Cardiovascular reactivity to psychosocial stressors. A review of the effects of beta-blockade

Psychophysiological Stress Reactivity in Monozygotic Twins with and without Takotsubo Syndrome

Objective: Takotsubo syndrome (TTS) is characterized by transient left ventricular dysfunction, often elevated myocardial enzymes, and electrocardiographic changes. Previous studies suggested that an overstimulation of the sympathetic nervous system might cause TTS. However, the pathogenesis of TTS is largely unknown. Therefore, we investigated physiological stress reactivity with a standardized stress test in monozygotic twin sisters, only one of whom had experienced TTS. Methods: The 60-year-old Caucasian monozygotic twins, one with and one without a previous episode of TTS, were recruited in the Department of Cardiology at the University Hospital Zurich, Switzerland. We applied the Trier Social Stress Test (TSST) to investigate stress reactivity six weeks after the TTS. Hemodynamic measures (heart rate (HR), blood pressure (BP)), heart rate variability (HRV), plasma norepinephrine and epinephrine and salivary cortisol levels were collected immediately before and after the TSST, and 15, 45, and 90 min after TSST. The monozygotic twins differed in their hemodynamic stress response with the TTS twin showing blunted HR and BP reactivity and vagal withdrawal beyond the acute phase of stress. In contrast, the TTS twin showed a higher catecholamine and cortisol stress response with a steady increase in norepinephrine during the recovery period from stress compared to her non-TTS twin sister. Conclusion: Large studies applying a case-control design are needed to confirm blunted hemodynamic reactivity, increased catecholamine reactivity, vagal withdrawal, and increased cortisol reactivity to stress in TTS. This may advance the knowledge of psychophysiological mechanisms in TTS.

Subjective and physiological responses to the 35% carbon dioxide challenge in healthy and non-clinical control populations: a meta-analysis and systematic review

BACKGROUND/RATIONALE

The carbon dioxide (CO₂) challenge has been reliably used in laboratory settings as a panicogen in clinical populations. However, the magnitude of these effects on healthy and non-clinical control populations are not clear. The aim of this meta-analysis and systematic review is to provide quantitative estimates of those effects. Specifically, the current paper will evaluate the relative efficacy of the CO₂ challenge in eliciting both subjective and physiological arousal in healthy and non-clinical control populations.

METHOD

A total of 16 articles with 35 independent samples were included in the meta-analysis, while 37 studies with 74 independent samples were included in the systematic review.

RESULTS

Both the meta-analysis and systematic review found the CO₂ challenge to elicit an increase in subjective distress via self-reported anxiety and fear. Physiological responses via blood pressure and heart rate were heterogeneous in studies sampled, with no significant changes observed across studies. Moderator analyses revealed the variations in findings may be attributed to participant screening and invasive sampling.

DISCUSSION

Findings highlight the CO₂ challenge as a useful tool in the provocation of subjective distress. Implications for both the use of the CO₂ challenge and its anticipated effects in healthy and non-clinical control populations are discussed.

The effect of pet therapy on the physiological and subjective stress response: A meta-analysis

Studies have reported that exposure to pet therapy (PT) can reduce physiological and subjective stress and anxiety levels. The aim of this meta-analysis is to examine the efficacy of PT as a method for reducing physiological stress levels (blood pressure and heart rate) and subjective stress and anxiety scores (self-reported stress/anxiety). Further, we examined the effects of sample characteristics and modifications to the PT (different age groups and health status of participants across samples, whether a stressor was present, and individual versus group PT) as potential moderators of the relationship between PT and stress reactivity. Our searches incorporated articles published from May 2017 and earlier in PsycINFO, MEDLINE, and PubMed. This meta-analysis included 28 articles with 34 independent samples and contained a total of 1,310 participants. Using a random effects model, we determined that significant differences occurred in heart rate, self-reported anxiety, and self-reported stress after PT exposure compared with before PT. However, we did not detect significant differences in blood pressure after PT. Sample characteristics and modifications to the PT significantly moderated the effect of PT on stress responses. Our results suggest that PT can be an effective program for reducing stress reactivity.

Cardiovascular reactions to psychological stress and abuse history: the role of occurrence, frequency, and type of abuse

BACKGROUND AND OBJECTIVES

Extreme cardiovascular reactions to psychological stress have been associated with traumatic life experiences. Previous studies have focused on the occurrence or frequency of abuse rather than type of abuse. We examined how occurrence, frequency, and the type of abuse history are related to cardiovascular reactivity (CVR) to acute psychological stress.

