Sharif, Salaheddin M.

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.

Introduction: Cardiac rehabilitation (CR) is known to improve peak oxygen uptake (VO 2 peak) and body composition (BC). However, not all CR patients improve VO 2 peak and it remains unclear if non-responders also exhibit limited improvement in BC. This study aimed to examine if non-responders to VO 2 peak also demonstrate limited improvement in BC and whether BC is related to VO 2 peak changes in CR patients. Methods: Retrospective analysis of patients who completed CR between 2015 and 2022 at Mayo Clinic. The study included 143 patients who completed both dual-energy X-ray absorptiometry and cardiopulmonary exercise testing before and after CR. Patients were grouped by VO 2 peak response to CR (36 non-responders=Δ≤0 vs 107 responders=Δ>0 mL/kg/min). Within and between-group differences were assessed by paired and independent t-tests respectively. Regression models were used to evaluate whether baseline BC or ΔBC predict VO 2 peak changes. Results: As an entire cohort there were significant mean improvements in VO 2 peak and BC (Table 1, p<0.05). VO 2 peak increased in 75% of patients (responders: Δ 2.9±2 vs non-responders: Δ -2.1 ±2, mL/kg/min, p<0.05). There were no significant differences in baseline characteristics between groups including BC (Table 2, p>0.05); however, non-responders had significantly shorter duration and exercise sessions compared to responders (Table 2, p<0.001). Non-responders for VO 2 peak exhibited a significant improvement in body fat mass, body lean percentage, body fat percentage, and fat mass index (all p<0.001), with no differences in ΔBC between groups (Table 3). Regression models revealed no significant BC predictors for VO 2 peak. Conclusion: Despite significant improvements in BC, 25% of patients did not improve VO 2 peak with CR. These data suggest VO 2 peak improvement is not related to baseline BC or change in BC. These findings suggest the need for additional strategies to maximize improvements in VO 2 peak for patients undergoing CR.