Test his blood glucose and snack before and during exercise:

Regular exercise is essential for people with T1D. But exercise and sports activities make insulin more effective, so Jeremy will typically take a snack containing 15-40 g of carbohydrate (such as dried fruit) before and at intervals during exercise or he may reduce his mealtime insulin dose in anticipation of exercise within the following hour. The effects of vigorous exercise can persist for several hours or more and can contribute to the risk of hypoglycemia.