ESC Congress 2026 Abstract · Oct 26, 2026
Association between phase angle and aerobic capacity and improvement in acute-phase cardiac rehabilitation: implications for functional assessment
By Sornek I, Petrasch G, Klimek M et al.
Background: Aerobic capacity (AC) is a prognostic factor for mortality and re-hospitalization in cardiovascular disease patients. In the early post-intervention phase exercise stress testing is not feasible. Training strategies for AC are based on patients’ subjective rate of perceived exertion (RPE). They often misestimate intensities required for supercompensation, hence lack training effects. Phase angle (PhA) from bioelectrical impedance analysis (BIA) serves as indirect marker of cellular health, membrane integrity, and hydration status. Given the essential role of skeletal muscle and cellular function in oxygen uptake and utilization, it is physiologically plausible that PhA is associated with AC outcomes. Purpose: Our aim was to investigate PhA as predictor for post-rehabilitation AC outcomes. Methods: This retrospective monocentric cohort study analyzed data from patients referred to in-patient exercise-based cardiac rehabilitation (EBCR) from December 2022 to June 2024. Whole-body PhA was assessed using BIA, and AC quantified by the 6-minute walking distance (6MWD), both pre and post EBCR. PhA was derived from the relationship between resistance (R) and reactance (Xc) at 50 kHz (PhA (degrees) = arctan(Xc/R) × (180/π)). Multivariable linear regressions were performed to examine the association between PhA and AC (6MWD at discharge and change in 6MWD). Models were adjusted for age, sex, body mass index, and 6MWD at admission. Results: A total of 865 patients were included in this analysis (22.2% female) with a median rehabilitation stay of 20 days (Q1-Q3: 20-27) (Table 1). In multivariable analysis, admission PhA was independently associated with higher 6MWD at discharge (β = 21.26 m per 1° increase, 95%CI 9.72–32.80; p<0.001). Older age (β = −1.73 m per year, 95%CI −2.52 to −0.94; p<0.001) and higher BMI (β = −5.95 m per kg/m², 95% CI −7.64 to −4.26; p<0.001) were associated with lower 6MWD, while higher admission 6MWD was positively associated with discharge 6MWD (β = 0.44 m per m, 95%CI 0.38–0.50; p<0.001). Admission PhA was also independently associated with greater improvement in 6MWD (β = 7.42 m per 1° increase, 95%CI 3.68–11.16; p<0.001). Older age (β = −0.66 m per year, 95%CI −0.92 to −0.41; p<0.001), higher BMI (β = −2.02 m per kg/m², 95%CI −2.57 to −1.47; p<0.001), and higher admission 6MWD (β = −0.19 m per m, 95%CI −0.20 to −0.17; p<0.001) were associated with smaller improvements (Figure 1). Conclusion: Higher PhA on admission is independently associated with both discharge AC and improvement during EBCR. Each 1° increase in PhA at EBCR initiation was associated with a 21.3 m higher 6MWD at discharge and a 7.4 m greater improvement. These results suggest that PhA, as feasible parameter of cellular health, represents an initial step toward a more objective approach to guide exercise prescription beyond subjective measures such as RPE. PhA may help identify patients with lower or higher adaptive potential.Figure 1