DESIGN

The study consisted of between group and continuous analyses to examine the association between occurrence, type, and frequency of abuse with cardiovascular reactions to acute psychological stress.

METHODS

Data from 64 participants were collected. Heart rate, systolic blood pressure, and diastolic blood pressure were measured at baseline and during a standard mental arithmetic stress task.

RESULTS

Individuals who experienced abuse showed diminished CVR to acute psychological stress; this was driven specifically by the history of sexual abuse. Frequency of abuse did not relate to stress reactions.

CONCLUSIONS

These findings accord with previous work suggesting a relationship between traumatic life experience and hypoarousal in physiological reactivity and extend previous findings by suggesting the relationship may be driven by sexual abuse.

Labile and Paroxysmal Hypertension: Common Clinical Dilemmas in Need of Treatment Studies

Although "labile hypertension" is regularly encountered by clinicians, there is a paucity of information available to guide therapeutic decisions. This review discusses its clinical relevance, the limitations of current knowledge, and possible directions for future research and clinical management. Results of studies that assessed measures of blood pressure variability or reactivity are reviewed. The limited information about effects of antihypertensive drugs on blood pressure variability is discussed. Two different clinical presentations are differentiated: labile hypertension and paroxysmal hypertension. Labile hypertension remains a clinical impression without defined criteria or treatment guidance. Paroxysmal hypertension, also called pseudopheochromocytoma, presents as dramatic episodes of abrupt and severe blood pressure elevation. The disorder can be disabling. Although it regularly raises suspicion of a pheochromocytoma, such a tumor is found in <2 % of patients. The cause, which involves both emotional factors and the sympathetic nervous system, and treatment approaches, are presented.

Noradrenaline effects on social behaviour, intergroup relations, and moral decisions

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The involvement of noradrenaline in moral and social judgments is reviewed.

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Noradrenergic transmission is causally involved in implicit racial biases, racial face perception, as well as increasing social harm aversion.

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Fear and anger – mediated by limbic circuit brain activation – might mediate moral and social decisions and acts.

Recent research has begun to elucidate the neural basis of higher order social concepts, such as the mechanisms involved in intergroup relations, and moral judgments. Most theories have concentrated on higher order emotions, such as guilt, shame, or empathy, as core mechanisms. Accordingly, psychopharmacological and neurobiological studies have investigated the effects of manipulating serotonin or oxytocin activity on moral and social decisions and attitudes. However, recently it has been determined that changes in more basic emotions, such as fear and anger, might also have a significant role in social and moral cognition. This article summarizes psychopharmacological and fMRI research on the role of noradrenaline in higher order social cognition suggesting that indeed noradrenergic mediated affective changes might play key – and probably causal – role in certain social attitudes and moral judgments. Social judgments may also be directly influenced by numerous neurotransmitter manipulations but these effects could be mediated by modulation of basic emotions which appear to play an essential role in the formation of social concepts and moral behaviour.

Heart rate complexity: A novel approach to assessing cardiac stress reactivity

Correlation dimension (D2), a measure of heart rate (HR) complexity, has been shown to decrease in response to acute mental stress and relate to adverse cardiovascular health. However, the relationship between stress-induced changes in D2 and HR has yet to be established. The present studies aimed to assess this relationship systematically while controlling for changes in respiration and autonomic activity. In Study 1 (N = 25) D2 decreased during stress and predicted HR reactivity even after adjusting for changes in respiration rate, and cardiac vagal tone. This result was replicated in Study 2 (N = 162) and extended by including a measure of cardiac sympathetic activity; correlation dimension remained an independent predictor of HR reactivity in a hierarchical linear model containing measures of cardiac parasympathetic and sympathetic activity and their interaction. These results suggest that correlation dimension may provide additional information regarding cardiac stress reactivity above that provided by traditional measures of cardiac autonomic function.

Hostility and physiological responses to acute stress in people with type 2 diabetes

OBJECTIVE

Hostility is associated with cardiovascular mortality and morbidity, and one of the mechanisms may involve heightened reactivity to mental stress. However, little research has been conducted in populations at high risk for cardiovascular disease. The aim of the present study was to assess the relationship between hostility and acute stress responsivity in individuals with Type 2 diabetes.

