Which Components of the Haemodynamic Response to Active Stand Predict Cardiovascular Disease and Mortality? Data From The Irish Longitudinal Study on Ageing

Background: An integrated haemodynamic response during standing may serve as an integrative marker of neuro-cardiovascular function. Individual components of both heart rate (HR) and blood pressure (BP) responses to active stand (AS) have been linked with cardiovascular disease (CVD) and mortality. We assessed longitudinal associations between entire HR/BP response curves during AS, incident CVD and mortality over 12 years. Methods: Beat-to-beat measurements of dynamic HR/BP responses to AS were conducted in 4,336 individuals (61.5±8.2 years; 53.7% female). Functional Principal Components Analysis was applied to HR/BP response curves and their association with CVD and mortality assessed. We hypothesised that integrating BP/HR information from the entire haemodynamic response curve may uncover novel associations with both CVD and mortality. Results: Higher systolic BP (SBP) before AS and blunted recovery of SBP during AS was associated with all-cause mortality over 12-years (Hazard Ratio [HR]: 1.14; 1.04, 1.26; p=0.007). Higher baseline/peak HR and lower HR from 30 seconds post stand onwards were associated with lower mortality due to circulatory causes (HR: 0.78; 0.64, 0.95; p = 0.013). Higher HR throughout AS was associated with mortality from other causes (HR: 1.48; 1.22, 1.80; p<0.001). Findings persisted on robust covariate adjustment. Conclusions: We observed distinct relationships between HR/BP responses to AS and 12-year incident CVD and mortality. Integrating the entire haemodynamic response may reveal more nuanced relationships between HR/BP responses to AS, CVD and mortality - serving as an integrative marker of neuro-cardiovascular health in midlife and beyond.