Olson, Thomas P.

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.

Heart failure with preserved ejection fraction (HFpEF) is associated with exercise intolerance, with respiratory muscle dysfunction as a contributing factor. Patients with HFpEF have exaggerated cardiovascular responses to respiratory muscle metaboreflex activation. In this study, we determined the impact of inspiratory muscle training (IMT) on the respiratory muscle metaboreflex in HFpEF. We found that 8 wk of IMT improved inspiratory muscle strength and attenuated the respiratory muscle metaboreflex-mediated cardiovascular responses in patients with HFpEF.