Sympathetic neural reactivity to mental stress differs in black and non-Hispanic white adults
Black adults have a higher risk of hypertension compared to non-Hispanic white (NHW) adults, but physiological mechanisms underlying this predisposition remain unclear. This study compared muscle sympathetic nerve activity (MSNA) responses to mental stress in a group of young black and NHW participants. We hypothesized that the sympathoexcitation associated with mental stress would be greater in black adults compared to NHW. Thirty-five male adults (19 black, 23±1 years; 16 NHW, 22±1 years) were examined during a 5 min supine baseline and 5 min of mental stress (via mental arithmetic). Baseline mean arterial pressure (80±2 vs. 82±1 mmHg), heart rate (61±4 vs. 61±2 beats/min), MSNA (13±1 vs. 15±2 bursts/min), and sympathetic baroreflex sensitivity (-1.1 ± 0.4 vs -1.5 ± 0.3 bursts/100hb/mmHg) were not significantly different between NHW and black adults (p>0.05), respectively. MSNA reactivity to mental stress was significantly higher in NHW compared to black adults (time × race, p=0.006), with a particularly divergent responsiveness during the first minute of mental stress in NHW (Δ4±1 burst/min) and black (Δ-2±2 burst/min; p = 0.022). Blood pressure and heart rate reactivity to mental stress was similar between groups. In summary, black participants demonstrated a lower MSNA responsiveness to mental stress compared to NHW adults. These findings suggest that despite a higher prevalence of hypertension, blacks do not appear to have higher neural and cardiovascular responsiveness to mental stress when compared to NHW.
Journal of Applied Physiology
Fonkoue, I. T.,
Schwartz, C. E.,
Carter, J. R.
Sympathetic neural reactivity to mental stress differs in black and non-Hispanic white adults.
Journal of Applied Physiology,
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