Blunted Spontaneous Sympathetic Baroreflex Sensitivity in Young Healthy Black Men

Authors

Damsara Nandadeva, University of Texas at ArlingtonFollow
Benjamin E. Young, University of Texas at ArlingtonFollow
Jody L. Greaney, University of Texas at ArlingtonFollow
Paul J. Fadel, University of Texas at ArlingtonFollow

Abstract

The prevalence and severity of hypertension in black individuals are greater than in any other racial/ethnic group in the United States. The arterial baroreflex dynamically regulates blood pressure (BP) on a beat-to-beat basis via alterations in cardiac output and peripheral vascular resistance, and impairments in arterial baroreflex function are well-documented in patients with hypertension. Previous reports suggest that black individuals have a reduced cardiac baroreflex sensitivity compared to their white counterparts. However, the peripheral sympathetic component of the arterial baroreflex has never been examined in young healthy black individuals. PURPOSE: We sought to compare spontaneous sympathetic baroreflex sensitivity between young healthy black and white men. METHODS: Seven healthy black (age: 20 ± 1 years, BMI: 24.3 ± 1.3 kg/m²) and seven healthy white (age: 22 ± 1 years, BMI: 27.0 ± 1.2 kg/m²) men participated in the study. Heart rate (ECG), beat-to-beat BP (finger photoplethysmography) and muscle sympathetic nerve activity (MSNA; peroneal microneurography) were continuously measured during a 20-minute resting period. MSNA was quantified as burst incidence (bursts/100 heartbeats) and averaged over 3-mmHg diastolic BP bins for each individual. The linear relationship between the spontaneous changes in MSNA and diastolic BP was assessed using a weighted linear regression analysis. Sympathetic baroreflex sensitivity was quantified as the slope of MSNA burst incidence to diastolic BP. RESULTS: Heart rate, systolic BP, diastolic BP and mean arterial pressure was not different between the 2 groups (p > 0.05 for all). MSNA burst incidence was also similar between the two groups (black men, 16 ± 2.2 burst/100 heartbeats vs. white men, 21.4 ± 2.0 bursts/100 heartbeats, p = 0.10). The slope of MSNA burst incidence to diastolic BP was significantly lower in black compared to white men (black men, -2.20 ± 0.4 bursts/100 heartbeats/mmHg vs. white men, -3.36 ± 0.3 bursts/100 heartbeats/mmHg, p = 0.03). CONCLUSION: These preliminary data suggest that young healthy black men have a blunted sympathetic baroreflex sensitivity compared to white men.

Recommended Citation

Nandadeva, Damsara; Young, Benjamin E.; Greaney, Jody L.; and Fadel, Paul J. (2020) "Blunted Spontaneous Sympathetic Baroreflex Sensitivity in Young Healthy Black Men," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 12, Article 109.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss12/109