Effort intolerance is common among patients with type 2 diabetes, wherein it predicts the development of heart failure. Difficult to assess subjectively, it can be confirmed and quantified with cardiopulmonary exercise testing (CPET), in which oxygen consumption (VO2) and a multi-organ study of exercise physiology can identify the determinants of effort intolerance and estimate the risk of progression to overt heart failure. Diabetes is independently associated with an early reduction in VO2, which is further worsened by obesity and diabetes-related complications, with a complex and still unclear pathophysiology. Despite its diagnostic and prognostic value, current guidelines do not recognize effort intolerance as a condition to be identified and treated in patients with diabetes, thus leaving a diagnostic and preventive gap. Identifying patients with reduced VO2 and a higher cardiovascular risk is crucial in current diabetology, where the latest medications have been shown to slow the progression toward heart failure.
In this article, we will explore the CPET methodology and the main indices of exercise capacity, focusing on the practical utility of this method in patients with type 2 diabetes for cardiovascular prevention, particularly heart failure. Additionally, we will provide updates on current and future research applications to prevent heart failure in patients with diabetes.