Circadian Rhythm and Metabolic Effects of Exercise

Physical exercise is efficacious in controlling blood glucose levels in individuals with Type 2 diabetes. An individual's exercise capacity and ability to utilize glucose as an energy source oscillates throughout the day. Hence, the beneficial effects of exercise on blood glucose levels may depend on the time of day when the exercise bout is performed. However, the time of day in which the most beneficial adaptations to exercise can be achieved remains unknown. This project aims to answer the following questions: Does time of day impact the beneficial effects of exercise on blood glucose? If so, when can the most beneficial effects of exercise be achieved? Which metabolic mechanisms links time of day, exercise and blood glucose control? To address these questions, individuals with or without Type 2 diabetes will perform an exercise session at two different times (09:00 and 16:00), and continuous glucose monitoring will be used to assess the effects of exercise on blood glucose. We will determine the specific metabolic processes which promote the most beneficial blood glucose response. To achieve this, we will measure which metabolic substrates (carbohydrates, lipids and proteins) are used and which metabolites produced in blood, skeletal muscle and adipose tissue in response to exercise at different times of the day.