METHODS

A total of 140 individuals (median age [standard deviation] 63.71 [7.00] years) with Type 2 diabetes took part in laboratory-based experimental stress testing. Systolic blood pressure, diastolic blood pressure, heart rate, plasma interleukin-6 (IL-6), and salivary cortisol were assessed at baseline, during two stress tasks, and 45 and 75 minutes later. Cynical hostility was assessed using the Cook Medley Cynical Hostility Scale.

RESULTS

Participants with greater hostility scores had heightened increases in IL-6 induced by the acute stress tasks (B = 0.082, p = .002), independent of age, sex, body mass index, smoking, household income, time of testing, medication, and baseline IL-6. Hostility was inversely associated with cortisol output poststress (B = -0.017, p = .002), independent of covariates. No associations between hostility and blood pressure or heart rate responses were observed.

CONCLUSIONS

Hostile individuals with Type 2 diabetes may be susceptible to stress-induced increases in inflammation. Further research is needed to understand if such changes increase the risk of cardiovascular disease in this population.

Beta adrenergic blockade reduces utilitarian judgement

Noradrenergic pathways are involved in mediating the central and peripheral effects of physiological arousal. The aim of the present study was to investigate the role of noradrenergic transmission in moral decision-making. We studied the effects in healthy volunteers of propranolol (a noradrenergic beta-adrenoceptor antagonist) on moral judgement in a set of moral dilemmas pitting utilitarian outcomes (e.g., saving five lives) against highly aversive harmful actions (e.g., killing an innocent person) in a double-blind, placebo-controlled, parallel group design. Propranolol (40 mg orally) significantly reduced heart rate, but had no effect on self-reported mood. Importantly, propranolol made participants more likely to judge harmful actions as morally unacceptable, but only in dilemmas where harms were ‘up close and personal’. In addition, longer response times for such personal dilemmas were only found for the placebo group. Finally, judgments in personal dilemmas by the propranolol group were more decisive. These findings indicate that noradrenergic pathways play a role in responses to moral dilemmas, in line with recent work implicating emotion in moral decision-making. However, contrary to current theorising, these findings also suggest that aversion to harming is not driven by emotional arousal. Our findings are also of significant practical interest given that propranolol is a widely used drug in different settings, and is currently being considered as a potential treatment for post-traumatic stress disorder in military and rescue service personnel.

Baroreflex sensitivity is higher during acute psychological stress in healthy subjects under β-adrenergic blockade

Acute psychological stress challenges the cardiovascular system with an increase in BP (blood pressure), HR (heart rate) and reduced BRS (baroreflex sensitivity). β-adrenergic blockade enhances BRS during rest, but its effect on BRS during acute psychological stress is unknown. This study tested the hypothesis that BRS is higher during acute psychological stress in healthy subjects under β-adrenergic blockade. Twenty healthy novice male bungee jumpers were randomized and studied with (PROP, n=10) or without (CTRL, n=10) propranolol. BP and HR responses and BRS [cross-correlation time-domain (BRSTD) and cross-spectral frequency-domain (BRSFD) analysis] were evaluated from 30 min prior up to 2 h after the jump. HR, cardiac output and pulse pressure were lower in the PROP group throughout the study. Prior to the bungee jump, BRS was higher in the PROP group compared with the CTRL group [BRSTD: 28 (24-42) compared with 17 (16-28) ms·mmHg-1, P<0.05; BRSFD: 27 (20-34) compared with 14 (9-19) ms·mmHg-1, P<0.05; values are medians (interquartile range)]. BP declined after the jump in both groups, and post-jump BRS did not differ between the groups. In conclusion, during acute psychological stress, BRS is higher in healthy subjects treated with non-selective β-adrenergic blockade with significantly lower HR but comparable BP.

The clinical spectrum of labile hypertension: a management dilemma

J Clin Hypertens (Greenwich). 2009;11:491-497. (c)2009 Wiley Periodicals, Inc.Although the management of the labile component of blood pressure elevation is a problem often encountered by clinicians, there is a paucity of information available to guide therapeutic decisions. This review discusses the clinical relevance of blood pressure lability, the limitations of current knowledge, and possible directions for future research and clinical management.

Hostility and physiological responses to laboratory stress in acute coronary syndrome patients

OBJECTIVE

Evidence suggests that emotional stress can trigger acute coronary syndromes in patients with advanced coronary artery disease (CAD), although the mechanisms involved remain unclear. Hostility is associated with heightened reactivity to stress in healthy individuals, and with an elevated risk of adverse cardiac events in CAD patients. This study set out to test whether hostile individuals with advanced CAD were also more stress responsive.

