Abstract
Racial disparities have been observed in the vasoconstrictor response of peripheral arteries in skeletal muscle circulation following activation of the sympathetic nervous system (i.e., sympathetic vascular transduction). Specifically, non-Hispanic Black (BNH) individuals exhibit an enhanced vasoconstrictor response compared to non-Hispanic White (WNH) individuals. These differences may contribute to the higher incidence of hypertension and cardiovascular events observed in BNH populations. Additionally, BNH individuals face an increased risk and prevalence of various cerebrovascular and neurocognitive disorders. However, it remains unclear whether the heightened skeletal muscle vascular transduction response extends to the cerebral circulation. The Cold Pressor Test (CPT), a common method for inducing sympathetic nervous system activation, elicits significant cardiovascular and vascular reactions, including vasoconstriction. PURPOSE: This study aimed to investigate potential racial differences in cerebral vascular responses to sympathetic activation through the CPT in WNH and BNH individuals. METHODS: Thirteen non-Hispanic Black (BNH) participants (age: 21.07 ± 3.12 years, BMI: 23.72 ± 4.17 kg/m²) and nine non-Hispanic White (WNH) participants (age: 21.89 ± 3.26 years, BMI: 24.67 ± 3.97 kg/m²) took part in this study. Participants were positioned in a supine posture, and baseline (BSL) measurements were recorded over a six-minute period. Following baseline data collection, a sympathetic stimulus was applied by having participants submerge their hand in an ice water slurry for 2 minutes. Continuous measurements of middle cerebral artery blood velocity (MCAVmean) and non-invasive, beat-to-beat mean arterial pressure (MAP) were obtained throughout the protocol. Cerebral vascular tone was evaluated as cutaneous vascular conductance (CVCi; MCAVmean/MAP), with averages calculated for the final 30 seconds of both the BSL and Cold Pressor Test (CPT) phases. RESULTS: CVCi decreased significantly during the final 30 seconds of the Cold Pressor Test (CPT) in both the BNH and WNH groups (p < 0.001 and p = 0.007, respectively). However, no significant differences were observed between BNH and WNH participants at either baseline (p = 0.10) or during the last 30 seconds of CPT (p = 0.24). CONCLUSIONS: The hypothesis that both WNH and BNH individuals would experience a significant reduction in CVCi was confirmed. However, the expectation that BNH individuals would show a greater reduction in CVCi from baseline compared to WNH individuals was not supported by the data.
Recommended Citation
Brown, James E.; Moradi, Ario S.; Nagib, Hannah; Kolade, John; and Brothers, R. Matthew
(2025)
"Racial Impacts of Cerebral Vascular Responsiveness to Sympathetic Nervous System Activation,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
17, Article 161.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss17/161