Hemodynamics of Blood Pressure Responses During Active and Passive Coping

This laboratory study was designed to address a number of interrelated issues regarding cardiovascular reactivity to psychological stress. One objective was to extend the previous research comparing cardiovascular responses during active versus passive coping, by comparing responses to two task conditions designed to be similar in all ways except the opportunity to make a response influencing the task's outcome. A second objective was to compare responses to two different passive film tasks, which differed in outcome uncertainty and the degree of vicarious active coping achieved through identification with the role portrayed by the actors. A third objective was to evaluate whether individuals are predisposed to exhibit a particular hemodynamic pattern underlying their blood pressure adjustments, independently of the task demands imposed. Ninety healthy young adult male subjects were tested in pairs on a series of tasks that included a competitive reaction-time task, an active as well as a passive phase of a team reaction-time task, and passive viewing of two film segments. The tasks demanding active coping responses tended to raise blood pressure due primarily to an increase in cardiac output, while vascular resistance fell. During passive coping demands cardiac output increased to a lesser extent, but vascular resistance also tended to increase, thereby raising blood pressure by their synergistic effects. However, these patterns were not typical of all participating subjects. On the basis of their cardiac output and vascular resistance responses to the competitive reaction-time task, one third of the subjects were categorized as being high myocardial reactors (n = 30) and another third high vascular reactors (n = 31). Post-hoc analyses of responses to the other tasks, based on these categorizations, indicated that the hemodynamic basis of reactivity is an individual characteristic only partially modified by coping demands. The active/passive coping dimension is discussed both conceptually and in relation to the role of stress in the etiology of hypertension.     

Heart Rate Reactivity, Behavior Pattern, and Parental Hypertension as Predictors of Cardiovascular Activity During Cognitive Challenge

Hemodynamic responses were studied during work on serial subtraction and digits backwards tasks in 99 healthy male undergraduates jointly classified as high or low heart rate reactors, Type A or Type B behavior pattern, and as having positive or negative parental history of hypertension. Heart rate, systolic blood pressure, and diastolic blood pressure were recorded, and rate pressure product was calculated at rest and during the tasks. High heart rate reactors to a cold pressor task responded with relatively higher heart rate and rate pressure product during both cognitive tasks than low heart rate reactors. Type A subjects defined by Jenkins Activity Survey did not differ from Type Bs on any of these physiological variables, although behavioral evidence demonstrated greater effort and superior performance by the Type As. Subjects with a positive parental history of hypertension manifested greater systolic and diastolic pressures and rate pressure product responses to the cognitive challenge than those lacking such parental history. These results indicate that the individual difference variables of heart rate reactivity and parental history of hypertension predicted different hemodynamic response patterns to behavioral challenge.     

Anger, harassment, and cardiovascular reactivity among Chinese and Indian men in Singapore

OBJECTIVE: This experiment examined psychological and cardiovascular responses to experimental harassment among Chinese and Indian men in Singapore who differed in levels of dispositional anger. METHODS: Eighty-four Chinese and Indian men participated in a laboratory experiment on cardiovascular reactivity in which mood was rated and heart rate and blood pressure were measured during computer tasks in which they were either harassed or allowed to complete the tasks without interruption. RESULTS: Comparison of systolic reactivity to harassment and nonharassment indicated, as expected, that reactivity was greater after harassment. Furthermore, a significant race by dispositional anger by harassment effect was obtained for systolic reactivity that indicated different patterns of reactivity for Chinese and Indian participants. In the absence of harassment, Chinese participants showed low systolic reactivity regardless of their level of dispositional anger, whereas systolic reactivity increased as a function of dispositional anger when they were harassed. For Indians, however, systolic reactivity was a positive function of dispositional anger both when they were harassed and not harassed. CONCLUSIONS: These results suggest stronger cardiovascular reactivity to stress among Indian than among Chinese men. This seems to be particularly true for Indians high in dispositional anger.     