METHODS

Thirty-four men (aged 55.9+/-9.3 years) who had recently survived an acute coronary syndrome took part in laboratory testing. Trait hostility was assessed by the Cook Medley Hostility Scale, and cardiovascular activity, salivary cortisol, and plasma concentrations of interleukin-6 were assessed at baseline, during performance of two mental tasks, and during a 2-h recovery.

RESULTS

Participants with higher hostility scores had heightened systolic and diastolic blood pressure (BP) reactivity to tasks (both P<.05), as well as a more sustained increase in systolic BP at 2 h post-task (P=.024), independent of age, BMI, smoking status, medication, and baseline BP. Hostility was also associated with elevated plasma interleukin-6 (IL-6) levels at 75 min (P=.023) and 2 h (P=.016) poststress and was negatively correlated with salivary cortisol at 75 min (P=.034).

CONCLUSION

Hostile individuals with advanced cardiovascular disease may be particularly susceptible to stress-induced increases in sympathetic activity and inflammation. These mechanisms may contribute to an elevated risk of emotionally triggered cardiac events in such patients.

Psychophysiological and cortisol responses to psychological stress in depressed and nondepressed older men and women with elevated cardiovascular disease risk

OBJECTIVE

The objective of this study was to compare psychophysiological and cortisol reactions to psychological stress in older depressed and nondepressed patients at risk for cardiovascular disease (CVD).

METHODS

Forty-eight depressed participants and 20 controls with elevated cardiovascular risk factors underwent a psychological stress test during which cardiovascular variables were measured. Salivary cortisol was collected after each test segment. Traditional (e.g., lipids) and atypical (e.g., C-reactive protein) CVD risk factors were also obtained.

RESULTS

At baseline, the groups did not differ on lipid levels, flow-mediated vasodilation, body mass index, or asymmetric dimethylarginine. However, the depressed patients had significantly higher C-reactive protein levels. Contrary to our hypothesis, there were no differences in baseline cortisol levels or diurnal cortisol slopes, but depressed patients showed significantly lower cortisol levels during the stress test (p = .03) and less cortisol response to stress. Compared with nondepressed subjects, depressed subjects also showed lower levels of respiratory sinus arrhythmia (RSA(TF)) during the stress test (p = .02).

CONCLUSIONS

In this sample, older depressed subjects with elevated risk for CVD exhibited a hypocortisol response to acute stress. This impaired cortisol response might contribute to chronic inflammation (as reflected in the elevated C-reactive proteins in depressed patients) and in other ways increase CVD risk. The reduced RSA(TF) activity may also increase CVD risk in depressed patients through impaired autonomic nervous system response to cardiophysiological demands.

Blood pressure reactivity to stress is better for people who recently had penile–vaginal intercourse than for people who had other or no sexual activity

Penile-vaginal intercourse (PVI) but not other sexual behavior is associated with better psychological and physiological function. I examined the relationship of sexual behavior patterns to blood pressure (BP) and its reactivity to stress (public speaking and verbal arithmetic). For a fortnight, 24 women and 22 men used daily diaries to record PVI, masturbation, and partnered sexual behavior in the absence of PVI. Persons who reported PVI (but no other sexual activities) had better stress response (less reactivity and/or lower baseline levels) than persons reporting other or no sexual behaviors. Persons who only masturbated or had partnered sex without PVI had 14 mmHg more systolic BP reactivity than those who had PVI but not the other behaviors. Many variables were examined but failed to confound the observed relationships. The magnitude of the sexual behavior effect on BP reactivity is greater than of other factors in the literature. These findings add to the research corpus on the benefits of PVI (differentiated from other sexual activities).

Subchronic treatment with amino acid mixture of L-lysine and L-arginine modifies neuroendocrine activation during psychosocial stress in subjects with high trait anxiety

The aim of the present study was to evaluate possible modulatory effect of the treatment with L-lysine and L-arginine on neuroendocrine activation during psychosocial stress in healthy subjects with relatively high trait anxiety in a randomized, double blind placebo controlled trial. In 29 healthy subjects at the upper limit of the normal range of a trait anxiety scale, a mixture of L-lysine and L-arginine (3 g each/day) was administered for 10 days followed by exposure to a psychosocial stress procedure based on public speech. Hormone levels, cardiovascular activation and skin conductance were measured. Amino acid treatment resulted in enhanced adrenocorticotropic hormone, cortisol, adrenaline and noradrenaline levels and galvanic skin responses during stress compared to those in placebo-treated group. Increases in the heart rate and blood pressure in response to public speaking task were not influenced by amino acid treatment. Results of the present study support the hypothesis that L-lysine in combination with L-arginine, which may induce anxiolytic effects, modify hormonal responses during psychosocial stress in humans. Such action may represent a normalization of hormone levels to the pattern observed previously in subjects with low trait anxiety.

