Assessing the efficacy and acceptability of timed exercise to improve glucose variability and metabolic flexibility in adults with prediabetes

Being more active is an important part of treatment for adults with prediabetes. Exercise is one of the simplest and most effective ways to bring down blood glucose levels. However, lack of time is a common barrier to performing exercise regularly. The high-intensity interval training (HIIT) and timed exercise are two new exercise approaches which require lesser time commitment, but their health benefits are equally similar to the traditional exercise modality. But whether combining both principles (HIIT and timed exercise) could restore metabolic health in adults with prediabetes remains unknown. Using a mixed-methods approach, the REALIGN project aims to investigate whether performing HIIT at a certain time of day is more beneficial than performing it at another time of day to improve glucose excursion profile and fuel switching. Whereas the secondary aim is to explore the views and experiences of adults with prediabetes on timed HIIT program. To achieve these aims, adults with prediabetes will be randomly assigned to a 12-week HIIT program either in the morning or afternoon. A continuous glucose sensor will be used to assess the changes in their blood glucose fluctuation profile. Whereas two types of calorimeters (respiration chamber and ventilated hood system) will be used to assess the body’s ability to switch between carbohydrates and fats as energy sources in response to feeding and fasting conditions. At the end of the program, some of the participants will be interviewed to explore their perceptions of the timed HIIT exercise. This interdisciplinary project will take place at the German Diabetes Center (DDZ) which houses cutting-edge infrastructures in exercise and metabolism research. This project is linked to key training aiming to advance the fellow’s competency in experimental and transferable skills to enhance professional maturity and develop independence.