Exercise-Derived Hemodynamics and 6-Minute Walk Distance in Hypertension

Abstract Background:Patients with hypertension commonly exhibit reduced exercise capacity. Impedance cardiography (ICG) enables continuous, non-invasive assessment of exercise-derived hemodynamic parameters; however, the relative associations of different ICG-derived parameters with exercise capacity remain unclear. Methods:In this retrospective cross-sectional study, 211 patients with hypertension who completed both ICG assessment and the six-minute walk test (6MWT) were enrolled. Exercise-derived hemodynamic parameters, including maximum heart rate (HRmax), stroke volume (SV), cardiac output (CO), and systemic vascular resistance (SVR), were continuously measured using the PhysioFlow(R) system. Univariable and multivariable linear regression analyses were performed to evaluate the associations between ICG-derived parameters and six-minute walk distance (6MWD). HRmax tertile and subgroup analyses were subsequently conducted. Results:In the final multivariable model, age ({beta} = -2.76, 95% CI, -3.85 to -1.67, P < 0.001), male sex ({beta} = 33.50, 95% CI, 8.40-58.60; P = 0.009), and HRmax ({beta} = 1.26, 95% CI, 0.69-1.83; P < 0.001) were independently associated with 6MWD. 6MWD increased progressively across HRmax tertiles (P for trend < 0.001). The positive association between HRmax and 6MWD remained consistent across all prespecified and exploratory subgroups. Conclusions:Among multiple exercise-derived ICG hemodynamic parameters, HRmax demonstrated the strongest and most consistent independent association with exercise capacity in patients with hypertension. These findings suggest that HRmax may represent the most informative dynamic hemodynamic parameter during exercise and that combining ICG with the 6MWT may provide a simple and accessible complementary approach for evaluating exercise capacity.