Exaggerated platelet and hemodynamic reactivity to mental stress in men with coronary artery disease

OBJECTIVE

This study compared the effects of acute mental stress on cardiovascular and subjective responses and platelet activation in male patients with established coronary artery disease (CAD) and age-matched controls.

METHODS

We assessed 17 male CAD patients aged 44 to 59 years and 22 healthy male controls. Blood pressure, heart rate, and hemodynamics were assessed before, during, and up to 2 hours after administration of color/word and mirror tracing tasks. Blood was sampled at baseline, after tasks, and at 30 and 75 minutes after stress, and platelet activation was assessed by measuring platelet-leukocyte aggregates (PLAs) using flow cytometry.

RESULTS

CAD patients showed significantly greater systolic blood pressure stress responses than controls (mean increases of 43.9 and 28.3 mm Hg, adjusted for income, body mass index, waist/hip ratio, and medication), together with larger increases in heart rate (14.1 and 4.7 bpm) and cardiac index. Total peripheral resistance increased during the poststress recovery period in CAD patients but not in controls. PLAs increased with stress in both groups, but remained elevated at 75 minutes in CAD patients, returning to baseline in controls. Heart rate and cardiac index responses were correlated with increases in subjective stress and with depression ratings, whereas PLA responses were associated with ratings of task difficulty.

CONCLUSION

Acute mental stress stimulated heightened cardiovascular responses in CAD patients, coupled with more prolonged platelet activation. These factors may contribute to plaque rupture and thrombogenesis, and partly mediate stress-induced triggering of acute coronary syndromes.

Cardiovascular reactivity to psychological challenge: conceptual and measurement considerations

OBJECTIVE AND METHODS

This article is a selective review of recent findings bearing on the conceptualization and measurement of cardiovascular reactivity to psychological challenge, with a focus on several issues relevant to the reliability, content validity, construct validity, and criterion validity of these measures.

RESULTS AND CONCLUSIONS

With respect to reliability, use of standardized task demands and aggregated scores are associated with enhanced short-term reliability, but the long-term reliability of cardiovascular reactivity has not been sufficiently documented. With respect to content validity, existing evidence suggests that "vascular" or "cardiac" tasks may evoke responses that reflect similar distributions of individual difference, whereas associations between responses to "physical" and "psychological" tasks are modest. The evidence is not clear at present with respect to the importance of including affective or interpersonal stimuli as part of trait reactivity assessments. With respect to construct validity, existing data show that cardiovascular reactivity to psychological challenge is largely independent of standard measures of autonomic function. With respect to criterion validity, recent studies point to a number of methodological limitations that may have restricted our ability to detect lab-to-life generalizability of reactivity measures in the past. Continued progress in understanding and measuring reactivity as an individual difference dimension is essential in helping us to evaluate emerging evidence examining the relationship between reactivity and disease risk.

Cannabis, tobacco, and caffeine use modify the blood pressure reactivity protection of ascorbic acid

Cannabis, caffeine, and tobacco use are associated with increased mesolimbic dopamine activity. Ascorbic acid (AA) modulates some dopaminergic agent effects, and was recently found to decrease systolic blood pressure (SBP) stress reactivity. To examine how AA SBP stress reactivity protection varies by use of these substances, data from an AA trial (Cetebe, 3000 mg/day for 14 days; N=108) were compared by substance use level regarding SBP reactivity to the anticipation and actual experience phases of a standardized psychological stressor (10 min of public speaking and arithmetic). Self-reported never users of cannabis, persons not currently smoking tobacco, and persons consuming three or more caffeine beverages daily all exhibited AA SBP stress reactivity protection to the actual stressor, but not during the anticipation phase. Conversely, self-reported ever cannabis users, current tobacco smokers, and persons consuming less than three caffeine beverages daily exhibited the AA SBP protection during the anticipation phase, but only the lower caffeine consumption group exhibited AA protection during both phases. Covariates (neuroticism, extraversion, and depression scores, age, sex, body mass index) were all nonsignificant. Results are discussed in terms of dopaminergic effects of these substances, modulation of catecholaminergic and endothelial activity, and AA support of coping styles.

