Cardiovascular reactivity in mild hypertension

Physiological reactivity to acute mental stress in essential hypertension-a systematic review

Objective

Exaggerated physiological reactions to acute mental stress (AMS) are associated with hypertension (development) and have been proposed to play an important role in mediating the cardiovascular disease risk with hypertension. A variety of studies compared physiological reactivity to AMS between essential hypertensive (HT) and normotensive (NT) individuals. However, a systematic review of studies across stress-reactive physiological systems including intermediate biological risk factors for cardiovascular diseases is lacking.

Methods

We conducted a systematic literature search (PubMed) for original articles and short reports, published in English language in peer-reviewed journals in November and December 2022. We targeted studies comparing the reactivity between essential HT and NT to AMS in terms of cognitive tasks, public speaking tasks, or the combination of both, in at least one of the predefined stress-reactive physiological systems.

Results

We included a total of 58 publications. The majority of studies investigated physiological reactivity to mental stressors of mild or moderate intensity. Whereas HT seem to exhibit increased reactivity in response to mild or moderate AMS only under certain conditions (i.e., in response to mild mental stressors with specific characteristics, in an early hyperkinetic stage of HT, or with respect to certain stress systems), increased physiological reactivity in HT as compared to NT to AMS of strong intensity was observed across all investigated stress-reactive physiological systems.

Conclusion

Overall, this systematic review supports the proposed and expected generalized physiological hyperreactivity to AMS with essential hypertension, in particular to strong mental stress. Moreover, we discuss potential underlying mechanisms and highlight open questions for future research of importance for the comprehensive understanding of the observed hyperreactivity to AMS in essential hypertension.

Eveningness, depression and cardiovascular reactivity to acute psychological stress: A mediation model

The psychological pathways linking depression to blunted cardiovascular reactivity (CVR) are still being elucidated. The purpose of the present study was to test whether the association between eveningness, a diurnal/sleep-wake preference and CVR would be mediated by depressive symptoms. One hundred and eighty-two healthy young adults completed measures of morningness/eveningness (the Morningness-Eveningness Questionnaire; MEQ-SA), depressive symptoms (Hospital Anxiety and Depression Scale; HADS) and had their blood pressure and heart rate monitored throughout a standardised stress testing protocol. Results indicated that depressive symptoms were negatively associated with systolic blood pressure (SBP) but not diastolic blood pressure (DBP) or heart rate (HR) reactions to the stress task. Eveningness was also negatively associated with both SBP and DBP, but not HR. As such, those who reported increased depressive symptomology, and higher scores on eveningness displayed a more blunted cardiovascular response. Furthermore, the latter relationship was mediated by depressive symptoms such that those reporting higher scores on eveningness also reported increased depressive symptomology and this resulted in blunted CVR for SBP. These findings withstood adjustment for several confounding factors including time of testing. In conclusion, the present findings highlight the importance of considering eveningness when looking at the depression-blunted CVR relationship.

Vascular hyperreactivity in black Cameroonian hypertensive and normotensive patients: a comparative study

Introduction

Vascular hyperreactivity is a risk factor and a factor predicting hypertension (high blood pressure). Unlike other continents where several studies were carried out, it has rarely been studied in black Africa in general and in Cameroon in particular.

Methods

Vascular reactivity was measured by the cold test. Vascular hyperreactivity was defined as an increase in blood pressure > 20 mmHg for systolic and/or > 15 mmHg for diastolic. Khi², Man-Withney, Wilcoxon's signed ranks and logistic regression tests were used for statistical analysis.

Results

A total of 31 hypertensive and 31 normotensive patients matched by age and sex participated in this study. Vascular hyperreactivity was present in 77.4% hypertensive patients and 51.6% normotensive patients. There was a significant association between vascular hyperreactivity and hypertension [OR = 3.2 (1.07 - 9.63), p = 0.034]. The median arterial pressure was higher in responders compared to non-responders in the normotensive group. Age > 45 years, female sex, obesity and family history of hypertension appeared to be associated with vascular hyperreactivity, but only in normotensive patients.