Psychophysiological correlates of individual differences in patterns of hemodynamic reactivity.

The present study delineates a method for the quantification of six hemodynamic reactivity patterns, in response to a laboratory stressor, and examines the psychophysiological correlates of individual differences in these patterns. One hundred and ninety-four young adult men and women participated in rest periods and two laboratory stressors, mental arithmetic and an anger recall interview. Measures were taken of blood pressure, heart rate, and cardiac output, from which total peripheral resistance was derived, as well as state reports of feelings during the tasks. Six hemodynamic reactor patterns were identified: Non-reactors, Mild Myocardials, Mild Vasculars, Myocardials, Vasculars, and Dual Reactors, each associated with a unique profile of cardiac output and total peripheral resistance change. Myocardial reactors to the interview had the highest resting levels of blood pressure and total peripheral resistance. Dual reactors had the largest increases in diastolic reactivity; Dual and Myocardial reactors had the largest increases in systolic reactivity. The extreme reactor groups (Dual, Myocardial, Vascular) all reported greater task invigoration than the Non-reactors, who reported greater efforts to relax. Reactor groups were similar on anger-related trait affect. Based on both resting blood pressure and magnitude of task-induced reactivity, Myocardial and Dual reactors may be at the greatest risk for subsequent hypertension.     

Hemodynamic response patterns: responder type differences in reactivity and recovery

We examined whether responder type groups reflecting patterns of hemodynamic reactivity might also differ in recovery responses. Cardiac output (CO), total peripheral resistance (TPR), systolic and diastolic blood pressure, heart rate, and Heather index were assessed at rest and during speech and cold pressor tasks in young adults. Participants (n = 152) were classified as myocardial, vascular, or mixed-mild responders based on CO and TPR responses to speech presentation. Vascular responders exhibited slower CO and TPR speech recovery than the myocardial and/or mixed-mild groups. Responder type differences in reactivity showed limited task-generalizability. The sustained vascular response pattern of the vascular group is consistent with that seen in hypertension. In light of associations of heightened TPR with markers of disease risk, this suggests potentially negative health implications for vascular responders.     

Cardiovascular reactivity, Type A behavior, and coronary heart disease: Comparisons between myocardial infarction patients and controls during laboratory-induced stress

Cardiovascular responses to a series of laboratory stressors were examined in middle-aged Type A and Type B men. The subjects were 30 patients with diagnosed myocardial infarction (NYHA Class 1) and 26 age-matched healthy controls. All subjects were nonsmokers in the normotensive range, and none were on medication. Blood pressure, heart rate, forearm blood flow and resistance, and impedance cardiography-determined response variables were obtained during performance and recovery periods of both mental and physical tasks. The patients showed elevated reactivity in systolic blood pressure and cardiac output and prolonged systolic lime ratio during mental stress tasks and elevated total peripheral resistance and lower cardiac output and stroke volume during physical tasks, as compared with control subjects. Thus, the difference in blood pressure reactivity between patients and controls appeared to be primarily dependent on the vascular component during physical tasks, whereas the mental tasks promoted a hemodynamic response pattern more consistent with beta adrenergic activation. Type A men, irrespective of coronary status, showed larger systolic and diastolic blood pressure response to both mental and physical stress than did Type B men.     

Serum Lipids,Neuroendocrine, and Cardiovascular Responses to Stress in Men and Women with Mild Hypertension