Predictors of pain during invasive medical procedures

This study explored whether cardiovascular response and heart rate response to surgical stress were related to pain during percutaneous transcatheter diagnostic and therapeutic peripheral vascular and renal interventions. One hundred twenty-nine patients, 61 men and 68 women, provided repeated measures of pain on a 0 to 10 scale every 15 minutes during and at the end of the procedure. We tested 2 hypotheses: (1) baseline blood pressure and heart rate predict pain report and (2) initial procedural changes in blood pressure and heart rate predict pain report. Results of regression analysis showed that heart rate response is a significant independent predictor of pain regardless of whether pain is defined as the maximum level during the procedure or as the pain level at the end. Baseline pain, anxiety, and heart rate were significantly correlated to maximum pain report but did not enter the final model as significant independent predictors. We also found that patients whose heart rate increased during surgery from their baseline level had significantly lower pain report than those who did not show an increase. Neither baseline blood pressure nor blood pressure changes were significant predictors of pain level. Thus, we concluded that heart rate response is a powerful negative predictor of procedural pain even after controlling for baseline variables, type of procedure, and units of pain medication.

Psychological characteristics and responses to antihypertensive drug therapy

The objective of this study was to explore the relationship between psychological characteristics and responses to antihypertensive drug therapy. Twenty-two hypertensive subjects underwent psychological evaluation and treatment with 1) a diuretic, hydrochlorothiazide (HCTZ); 2) an angiotensin-converting enzyme (ACE) inhibitor, quinapril; and 3) combined alpha + beta blockade (doxazosin + betaxolol). Anger-Out scores on the State-Trait Anger Expression Inventory were positively correlated with the HCTZ-induced fall in systolic blood pressure (p<0.01); Anger-In was negatively correlated with the quinapril-induced fall in systolic pressure (p<0.05). The target systolic blood pressure (130 mm Hg) was achieved with either HCTZ or quinapril in 79% of subjects without, vs. 25% of subjects with, childhood trauma (p=0.03). Responses to doxazosin + betaxolol were not correlated with psychological characteristics. The authors conclude that both inhibited anger expression and childhood trauma are associated with reduced response to a diuretic or ACE inhibitor. Combined alpha/beta blockade may be preferable to an ACE inhibitor or diuretic in treating selected hypertensive patients. Further studies should include examination of psychological factors in terms of the response to combined ACE inhibitor + diuretic therapy.

Cardiovascular reactivity to mental stress in the Stockholm Female Coronary Risk Study

OBJECTIVE

This study evaluated the ability of mental stress testing to discriminate between women with and without CHD, and among women with different disease manifestations, taking into account history of hypertension and beta-blocker use.

METHODS

Analyses were based on data from a community-based case-control study of women aged 65 years or younger. The study group consisted of 292 women who were hospitalized for an acute event of CHD, either AMI or unstable AP in Stockholm between 1991 and 1994. Controls were matched to cases by age and catchment area. Cardiovascular reactivity and emotional response to an anagram task solved under time pressure were measured 3 to 6 months after hospitalization.

RESULTS

Patients reacted with smaller increases in heart rate (4 bpm) than their controls (7 bpm). Results for the rate-pressure product were similar. Cardiovascular reactions did not distinguish patients with AP from those with AMI. History of hypertension (present in 50% of patients and 11% of controls) was related to enhanced diastolic blood pressure reactivity. Patients on beta-blockers (66%) had lower heart-rate levels throughout testing, but did not differ in their cardiovascular stress reactions when compared with the remaining participants.

CONCLUSIONS

Women with heart disease have somewhat lower heart-rate responses to stress than healthy age-matched controls. History of hypertension is related to enhanced diastolic blood pressure reactivity to mental stress in both patients and controls.

Pet Ownership, but Not ACE Inhibitor Therapy, Blunts Home Blood Pressure Responses to Mental Stress