Conclusion

Vascular hyperreactivity appears to be a risk factor for high blood pressure in black Cameroonians. It appeared to be associated with low blood pressure, age, sex, obesity and family history of hypertension but this was only in the normotensive.

Ambulatory arterial stiffness index is not correlated with the pressor response to laboratory stressors in normotensive humans

BACKGROUND

Ambulatory arterial stiffness index (AASI) is a novel estimate of arterial stiffness, which independently predicts cardiovascular mortality, even in normotensive individuals. Additionally, other markers derived from ambulatory blood pressure (BP) monitoring, including variability, pulse pressure, nocturnal dipping, and morning BP surge, have all been shown to be predictive of end-organ damage and cardiovascular disease. Exaggerated cardiovascular reactivity to sympathoexcitatory stimuli may also predict future incidence of hypertension. The purpose of this investigation was to test the hypothesis that AASI and other derivations of ambulatory BP, including pulse pressure, 24-h blood pressure variability, dipping, and morning surge, would be correlated with the pressor response to common physiological stress maneuvers.

METHOD

We measured continuous heart rate and arterial BP during head-up tilt, mental stress, cold pressor test, and isometric handgrip to fatigue in 67 healthy, normotensive, nonobese individuals (43 women, 24 men, mean age +/- SD: 28 +/- 6 years). Then, 24-h ambulatory BP was obtained, and AASI was defined as 1 minus the slope of diastolic on systolic BP in individual 24-h ambulatory BP recordings.

RESULTS

Although all measures were widely variable among patients, there was no relationship between AASI, pulse pressure, blood pressure variability, dipping, and morning surge with the pressor responses.

CONCLUSION

We conclude that in the absence of aging, cardiovascular, or autonomic disease, the novel stiffness index (AASI) or other ambulatory BP indices are either poorly correlated with or mechanistically unrelated to the complex pressor response to common provocations of sympathoexcitation.

Influence of apologies and trait hostility on recovery from anger

While there is growing evidence that quick recovery from stress is health-protective, relatively little is known about what factors affect recovery rates. We tested whether recovery from anger can be diffused with apologies. 184 participants performed a stress task involving verbal harassment and apologies. Participants were randomly assigned to one of four conditions: non-harassed control, good apology, pseudo-apology, or no apology. Measures of blood pressure and heart rate were taken at baseline, task and recovery periods. Participants scoring high in trait hostility displayed faster systolic blood pressure recovery when they received a genuine apology, but recovered more slowly when they received a pseudo-apology or no apology. Apologies did not influence subjective anger ratings. It was concluded that apologies may accelerate cardiovascular anger recovery among those with hostile personality predispositions.

Environmental tobacco smoke: association with cardiovascular function at rest and during stress

Chronic exposure to environmental tobacco smoke (ETS) contributes to cardiovascular disease morbidity and mortality, and ETS alters cardiovascular performance during exercise stress. However, no study has examined whether those with ETS exposure have altered cardiovascular functioning during psychological stress, relative to those with no substantial ETS exposure. Seventy-eight healthy, nonsmoking adult men with either high levels of current ETS exposure at home and work or no current or significant lifetime ETS exposure were tested in a stress reactivity protocol. Blood pressure and heart rate were monitored during rest and during two psychological stressors. Those with high ETS exposure had significantly elevated heart rate and blood pressure at baseline, relative to those with no exposure. The groups did not differ on their cardiovascular stress responses. These data suggest that chronic ETS exposure is associated with altered cardiovascular functioning at rest, but not during stress. Results are discussed with regard to the role of ETS on the development of heart disease among nonsmokers.

Vagal and cardiac reactivity to psychological stressors in trained and untrained men

PURPOSE

The aim of this study was to determine whether higher aerobic fitness is associated with enhanced vagal influences on the myocardium, resulting in moderation of chronotropic cardiac activity during psychological stress and recovery.