Abstract

In this study, we examined the relation between serum lipid levels, gender, and cardiovascular and neuroendocrine stress reactivity in patients with mild hypertension. Ninety-nine individuals (62 men, 37 women) with mild hypertension performed four mental stress tasks: mental arithmetic, public speaking, cold stress, and a computer videogame. Cardiovascular reactivity scores were computed by subtracting the minimum resting blood pressure (BP) and heart rate (HR) values from the maximum values obtained during each task. Neuroendocrine reactivity was calculated as the change from epinephrine and norepinephrine values from mean rest to mean task. High and low reactors were identified on the basis of median splits of reactivity scores, averaged across all four stressors. High systolic blood pressure reactors had higher levels of total (TC), low-density lipoprotein cholesterol (LDL-C), and apo-B than did low reactors. High diastolic blood pressure reactors had lower levels of high-density lipoprotein cholesterol (HDL-C) and higher levels of LDL-C and apo-B than did low reactors. High HR reactors had higher apo-AI:apo-AII ratios than low reactors. Lipid levels were not different for high and low epinephrine and norepinephrine reactors. Although women were noted to have more favorable lipid profiles than men, both male and female hypertensive patients who were high reactors had less favorable lipid profiles than low reactors.     

The relationships of impulsivity and cardiovascular responses: The role of gender and task type

The present study was conducted to assess the relationships of impulsivity with both baseline cardiovascular levels and reactivity during two laboratory stressors in both female and male young adults. Heart rate (HR), blood pressure (BP), and heart rate variability (HRV) were measured at rest and during a reaction time and speech task in one hundred and one undergraduate students. Impulsivity was measured using the Barratt Impulsiveness Scale-11 and Block's Ego-Undercontrol Scale. Males and females responded similarly to both laboratory tasks and also did not differ on the impulsivity scales. For males, higher scores on impulsivity were associated with higher systolic BP levels at rest but decreased systolic BP and HR reactivity during the preparation of the speech task; females showed no relationships of resting cardiovascular levels with impulsivity, but more impulsive females did show decreased HR response during speech preparation. No significant relationships were found between impulsivity and either HRV levels or reactivity. It is speculated that tasks involving a degree of planning may be important to find relationships between impulsivity and cardiovascular reactivity, especially in males.     

Anhedonia and effort mobilization in dysphoria: Reduced cardiovascular response to reward and punishment

Instigated by evidence for reduced responsiveness to reward in depression, the present two studies addressed the question if such anhedonic behavior would also become evident in reduced mobilization of mental effort in terms of cardiovascular reactivity. Undergraduates completed the Center for Epidemiologic Studies-Depression Scale (CES-D) and worked on mental tasks, expecting either no consequence, a performance-contingent reward, or a performance-contingent punishment. Study 1 revealed that participants with low CES-D scores showed high systolic blood pressure reactivity in the punishment condition, whereas participants with high CES-D scores showed low systolic reactivity. Study 2 corroborated this finding for reward: Nondysphoric participants expecting a reward showed higher reactivity of systolic blood pressure and pre-ejection period than participants in the neutral condition or than dysphoric participants. Together, the studies demonstrate that reward insensitivity in (subclinical) depression is also found in cardiovascular reactivity. Furthermore, dysphoric individuals do not respond to punishment either, suggesting a general insensitivity to hedonic consequences.     

Classification of individual differences in cardiovascular responsivity: The contribution of reactor type controlling for race and gender

Classification of 150 normotensive or mildly hypertensive men and women into myocardial, vascular, or mild reactors was accomplished using a regression-based approach. The method was based on the participants’ cardiac output (CO) and total peripheral resistance (TPR) reactivity to the speech presentation task. This task purportedly can elicit both myocardial and vascular responses. Cut-scores were based on the v-intercept from the linear regression of the CO reactivitv on TPR reactivity and vice versa. A greater percentage of Black men were classified as vascular responders as compared to Black women and White participants. Groups were found to differ on cardiovascular reactivity to the speech preparation, cold pressor, and mirror tracing tasks in predictable ways, after controlling for gender and ethnicity. Groups were also differentiated by ambulatory blood pressure and hypertensive status. The study supports the classification of homogeneous groups of participants based on the relative extent to which myocardial or vascular mechanisms dominate the reactivity to stress.     

