What is it about?
This study investigates the mechanisms behind exercise capacity in adults with type 2 diabetes mellitus (T2DM), focusing on both the central (heart) and peripheral (muscle) components. We found that cardiac output is the main determinant of exercise capacity. Differences in peripheral oxygen extraction seem to result mainly from blood flow (perfusion) rather than from intrinsic mitochondrial limitations. Finally, our results suggest that peak cardiac output and peak muscle perfusion are not directly equivalent and do not occur at the same time.
Featured Image
Photo by Fat Lads on Unsplash
Why is it important?
Adults with type 2 diabetes (T2DM) often present with a significantly reduced exercise capacity. This reduced exercise capacity is a key factor contributing to adverse clinical outcomes and reduced life expectancy in this population. An improvement in exercise capacity by one metabolic equivalent of a task (MET) is associated with a 14–19% reduction in mortality risk. However, exercise capacity varies widely among adults with T2DM. Therefore, a better understanding of the underlying mechanisms associated with a lower exercise capacity in adults with T2DM is needed to facilitate early preventive interventions.
Perspectives
Our findings indicate that in adults with type 2 diabetes, reduced exercise capacity is primarily driven by limitations in cardiac output rather than intrinsic defects in muscle oxygen utilization. Importantly, participants with the lowest fitness were more frequently treated with bèta-blockers and diuretics, reflecting longer diabetes duration and a higher burden of comorbidities. While clinically indicated, these medications further decrease cardiac output and local muscle perfusion, thereby exacerbating exercise intolerance. This contributes to a vicious cycle: reduced cardiac performance leads to lower activity levels, which in turn accelerates metabolic decline and comorbidity progression. These observations underscore the importance of prescribing exercise early in the disease course, aiming to postpone the initiation of blood pressure lowering medication. In patients already treated with bèta-blockers, structured physical activity remains essential to counterbalance the medication-induced decline in fitness.
Matthijs Michielsen
Associatie KU Leuven
Read the Original
This page is a summary of: Exploring the limits of exercise capacity in adults with type II diabetes, PLOS One, September 2025, PLOS,
DOI: 10.1371/journal.pone.0331737.
You can read the full text:
Contributors
The following have contributed to this page
