Blood pressure reactivity at onset of mental stress determines sympathetic vascular response in young adults

Abstract

We have previously shown in young males that the rate of rise in blood pressure (BP) at the onset of mental stress determines whether or not muscle sympathetic nerve activity (MSNA) has a role in driving the pressor response. The aim of this study was to investigate these interactions in young females. BP and MSNA were recorded continuously in 19 females and 21 males during 2‐min mental stressors (mental arithmetic and Stroop test). Physical stressor tasks (cold pressor, handgrip exercise, postexercise ischemia) were also performed. During the first minute of mental arithmetic, the rate of rise in mean arterial pressure (MAP) was significantly greater in negative responders (mean decrease in MSNA) compared with positive responders (mean increase in MSNA) in both males (1.9 ± 0.7 vs. 0.7 ± 0.3 mmHg/sec) and females (1.0 ± 0.3 vs. 0.5 ± 0.2 mmHg/sec). For the Stroop test, there was no significant difference in the rate of the rise in BP between positive and negative responders (P > 0.05). However, peak changes in MAP were significantly greater in negative responders compared with positive responders in both males (22 ± 6 vs. 13 ± 3 mmHg) and females (12 ± 2 vs. 6 ± 1 mmHg). Sympathetic baroreflex sensitivity was greater in negative responders and may contribute to the fall in MSNA experienced by these individuals during mental stress. During physical stressors there were consistent increases in BP and MSNA in males and females. The findings suggest that, in both males and females, BP reactivity at the onset of mental stress dictates whether or not there is an increase or decrease in MSNA.

Sympathetic neural reactivity to the Trier social stress test

“…social stress), reduces the need for peripheral sympathetic activation to meet blood pressure requirements. Conversely, if the physiological system is not properly primed during the preparation phase, augmented peripheral sympathetic activity may be necessary to achieve the appropriate blood pressure response to the speech and maths portions, similar to the findings of El Sayed et al (2016Sayed et al ( , 2018. Whether reductions in MSNA in response to mental stress are beneficial remains to be determined, as this may simply indicate excessive reactivity at a different organ bed, such as the heart (Esler, 2022), which may be equally detrimental as excessive peripheral sympathetic activation.…”

“…Despite wide inter ‐individual variability, intra ‐individual responses to mental stress and arousal appear to be reproducible (Donadio et al., 2002; Fonkoue & Carter, 2015). While the influence of factors such as baroreflex function (Anderson et al., 1991; Durocher et al., 2009, 2011), rate of blood pressure changes (El Sayed et al., 2016, 2018), psychological factors (Bigalke & Carter, 2021) and perceived stress (Callister et al., 1992; Carter et al., 2008) have been explored, a consensus has not yet been reached regarding the physiological underpinning of variations in stress reactivity. Many commonly utilized stress tests are performed with the addition of multiple confounds such as irregular breathing patterns and depth, active talking, muscle movements and other confounds that may impact MSNA recordings and subsequent data interpretation.…”

Analysis of Systolic Blood Pressure Level and Short-Term Variability in Masked Hypertension

“…A major determinant of blood pressure variability depends on baroreceptor sensitivity [ 21 ]. When the vascular structure changes significantly, it may reduce the sensitivity of arterial baroreceptors by limiting the extension of baroreceptors, and the lower sensitivity would be expected to lead to increased blood pressure variability [ 22 , 23 ]. Moreover, atherosclerosis itself may enhance blood pressure fluctuations associated with small changes in cardiac output.…”

Countdown before voluntary exercise induces muscle vasodilation with baroreflex-mediated decrease in muscle sympathetic nerve activity in humans

“…Similar to our findings, Callister et al (4) reported that total MSNA from the radial nerve of the arm decreased when arterial pressure increased before starting voluntary leg-cycling exercise, although they did not examine whether cerebral activation and/or muscle vasodilation occurred before starting voluntary exercise. In addition, El Sayed et al (7) reported that during mental stress ⌬MAP peak was greater in subjects who experienced decreases in MSNA burst frequency of the peroneal nerve and suggested that the reduction in MSNA was likely caused by the baroreflex mechanism. These results suggest that the baroreflex accounts for the reduced MSNA in response to the increase in MAP during mental stress or preparation for starting voluntary exercise.…”