Association Between Hemodynamic Profile During Laboratory Stress and Ambulatory Pulse Pressure

Hemodynamic responses underlying blood pressure reactivity to laboratory stress are theoretically linked to cardiovascular pathophysiology. The present study investigated whether a vascular response predicted ambulatory pulse pressure, a known risk factor for cardiovascular disease. A new model of hemodynamic profile, previously developed by the authors, was applied to 24-h ambulatory data from 30 female and 34 male healthy young adults. Of these, 40 were monitored during a naturalistic stressor (university examination). For females, hemodynamic profile significantly predicted nighttime systolic blood pressure, and 24-h, day-, and nighttime diastolic blood pressure, but not ambulatory pulse pressure. A vascular or mixed hemodynamic profile significantly predicted 24-h and daytime ambulatory pulse pressure in males. The findings are consistent with theories of pathogenic mechanisms involving vascular changes and suggest that, for males, a vascular or mixed hemodynamic profile measured during laboratory stress may be a risk marker for cardiovascular disease, by its association with ambulatory pulse pressure.     

Cardiovascular reactivity of Singaporean male police officers as a function of task, ethnicity and hostility.

OBJECTIVE: This research examined hemodynamic processes in cardiovascular reactivity (CVR) as a function of task, ethnicity and trait hostility. METHOD: One hundred and fourteen male patrol officers from the Singapore Police Force participated in this experimental study. Trait hostility was measured using the interpersonal hostility assessment technique to derive a hostile behavior index (HBI). Heart rate, blood pressure and hemodynamic measures were taken while participants performed three tasks: mental arithmetic, number reading and anger recall (AR). RESULTS: AR elicited the greatest blood pressure, vascular and cardiac output reactivity. HBI scores were positively related to systolic blood pressure reactivity during AR for Malays whereas this was not true for Indians and Chinese. Across tasks Indians with high HBI scores appeared to be cardiac reactors whereas the reactivity patterns for Malays and Chinese were undifferentiated. Self-report of negative mood was not related to CVR. CONCLUSION: These results are consistent with the higher rates of coronary heart disease deaths among Indians as well as the higher rates for hypertension among Malays in Singapore.     

Motor preparation aspects of cardiovascular reactivity to psychological challenge

Neural control of the circulation has evolved in such a way that behavioral responses to psychological stress may be accompanied by a dramatic activation of the cardiovascular system. This study was designed to address the hypothesis that such instances of cardiovascular mobilization reflect a functional motor preparation response. Twenty-four healthy young men participated in reaction time (RT) tasks which involved responding by squeezing a handgrip dynamometer. Motor preparation demands were manipulated by varying the temporal predictability of response requirements as well as the physical effort involved in responding, while controlling for other factors previously established to influence cardiovascular reactivity to psychologically challenging tasks. Physiological response measurements included heart rate, blood pressure and oxygen consumption. Increases in heart rate and systolic blood pressure during the RT tasks showed a general pattern which was consistent with the predictions of the motor preparation hypothesis, with the greatest elevations occurring in association with low temporal predictability and high physical effort. The possibility is discussed that factors such as incentives and elements of uncertainty may influence cardiovascular reactivity by accentuating behavioral arousal, of which motor preparation may be an inextricable component.     

Family History of Hypertension and Cardiovascular Changes During High and Low Affect Provocation

The present study investigated whether subjects with a positive family history of hypertension would display differential responses in blood pressure and heart rate across different laboratory tasks. We also wanted to know whether subjects would display stable within-subject responses across different laboratory tasks. Twenty-three family history positive subjects and 23 with a negative family history participated in three tasks: 1) mental arithmetic, 2) a conversation about the weather (low affect task), and 3) a conversation about a recent upsetting, interpersonal event (high affect task). Positive family history was associated with elevated diastolic resting blood pressure and greater diastolic responsivity overall. For both groups, arithmetic was associated with the greatest heart rate changes, whereas the distressing conversation was accompanied by the greatest diastolic blood pressure response. Stability of cardiovascular activation across different tasks was present only for heart rate; it was weak for diastolic blood pressure, and completely absent for systolic blood pressure.     

