Impact of Body Composition on Peak Oxygen Uptake After Cardiac Rehabilitation

Peak oxygen uptake (VO₂ peak), standardized to total body mass (ml/kg/min) is a predictor of morbidity and mortality in cardiovascular disease patients. However, subsets of individuals undergoing exercise based cardiac rehabilitation (CR) show no improvement or reduction in VO₂ peak despite improvement in other functional measures. Our aim is to assess the influence of CR on lean mass, and the effect of body composition compared to total body mass changes on peak VO₂ following CR.

This pre-post intervention study included adults >18 years old who completed CR between 2015-2022 at Mayo Clinic, Rochester. All patients completed both dual energy X-ray absorptiometry (DXA) and cardiopulmonary exercise testing (CPET) for measurement of body composition (total mass and lean mass) and VO₂ peak pre-post CR. Improvement in VO₂ peak was defined as positive percent change. Descriptive statistics, paired t-tests, univariable and multivariable linear regression modeling were performed.

Of 140 subjects, 19.3% were female and 96.4% White with a mean (SD) age of 63 (12.5) years, BMI of 30.2 (5.82), and a mean of 27.1 (11.7) completed number CR sessions. Pre-post CR total body mass loss was -1.28 (3.18) kg and lean mass gain was 0.84 (2.86) kg. All changes were statistically significant (p<0.05). Pre-post CR VO₂ peak in absolute units had a percent change increase of 6.52 (13.1) mL/min, relative (corrected for total body mass) increase of 8.24 (13.6) mL/kg/min, and relative to lean mass increase of 5.73 (13.4) mL/lean-kg/min. Pre-post percentage of subjects with a positive change in peak VO₂ in absolute units was 70%, relative was 75%, and relative to lean mass was 67.9%. Multivariable regression showed statistical significance in peak VO₂ percent change for all units when adjusted for pre-CR peak VO₂.

Our findings demonstrate significant increases in lean mass and VO₂ peak following CR, with larger improvements reflected in units adjusted for total mass compared to other methods. These data suggest the reporting methodology for change in VO₂ peak following CR impact overall results.