In the present study, we evaluated the effect of a nonevaluative social support intervention (pet ownership) on blood pressure response to mental stress before and during ACE inhibitor therapy. Forty-eight hypertensive individuals participated in an experiment at home and in the physician’s office. Participants were randomized to an experimental group with assignment of pet ownership in addition to lisinopril (20 mg/d) or to a control group with only lisinopril (20 mg/d). On each study day, blood pressure, heart rate, and plasma renin activity were recorded at baseline and after each mental stressor (serial subtraction and speech). Before drug therapy, mean responses to mental stress did not differ significantly between experimental and control groups in heart rate (94 [SD 6.8] versus 93 [6.8] bpm), systolic blood pressure (182 [8.0] versus 181 [8.3] mm Hg), diastolic blood pressure (120 [6.6] versus 119 [7.9] mm Hg), or plasma renin activity (9.4 [0.59] versus 9.3 [0.57] ng · mL −1 · h −1 ). Lisinopril therapy lowered resting blood pressure by ≈35/20 mm Hg in both groups, but responses to mental stress were significantly lower among pet owners relative to those who only received lisinopril ( P <0.0001; heart rate 81 [6.3] versus 91 [6.5] bpm, systolic blood pressure 131 [6.8] versus 141 [7.8] mm Hg, diastolic blood pressure 92 [6.3] versus 100 [6.8] mm Hg, and plasma renin activity 13.9 [0.92] versus 16.1 [0.58] ng · mL −1 · h −1 ). We conclude that ACE inhibitor therapy alone lowers resting blood pressure, whereas increased social support through pet ownership lowers blood pressure response to mental stress.

Descriptive epidemiology of blood pressure response to change in body position. The ARIC study

The epidemiology of a common measure of cardiovascular reactivity, the change in systolic blood pressure (DeltaSBP) from the supine to the standing position, is described in a cohort of 13 340 men and women aged 45 to 65 years enrolled in the Atherosclerosis Risk in Communities (ARIC) Study. The distribution of DeltaSBP was found to be symmetrical and unimodal, with a mean value near zero (-0.45 mm Hg). The range of DeltaSBP was from -63.2 to 54.3 mm Hg, and the standard deviation was 10.8. Stratification of DeltaSBP by race and gender shows a slight shift in distribution toward higher values for black men and women. DeltaSBP was categorized into deciles. Participants in the top 30% and bottom 30% of the distribution were compared with individuals in the middle 40% of the distribution, who had little or no change in SBP on standing. Participants in the bottom 30% (ie, SBP decreased on standing) were significantly older, had a greater prevalence of hypertension and peripheral vascular disease, had higher values of SBP, and had more cigarette-years of smoking. Among participants in the top 30% (ie, SBP increased on standing), a significantly larger proportion were black, mean seated SBP was higher, and the predicted risk of developing coronary heart disease after 8 years was greater. The response of SBP to change in posture showed considerable variability in a population sample of middle-aged adults. Cardiovascular morbidity, sociodemographic factors, and cigarette smoking were associated with the magnitude and direction of the postural change.

Cardiovascular and immune responses to acute psychological stress in young and old women: a meta-analysis

OBJECTIVE

To describe the relationships between cardiovascular and natural killer (NK) cell number changes on acute psychological stress in women.

METHOD

Data from eight different studies were analyzed. A total of 128 healthy female subjects, 85 younger (18-45 years) and 43 older (49-87 years), had been subjected to a speech stressor (N = 80) or a mental effort stressor (N = 48), mental arithmetic, or the Stroop test. Correlations between changes in NK cell numbers, systolic (SBP) and diastolic (DBP) blood pressure, and heart rate (HR) were computed. Meta-analysis programs were used to study correlations across studies and to examine whether correlations differed with stressors or age.

RESULTS

In all studies, significant increases over baseline were observed for each variable. Across studies, the mean weighted r between changes in HR, DBP, and SBP was medium (rw = .25) to large (rw = .64). A medium to large average correlation between HR and NK changes (rw = .37) was observed, whereas average correlations of changes in NK cell numbers with blood pressure changes were small to medium (rw < or = .23). Correlations between changes in NK cell numbers and cardiovascular variables were homogeneous across studies, whereas mutual correlations between cardiovascular variables were heterogeneous. One moderator variable showed itself: correlations between HR and DBP reactions were larger in studies with older than younger subjects.

CONCLUSION

NK cell changes and HR responses induced by acute stress in women are regulated, to some extent, by the same mechanisms. Neither the type of stressor nor age seem to be very important when considering correlations between NK cell and cardiovascular changes. This study integrates information about NK cell and cardiovascular responses in women that can be used as reference material in future studies.