Cardiovascular and Electrodermal Response Patterns in Heart Rate Reactive Individuals During Psychological Stress

The goal of this research was to examine the cardiovascular and electrodermal response patterns of heart rate reactive and nonreactive individuals to psychological stress. Sixty males were tested while resting, listening to tones, identifying tone patterns, and performing mental arithmetic. Dependent variables were blood pressure, heart rate (HR), and skin conductance responses. Based on the change in HR from baseline to the first minute of mental arithmetic, two extreme reactivity groups of 15 subjects each were formed. Results indicated that HR reactive subjects had higher systolic blood pressure and HR than nonreactives. Reactives showed greater HR lability during all the tasks and a phasic acceleration to tones, while nonreactives showed a deceleration. Finally, comparisons of skin conductance responses indicated that subjects who were nonreactive when measuring HR were more reactive when measuring skin conductance. The HR reactivity seen in these subjects has been linked to predisposition to psychosomatic illness, and the current findings are discussed in that light.     

Comparison of cardiac versus vascular reactors and ethnic groups in plasma epinephrine and norepinephrine responses to stress

This study examined differences in plasma epinephrine (EPI) and norepinephrine (NOREPI) responses to stressors in 67 healthy African-American and Caucasian American men and women of the ages 18 to 49. Subjects were divided into three groups: (a) those who showed high blood pressure (BPI responses to stress associated with consistently high cardiac output (CO) increases with no substantial increases in total peripheral resistance (TPR), labeled cardiac reactors: (b) those with equally high BP increases associated with consistently higher TPR increases and lesser CO increases. labeled vascular reactors; (c) those who showed mixed hemodynamic responses or were low BP reactors. Ethnic and gender group differences in EPI and NOREPI responses were also examined. Cardiac reactors, vascular reactors and mixed + low reactors did not differ in EPI or NOREPI levels at baseline. During stressors, cardiac reactors showed greater increases in plasma EPI than vascular reactors or others during math, reaction time, and passive and active speech tasks: they also showed a weak trend toward greater NOREPI increases during these challenges as well. No differences were seen during the cold pressor: this stressor evoked the least change in EPI of all tasks, whereas the active speech elicited the greatest increases in both EPI and NOREPI of all tasks. Vascular reactors did not differ from mixed + low reactors in EPI or NOREPI reactivity, and men and women did not differ in EPI or NOREPI reactivity to any task. In contrast, Black subjects showed greater increases in NOREPI levels across all stressors compared to White subjects. These findings have implications for investigations of the role of sympathetic nervous system activity in the pathogenesis of hypertension in both African-American and Caucasian American populations.     

Frontal electrocortical and cardiovascular reactivity during happiness and anger

The present study investigated electrocortical and cardiovascular reactivity during positive and negative emotion, and examined the relation of asymmetric frontal lobe activation to cardiovascular responses. Participants were 30 healthy, right-handed university students (mean age, 23.9; 60% female; 76% Caucasian). Electroencephalographic (EEG), blood pressure (BP), and heart rate (HR) responses were assessed while subjects engaged in laboratory tasks (personally-relevant recall tasks and film clips) designed to elicit happiness or anger. Happiness-inducing tasks evoked more prominent left than right frontal EEG activation, and greater left frontal EEG activation than anger-inducing tasks. However, anger-inducing tasks were, on average, associated with comparable left and right frontal EEG activation. Irrespective of emotional valence, cardiovascular activation was more pronounced during personally-relevant recall tasks than during the viewing of film clips. During anger recall, both greater left frontal EEG response (r=-0.46, P<0.02) and greater right frontal EEG response (r=-0.45, P<0.02) were correlated significantly with increased HR reactivity during the task. In addition, a right lateralized frontal EEG response during anger-inducing tasks was associated with greater concomitant systolic BP (P<0.03) and diastolic BP (P<0.008) reactivity. Exploratory analyses also indicated that men who displayed a left lateralized frontal EEG response during happiness-inducing tasks showed the greatest concomitant systolic BP and HR reactivity (P's<0.03). These findings suggest that asymmetric frontal EEG responses to emotional arousal may elicit different patterns of cardiovascular reactivity in healthy adults.     