METHOD

Heart period (HP) and respiratory sinus arrhythmia (RSA) were obtained from 10 aerobically trained (AT) and 10 untrained (UT) college-aged men at rest and during three contiguous psychological challenges and 3 min of recovery. Ratings of perceived stress were obtained at the end of the rest period, at the midpoint of each stressor, and at 30 s into recovery. Time series methods were used to quantify RSA from the beat-to-beat HP series. Responsivity was assessed both in terms of absolute levels of activity and phasic changes in activity (task or recovery minus baseline).

RESULTS

Both groups reported similar levels of subjective stress throughout the experiment. The AT exhibited longer HP at rest and during psychological stress and recovery than did the UT. However, the groups did not differ on RSA at rest or during psychological stress and recovery, nor did they differ on phasic changes in RSA or HP during stress or recovery. Additionally, aerobic capacity was not correlated with absolute levels or phasic changes in RSA during psychological challenge for either group and, except in Min 2 for the UT, similar results were obtained for recovery.

CONCLUSIONS

The results supported the hypothesis that, among young men, higher aerobic fitness is associated with longer HP at rest and during psychological stress and recovery. However, the lower cardiac chronotropic activation observed among the AT relative to the UT was not paralleled by a group difference in the amplitude of RSA. These results suggest that the group difference in HP was not mediated directly by the vagal mechanisms manifested in the amplitude of RSA.

Usefulness of an exaggerated systolic blood pressure response to exercise in predicting myocardial perfusion defects in known or suspected coronary artery disease

The clinical importance of an exaggerated systolic blood pressure (BP) response to exercise, or exercise hypertension, is unclear. We have previously reported that exercise hypertension is associated with less severe angiographic coronary artery disease. This study sought to examine the association between exercise hypertension and ischemic "burden," as assessed by thallium-201 single-photon emission computed tomography. The cohort was comprised of consecutive adults (2,216 men, 1,229 women) referred for symptom-limited exercise thallium testing to evaluate known or suspected coronary artery disease. The main variable measured was exercise hypertension, defined as a peak systolic BP > or =210 mm Hg in men and > or =190 mm Hg in women. Thallium perfusion defects were described as: (1) any perfusion abnormality, (2) reversible abnormalities, and (3) any abnormality in > or =3 of 12 myocardial segments ("extensive abnormalities"). Exercise hypertension was present in 1,319 subjects (39%). Patients with exercise hypertension were less likely to have any thallium perfusion abnormality (16% vs 25%, odds ratio [OR] 0.58, 95% confidence intervals [CI] 0.49 to 0.69, p <0.001), reversible thallium abnormalities (7% vs 12%, OR 0.71, 95% CI 0.57 to 0.90, p <0.001), and extensive abnormalities (8% vs 14%, OR 0.53, 95% CI 0.42 to 0.67, p <0.001). After adjusting for possible confounders, the same trend was seen. During 6 years of follow-up there were 283 deaths with no association between exercise hypertension and mortality risk. Thus, exercise hypertension is associated with a lower likelihood of myocardial perfusion abnormalities and is not associated with an increased mortality rate.

Anticipatory blood pressure response to exercise predicts future high blood pressure in middle-aged men

