Early impairment of two arms of the baroreflex response in young normotensive patients with obesity

<i>Objective</i>. Hypertension increasingly affects younger populations alongside rising obesity rates, and impaired baroreflex (BR) function could contribute to its development. This study investigated changes in BR control of the cardiac chronotropic (ccBR) and vascular resistance (vrBR) arms in young normotensive patients with obesity and explored associations with sex- and age-independent anthropometric measures (body mass index (iso-BMI) and waist to hip ratio (OSS of WHR)), insulin resistance (HOMA_IR), and arterial stiffness index CAVI₀.<i>Approach.</i>Twenty-three normotensive adolescents and young adults with obesity (17 females, median age: 17.1 years) and twenty-two sex- and age-matched healthy lean participants (16 females, median age: 17.4 years) were examined during four phases: supine rest, head-up-tilt (HUT), supine recovery, and mental arithmetics task (MA). The causal coupling and gain in the frequency-domain of the ccBR and vrBR arms were assessed non-invasively from the spontaneous variability series of arterial pressure, heart period, and peripheral vascular resistance using a partial spectral decomposition method in the low frequency band (0.04-0.15 Hz).<i>Main results.</i>Patients with obesity showed lower ccBR gain during HUT and persistently lower vrBR gain during supine rest and HUT. No significant associations were found between iso-BMI, OSS of WHR, HOMA_IR, CAVI₀, and spectral parameters during supine rest, except for a significant negative correlation between iso-BMI and changes in ccBR spectral gain as a response to MA.<i>Significance.</i>Advanced non-invasive methods accounting for causality in evaluating two BR arms revealed early BR impairment in young participants with obesity, affecting both the ccBR arm and the less-explored vrBR arm.