Children''s Cardiovascular Reactivity: Stability of Racial Differences and Relation to Subsequent Blood Pressure over a One-Year Period

After measuring blood pressure and heart rate at rest and during a video game procedure in 477 children enrolled in 3rd grade, 434 (91%) children had these measurements repeated a year later in 4th grade. Black children demonstrated greater blood pressure and heart rate reactivity than White children in both years, and an increase in heart rate reactivity from 3rd to 4th grade. Gender effects were inconsistent. Systolic and diastolic blood pressures during the video game were more highly correlated from year-to-year than were the resting measures. Regression analysis indicated that systolic reactivity was significantly related to subsequent systolic pressure at rest, particularly among Black girls. Diastolic reactivity was associated with subsequent resting diastolic pressure only among White children. Associations between reactivity and future blood pressure were independent of initial resting blood pressure. This study suggests that cardiovascular reactivity to psychological stress may be one important factor in future level of blood pressure and that the increased heart rate reactivity of Black children may be associated with the prevalence of hypertension among Black adults.     

1-Year stability and prediction of cardiovascular functioning at rest and during laboratory stressors in youth with family histories of essential hypertension

Blood pressure (BP). heart rate, cardiac index, and total peripheral resistance index were measured at rest and in response to postural change, forehead cold stimulation, and a video game challenge in a sample of 128 White and 155 African-American normotensive youth with family histories of essential hypertension (EH). These measurements were readministered 1 year later (12.5 +/- 3.2 months). Moderate temporal stability was observed for all resting and absolute stress responses. Reliability estimates for reactivity change scores were lower, although some were within acceptable ranges. African-American youth exhibited greater BP and peripheral resistance index reactivity to forehead cold on both evaluations. After controlling for various anthropometric and demographic parameters and the pertinent previous year's resting cardiovascular (CV) parameter, mean video game systolic blood pressure (SBP) responses were predictive of resting SBP whereas absolute forehead cold and video game diastolic responses predicted resting diastolic blood pressure (DBP) 1 year later. Mean video game DBP responses were also predictive of resting peripheral resistance index after controlling for significant demographic and anthropometric measures. CV reactivity is discussed with regard to possible value in prediction of changes in resting BP and cardiac structure prior lo establishment of EH.     

Behaviorally-evoked plasma catecholamine response and 24-hour excretion of urinary catecholamines among cardiac and vascular reactors

Individuals differ in the cardiac and vascular processes that underlie blood pressure elevations evoked by environmental stimuli; such differences may reflect variability in sympathoadrenal response. We separated 108 healthy, young-adult males into those with predominant elevations in either cardiac output or peripheral resistance when exposed to psychological challenges. We then asked if they differed on other measures of cardiovascular response, concomitant plasma catecholamine reactions or 24-h urinary excretion of catecholamines. Cardiac reactors, relative to vascular reactors, showed reduced cardiac pre-ejection period, a smaller reduction in stroke volume, and elevated plasma epinephrine response and 24-h urinary epinephrine excretion. Vascular reactors, relative to cardiac reactors, responded to mental stress with more elevated diastolic blood pressure, a rise in peripheral resistance and pulse wave velocity, and a greater reduction in stroke volume. Vascular reactors, however, did not show plasma norepinephrine response or 24-h urinary norepinephrine excretion that was greater than cardiac reactors. The results provide partial support for the hypothesis that variability in sympathoadrenal activity contributes to individual differences in cardiac and vascular reactivity, and extend prior observations by demonstrating covariation of behaviorally-elicited cardiac reactivity with the 24-h excretion of epinephrine.