Increases in blood pressure during the period of emotional arousal attendant to impending exertion are well documented, yet the etiologic significance of these elevations is unknown. Research suggests that exaggerated cardiovascular responses to psychological stress may be importantly related to hypertension. We examined blood pressure reactivity in anticipation of an exercise stress test in relation to future hypertension in the Kuopio Ischemic Heart Disease Risk Factor Study, a population-based study of middle-aged men from Eastern Finland. Subjects were 508 unmedicated men with resting blood pressure less than 165/95 mm Hg who completed a bicycle ergometer stress test at baseline and whose hypertensive status was assessed at 4 years of follow-up. Systolic and diastolic reactivity were calculated as the difference between blood pressure measured after seated rest on the bicycle ergometer before initiation of exercise and mean seated resting blood pressure measured 1 week earlier. Logistic regression models adjusted for age and resting blood pressure revealed a graded association between quartiles of reactivity and risk of subsequent hypertension ( > or = 165/95 mm Hg), with men showing systolic responses greater than or equal to 30 mm Hg or diastolic responses greater than 15 mm Hg at nearly four times the risk of becoming hypertensive (odds ratios, 3.80 [95% confidence interval, 1.90 to 7.63] and 3.65 [95% confidence interval, 1.86 to 7.17], respectively) relative to the least-reactive groups (systolic response, < 10 mm Hg; diastolic response, < 5 mm Hg). Adjustments for traditional risk factors for hypertension did not alter these associations. Results demonstrate the clinical significance of the pressor response in anticipation of exercise and support the hypothesis that cardiovascular reactivity to psychological challenge plays a role in the etiology of hypertension.

Cognitive function and cardiovascular responsivity in subjects with a parental history of hypertension

College-age subjects with and without a parental history of hypertension completed a battery of tests of cognitive function on two separate occasions. Pulse rate and blood pressure were measured during performance of each task. In one session, subjects were told that their performance was being evaluated and videotaped from behind an observation mirror (Evaluation Condition). In the other session, subjects were told that their performance was not being observed (Nonevaluation Condition). Regardless of Evaluation Condition, Parental History subjects exhibited slower search of short-term memory than Non-Family History subjects during the first but not the second testing session. Parental History subjects displayed greater elevations in pulse rate than Nonparental History subjects during task performance. The results were interpreted as providing evidence that pathophysiological mechanisms associated with essential hypertension are not the only viable explanations of lower levels of cognitive performance exhibited by hypertensive subjects.

Laboratory reactivity assessment: effects of casual blood pressure status and choice of task difficulty

In a study of 60 healthy young men, 26 with high and 34 with normal casual systolic pressure, blood pressure and its underlying hemodynamic determinants were measured at rest and during exposure to a series of laboratory tasks. Subjects were given a choice of performing either a difficult or an easy version of a mental arithmetic task, and then offered a similar choice of an easy or difficult stimulated public speaking task. All subjects were given the same tasks, regardless of choice, but led to believe the tasks were the ones they had chosen. During all tasks, subjects with high casual systolic pressure showed greater blood pressure, cardiac output, heart rate and myocardial contractility increases than subjects with normal casual pressure. Within the high casual pressure group, subjects who chose difficult for the mental arithmetic task exhibited greater increases in systolic pressure and heart rate during that task than subjects who chose easy. This subgroup maintained their greater responses during a subsequent mental arithmetic task in which all subjects were told that the difficulty level was the reverse of what they had initially chosen. Choosing difficult on the speaking task was associated with greater increases in cardiac output during performance on that task. Differences in cardiovascular responses associated with choice of difficulty were not evident during performance on tasks which did not pertain to the choice. For mental arithmetic, choice of difficulty was also associated with the psychological trait, fear of failure. These findings are relevant to the development of cardiovascular reactivity assessment procedures, which should attempt to detect psychological as well as physiological determinants of individual differences.

Cardiac autonomic mechanisms associated with borderline hypertension under varying behavioral demands: evidence for attenuated parasympathetic tone but not for enhanced beta-adrenergic activity