Talking effect and white coat phenomenon in hypertensive patients

Both white coat effect (the tendency of blood pressure to rise during a medical visit) and talking effect were analyzed in 42 patients with essential hypertension. Blood pressure was measured during the clinic visit and over the subsequent 24-hour ambulatory period, with the physician performing 49 +/- 4 measurements for each patient. Three silent periods and two talking periods (stress and relaxation) were randomly allocated in a crossover design and studied, using analysis of variance. During the initial 11-minute silent period, systolic/diastolic blood pressures increased by 6 mm Hg/5 mm Hg. During the subsequent talking periods, these variations were significantly greater: +22 mm Hg/+17 mm Hg. Measures of systolic/diastolic blood pressure were higher during stressful talking than during relaxed talking. The talking and its emotional contents seemed to explain 70% of the white coat phenomenon. To minimize the white coat phenomenon in the clinic, physicians, nurses, and clinicians are advised to measure blood pressure during an initial period of silence.

Is aspirin, as used for antithrombosis, an emotion-modulating agent?

Antiplatelet substances, generally aspirin, have become widely used for secondary prevention of ischemic heart disease. Used in relatively small doses, it is generally assumed that aspirin has no psychoactive effect. The present study took advantage of a sample of 174 males undergoing coronary angiography to see if regular aspirin use as prophylactic therapy for ischemic heart disease was associated with one or more of a number of measures of emotional distress. Aspirin use was found to be associated with less depression and anxiety or worry, as reported by the patient and as perceived by a significant other. Despite a significant association of aspirin use with the presence of documented coronary artery disease, the association of aspirin use and diminished distress could not be accounted for by the previously observed high prevalence of depressed/anxious individuals among patients with negative or nominal results on angiography, or by a number of other demographic or clinical variables such as age and socioeconomic status. Although only correlational in nature, present results raise the question of whether aspirin may have a beneficial mood-modulating effect.

Relationships between cardiovascular and immunological changes in an experimental stress model

To investigate the relationships between cardiovascular variables (SBP, DBP, and HR) and circulating natural killer (NK) cell numbers, 70 male volunteers were subjected to a rest condition (N = 30) or a stressful laboratory task (N = 40). At baseline, no significant relationships could be demonstrated between the number of NK cells and the cardiovascular variables. Analysis of covariance showed that the stressor induced increases in the number of NK cells, SBP, DBP, and HR. Changes in Nk cell numbers were highly correlated to changes in cardiovascular variables in both the task and the no-task group. These results indicate that there is no relationship between the number of circulating NK cells and cardiovascular levels per se, but that changes in these variables, either stress-induced or under rest conditions, are regulated by a common mechanism.

Effects of beta-adrenergic blockade on immunologic and cardiovascular changes induced by mental stress

BACKGROUND

Acute mental stress evokes responses in the cardiovascular and the immune systems. In particular, the subset of natural killer (NK) cells is found to be responsive to mental stress. The role of beta-adrenergic mechanisms in these processes in the subject of this investigation.

METHODS AND RESULTS

Healthy male volunteers (n = 31) were subjected to two consecutive mental tasks. Subjects were randomly assigned to a beta-blocker (propranolol 40 mg) or a placebo group. The capsules were ingested 1 hour before the tasks. The tasks evoked sympathetic responses, as indicated by an increase in heart rate and a decrease in the preejection period. These effects were abolished under beta-blockade, indicating that effective beta-blockade was achieved. In the immune system, significant increases were found for the number of NK cells and NK cell activity in the placebo group; these increases were absent in the propranolol group. In addition, an increase in all lymphocyte subsets was observed in subjects who had ingested propranolol. This increase, however, was also observed in subjects who had received propranolol but had not performed the tasks, indicating that these non-subset-specific increases in lymphocytes were a side effect of the beta-blocker.

CONCLUSIONS

Mental stress induces activation of the sympathetic nervous system, with concomitant increases in the number of NK cells in the circulation. These changes were inhibited by propranolol, indicating that stress-induced increases in the number and activity of NK cells in the circulation are controlled by a beta-adrenergic mechanism.

Converting enzyme inhibition and blood pressure reactivity to psychological stressors

There is considerable interest in blood pressure reactivity to psychological stressors. Because the sympathetic nervous system and the renin-angiotensin system are so responsive to stressors and are themselves the targets of many antihypertensive medications, many investigators have wondered if such medications decrease the blood pressure response to stressful stimuli. We studied 25 normotensive and 21 hypertensive men in a double-blind crossover study during which they received either placebo for 4 days or captopril (25 mg b.i.d.) for 4 days while they were hospitalized in a clinical research center. Patients were studied at resting baseline, while performing a mathematics task, and while reading out loud a disturbing newspaper article. Although captopril lowered the resting blood pressure levels, it had no effect on the amplitude of reactivity to stressors.