Grant: DRA : Canada Graduate Research Scholarship - Doctoral Program (CGRS D)

People with type 1 diabetes (T1D) face many challenges when it comes to exercising regularly, even though exercise is well known to improve health, fitness, and blood sugar control. One of the biggest barriers is the fear of low blood sugar (hypoglycemia) during or after exercise. Low blood sugar can cause shaking, sweating, confusion, and in severe cases, loss of consciousness. Because of this risk, many people with T1D are hesitant to exercise, or they must eat extra carbohydrates before and during activity, which can feel discouraging and counterproductive. Recent studies suggest that the timing of exercise relative to meals may change how blood sugar responds. For example, exercising before breakfast, in a fasted state, often causes blood sugar to rise, while exercising after breakfast tends to make blood sugar fall. Exercising in a fasted state may therefore lower the risk of hypoglycemia. It may also increase fat use by the muscles and improve insulin sensitivity, which could lead to needing less insulin overall. This project includes three related studies. The first compared blood sugar responses to resistance exercise performed before versus after breakfast. It showed that fasted exercise caused fewer episodes of low blood sugar and gave more predictable results. Building on this, the second study is a clinical trial testing three months of fasted versus fed exercise training in adults with T1D and abdominal obesity. We are examining how exercise timing affects daily insulin needs, fat in the liver and muscles, and blood sugar patterns. The third study will survey people with T1D across Canada to better understand their exercise habits, preferences, and barriers. Together, these studies will help determine whether fasted exercise is a safe and effective way to make exercise easier and more beneficial for people with T1D. The ultimate goal is to provide strategies that reduce fear of hypoglycemia, improve health, and empower more people with T1D to be active.