Elevated blood pressure in psychophysiological studies of borderline hypertension is frequently attributed to the effects of increased sympathetic tone, and with few exceptions, the potential parasympathetic contributions have not been considered. Furthermore, of the investigations that have addressed vagal influences upon blood pressure, most have employed invasive pharmacological assessment of parasympathetic tone. In this study, cardiac parasympathetic and beta-adrenergic influences in borderline hypertension were evaluated noninvasively employing respiratory sinus arrhythmia as a vagal index and preejection period as a sympathetic index of cardiac functioning. Subjects were 30 borderline hypertensive and 23 normotensive males (age range, 24-45 years). The ECG, blood pressure, impedance cardiography, and respiration were measured during two baselines (initial and post-task), a memory-comparison reaction time task, the cold pressor, and CO2-rebreathing. Results indicated tonic differences between groups in all cardiovascular variables across tasks, with the exception of pre-ejection period, which showed no group effects at all. Hypertensives additionally manifested somewhat heightened systolic blood pressure reactivity and attenuated cardiac parasympathetic responsivity to specific tasks. Our findings provide no support for an exaggerated cardiac beta-adrenergic tonic level or reactivity in borderline hypertensives. On the other hand, the consistently lower magnitude of respiratory sinus arrhythmia in our hypertensives suggests that reduced parasympathetic control may be involved in the pathophysiology of hypertension.

Posture, place, and mood effects on ambulatory blood pressure

Ambulatory blood pressure was studied as a function of posture, place, and mood in 131 subjects classified according to race, gender, and hypertensive status. The effect of posture was significant and explained a substantial proportion of within-subject variability. After controlling for posture, significant place and mood effects were observed when subjects were sitting but not when they were standing. Home vs. work differences in both systolic and diastolic blood pressure were significantly greater in Whites than in Blacks. Similar differences in systolic blood pressure were greater in mild hypertensive than in normotensive subjects. The results of this study underscore the need to control for effects of posture when interpreting ambulatory blood pressure readings.

Cardiovascular reactivity to the cold pressor test as a predictor of hypertension

Cardiovascular reactivity to stress is hypothesized to be a marker for subsequent neurogenic cardiovascular disease, but few prospective studies of this hypothesis are available. We studied 910 white male medical students who had their blood pressure and pulse rate measured before and during a cold pressor test in the years 1948-1964. Hypertensive status (requiring drug treatment) was ascertained by annual questionnaires in the 20- to 36-year follow-up period. An association was observed between maximum change in systolic blood pressure and later hypertension, with a cumulative incidence of hypertension by age 44 of 6.7%, 3.0%, and 2.4% for a change in systolic blood pressure in the upper, middle two, and lowest quartiles, respectively (Kaplan-Meier, p less than 0.02). After adjustment for study entry age, Quetelet Index, cigarette smoking, pretest systolic blood pressure, and paternal or maternal history of hypertension in a Cox model, the association persisted. The excess risk associated with systolic blood pressure reactivity was not apparent until the population aged some 20 years and was most apparent among those in whom hypertension developed before age 45 (relative risk = 2.5, 95% confidence intervals = 1.47, 4.71 for a 20 mm Hg change). Diastolic blood pressure and heart rate changes were not associated with later hypertension. These data suggest that persons prone to later hypertension manifest an altered physiology at a young age.

Reporting of life events, family history of hypertension, and cardiovascular activity at rest and during psychological stress

This study investigated whether relations between stressful life events and cardiovascular activity obtained during periods of rest and stress varied as a function of family history of hypertension. Within the family history of hypertension group, males exhibited a positive association between the number of negative avoidable events and resting systolic blood pressure, whereas an inverse association between these two variables was obtained for females. Among females with a family history of hypertension, inverse associations between resting diastolic blood pressure and the subjective effects of life event and number of avoidable events were obtained. Analyses revealed that diastolic blood pressure reactivity to stress was associated with those persons with a family history of hypertension who reported fewer negative life events and less subjective effects for these events.

Graded mental arithmetic as an active psychological challenge

A computer-operated mental arithmetic task is outlined which presents questions at a level of difficulty continuously determined by subjects' accuracy of response on the previous question. The programme incorporates 5 levels of difficulty, and all questions concern the addition or subtraction of two numbers which vary in digit-span according to the current level of difficulty. Response requirements are manual rather than verbal so that, in addition to monitoring heart rate, subjects' exhaled air may be collected throughout the task in order to determine oxygen consumption.