during exercise. Therefore, the objective of this study will be to compare the efficacy of two snacking strategies to maintain glucose levels in the target range during an exercise period in adults with type 1 diabetes: 1) a snack containing ~0.5g of carbohydrates per kilogram of body weight - rounded to the nearest 5g - given 5 minutes before exercise; 2) a snack containing ~0.5g of carbohydrates per kilogram of body weight - rounded to the nearest 5g - distributed this way: ~40% given 5 minutes before exercise, ~30% after 20 minutes of exercise and the last ~30% after 40 minutes of exercise.