Magnitude and variability of blood pressure and renal vascular conductance responses to postural changes, exercise,...

We developed a noninvasive approach to measure vascular responses to sympathetic stimuli. We hypothesized that standing, handgrip exercise, or cold exposure would raise blood pressure (BP) and lower renal vascular conductance (RVC). BP was recorded continuously and renal arterial velocity was measured using renal Doppler ultrasound. Repeated measures one-way ANOVA with Dunnett's post hoc test was used to compare BP during stimulation against baseline. Intraclass correlation analysis was used to compare first and second visits. Seven women and four men aged 29.9 ± 4.7 years participated. On first visits, standing from supine raised systolic BP by 11.9 ± 2.6 mmHg (p = 0.0018) and diastolic BP by 15.0 ± 1.9 mmHg (p < 0.0001). Handgrip exercise raised systolic BP by 15.9 ± 4.1 mmHg (p = 0.0146) and decreased systolic RVC by 0.68 ± 0.26 cm/s/mmHg (p = 0.0049). Cold increased systolic BP by 27.8 ± 3.4 mmHg (p < 0.0001) and decreased systolic RVC by 0.32 ± 0.07 cm/s/mmHg (p = 0.0049). BP and RVC responses were similar from visit one to visit two; however, most outcome measurements were not correlated within individuals. These findings expand our understanding of vasoregulation in Black adults and guide studies to characterize vascular function in the future.