Relationship between change in body composition and cardiorespiratory fitness during cardiac rehabilitation in patients with cardiovascular disease

Background Cardiac rehabilitation (CR) improves peak oxygen uptake (VO 2 peak) and body composition in patients with cardiovascular disease. However, improvement in VO 2 peak is not observed in all patients following a CR program, and whether VO 2 peak non-responders also demonstrate limited changes in body composition remains unclear. This study aimed to examine the association between changes in VO 2 peak and body composition in patients undergoing a CR program. Methods Retrospective analysis of patients who completed CR between 2015 and 2022 at Mayo Clinic. The study included 143 patients who completed cardiopulmonary exercise testing and dual-energy X-ray absorptiometry pre- and post-CR. Patients were grouped by the change in relative VO 2 peak response to CR (responders= Δ>0 vs non-responders=Δ ≤0 mL/kg/min). Two-way repeated ANOVA was used to compare groups, and regression models were used to examine the associations between baseline body composition and changes in body composition with VO 2 peak change. Results Among the cohort, 26% were classified as non-responders based on relative VO 2 peak measurements. Both groups exhibited a significant improvement in most body composition variables including body fat mass, body fat percentage, body lean percentage, and fat mass index (all p<0.001), with no differences in the percentage of change in body composition variables between groups (p>0.05). Regression models demonstrated that neither baseline body composition nor changes in body composition were significantly associated with changes in VO 2 peak. Conclusion Our data suggest that baseline and change in body composition were not significantly associated with changes in VO 2 peak in patients undergoing the CR program.