A number of recent studies have highlighted large interindividual variability of muscle sympathetic nerve activity (MSNA) responsiveness to mental stress in humans. The purpose of this study was to examine blood pressure (BP) and MSNA responsiveness to mental stress in a large and generalizable cohort of young adults with and without family history of hypertension (FHH). We hypothesized that subjects with FHH would demonstrate greater sympathoexcitation to mental stress than subjects without FHH. A total of 87 subjects (55 men, 32 women; 18-40 years) from recently published (n=45) and ongoing (n=42) studies were examined. 57 subjects had complete MSNA recordings at baseline (19 with FHH, 38 without FHH). Heart rate (HR), BP, and MSNA were recorded during five min of supine rest and five min of mental stress (via mental arithmetic). Resting MSNA and HR were not statistically different between subjects with and without FHH (p>0.05), whereas resting MAP was higher in FHH participants (86±2 vs. 80±1 mmHg; p<0.05). Mental stress increased MSNA in FHH subjects (∆5±1 bursts/min), but not in subjects without FHH (∆1±1 bursts/min; time × group, p<0.01). Mental stress increased MAP (∆12±1 mmHg and ∆10±1 mmHg; p<0.001) and HR (∆19±2 beats/min and ∆16±2 beats/min; p<0.001) in subjects with and without FHH, but these increases were not different between groups (time × group, p≥0.05). MSNA and BP reactivity to mental stress was not correlated in either group. In conclusion, FHH was associated with heightened MSNA reactivity to mental stress despite a dissociation between MSNA and BP responsiveness.
- family history hypertension
- blood pressure
- muscle sympathetic nerve activity
- cardiovascular reactivity hypothesis
- Copyright © 2016, American Journal of Physiology - Heart and Circulatory Physiology