Partner interactions are associated with reduced blood pressure in the natural environment: ambulatory monitoring evidence from a healthy, multiethnic adult sample.

OBJECTIVE: The objective of this study was to examine the effects of partner interactions on ambulatory blood pressure in a sample of 120 healthy adults who were monitored over a 6-day period. METHODS: After each blood pressure measurement, participants rated characteristics of ongoing social interactions, along with emotional activation, physical activity, talking, posture, and other covariates, with computer-assisted self-report assessments. RESULTS: Using multilevel modeling, we showed that blood pressure was significantly lower during social interactions with one's partner relative to social interactions with any other person and relative to periods of not interacting. Interactions with partners also were characterized by significantly less talking and emotional activation and more intimacy and perceived emotional support; however, these differences did not mediate the partner effect on blood pressure. In addition, the relative benefits of interacting with a partner were not moderated by relationship quality, gender, or race. CONCLUSIONS: The effects of social situations on ambulatory blood pressure may represent one pathway through which social relationships affect cardiovascular health. Key words: blood pressure, social interaction, partner interactions, cardiovascular health.

Anticipatory blood pressure responses to exercise are associated with left ventricular mass in Finnish men: Kuopio Ischemic Heart Disease Risk Factor Study.

BACKGROUND: Exaggerated cardiovascular reactivity to psychological demands may contribute to the development of left ventricular (LV) hypertrophy. We examined the cross-sectional association between anticipatory blood pressure (BP) responses to bicycle exercise and LV mass in the Kuopio Ischemic Heart Disease Risk Factor Study, a population-based epidemiological sample. METHODS AND RESULTS: Among 876 men from 4 age cohorts (ages 42, 48, 58, and 64 years), we collected echocardiographic assessments of LV mass along with measures of BP response taken before bicycle ergometry testing. Anticipatory BP responses were positively associated with LV mass, with significant associations only among younger (age <50 years) subjects with elevated resting pressures (3-way interactions for anticipatory BP x age x resting pressure for systolic and diastolic BP, all P:<0.05; for younger subjects with elevated systolic BP, P:<0. 01; and for younger subjects with elevated diastolic BP, P:<0.001). Among these subgroups, exaggerated anticipatory BP responses (top quartile) were associated with an incremental increase in LV mass of 10% or greater, corrected for body surface area. Results remained significant after adjusting for age, education, salt consumption, and resting BP, and the pattern of findings was maintained among men with no previous history of cardiovascular disease. CONCLUSIONS: The tendency to show exaggerated pressor responses to psychological demands may be a significant independent correlate of LV mass, especially among young men with high resting pressures. This is the first study to examine such associations in a middle-aged population sample.

Enhancing the laboratory-to-life generalizability of cardiovascular reactivity using multiple occasions of measurement.

Studies examining the association between laboratory measures of stress-related cardiovascular (CV) reactivity and responses to psychological challenges in the natural environment have yielded mixed results. Frequently, single laboratory tasks have been used to predict responses to natural stressors on a single occasion of measurement. Because aggregation broadens the range of stimuli sampled and reduces measurement error, laboratory-to-life generalizability should be more easily detected when multiple predictor and criterion observations are used. Sixty students in a public speaking course were administered multitask assessments of CV reactivity during two laboratory sessions and during two in-class public speech assignments. CV responses to the classroom speeches were greater among those who showed larger responses in the laboratory, and these associations became stronger as measures were aggregated across multiple samples of behavior. These results support the generalizability of CV reactivity as a measure of individual difference, and they help to shed light on previous inconsistent findings in this area.

Psychosocial mediators of racial differences in nighttime blood pressure dipping among normotensive adults.

Shallow declines in nocturnal compared with diurnal blood pressure (BP dipping) have been associated with cardiovascular disease. In U.S. samples, Blacks demonstrate less BP dipping compared with Whites. In a sample of 60 Black and 60 White normotensive adults we examined stress, social integration (including parental status), social support, and hostility as potential mediators of the association between race and BP dipping. The effect of race on diastolic BP dipping was partially mediated by parental status. The effect of race on heart rate dipping was partially mediated by stressful life events. No psychosocial factors mediated the relation between race and systolic BP dipping. Although psychosocial factors appear to account for some of the observed racial differences in nocturnal blood pressure decline, our data suggest that these differences cannot be attributed entirely to covarying psychosocial effects.

Negative emotions and acute physiological responses to stress.

One pathway through which stressors are thought to influence physiology is through their effects on emotion. We used meta-analytic statistical techniques with data from nine studies to test the effects of acute laboratory stressors (speech, star mirror-image tracing, handgrip) on emotional (undifferentiated negative emotion, anger, anxiety) and cardiovascular (CV) response. In all of the studies, participants responded to stressors with both increased CV response and increased negative emotion. Increases in negative emotion were associated with increases in CV response across tasks, however, these associations were small. The range of variance accounted for was between 2% and 12%. Thus, the contribution of negative emotion, as assessed in these studies, to physiological responses to acute laboratory stressors was limited. Although these results raise questions about the role of emotion in mediating stress-elicited physiological responses, the nature of the acute laboratory stress paradigm may contribute to the lack of a strong association.

Effects of task strain, social conflict, and emotional activation on ambulatory cardiovascular activity: daily life consequences of recurring stress in a multiethnic adult sample.

Ambulatory blood pressure (ABP) may be an independent predictor of cardiovascular endpoints, but little is known about its psychosocial determinants. The acute effects of psychosocial processes on cardiovascular activity during daily life were examined by random-effects regression. Healthy adults (N = 120) were monitored over a 6-day period with ABP monitors and computer-assisted self-report assessments. Task strain, social conflict, and emotional activation were rated following each ABP measurement, as were activity, posture, and other covariates. Results show that blood pressure (BP) and heart rate (HR) were elevated during periods of emotional activation (high negative affect or high arousal). Diastolic BP was lower during periods involving high decisional control, and HR was lower during high-control, low-demand activities. There were substantial individual differences in the effects of psychosocial influences on ambulatory cardiovascular activity. Psychological factors are reliable determinants of ABP, which may account in part for the unique predictive value of ABP.

The effects of the social environment on stress-related cardiovascular activation: current findings, prospects, and implications.

Social relationships have been shown to be health-protective and to improve cardiovascular disease prognosis. One of the mechanisms by which social relationships may alter health status is through altering patterns of neuroendocrine or hemodynamic responding to ongoing activity. For example, research with non-human primates suggests that disrupted social relationships may increase cardiovascular risk through their effects on sympathetic nervous system activation. In humans, a number of recent reports have shown that the presence of an affiliative companion can reduce cardiovascular activity during psychologically challenging tasks, results which are consistent with this proposed mechanism of effect. We review the recent human literature which has examined the effects of the social environment on stress-related cardiovascular activity. Although findings in this literature are generally consistent, recent anomalous results are reviewed which shed light on some of the context-dependent effects of social affiliation. Additional areas for further investigation are examined, including possible mechanisms for explaining these social affiliation effects, individual differences which may moderate these effects, and emerging methodological advances for examining how these effects may generalize to the natural environment.

Exaggerated blood pressure responses during mental stress are associated with enhanced carotid atherosclerosis in middle-aged Finnish men: findings from the Kuopio Ischemic Heart Disease Study.

BACKGROUND: Exaggerated cardiovascular reactivity to mental stress is hypothesized to increase atherosclerotic risk. We examined this hypothesis using cross-sectional data from the Kuopio Ischemic Heart Disease study, a population-based epidemiological sample. METHODS AND RESULTS: 901 Eastern Finnish men from four age cohorts (age, 42 to 60 years) were administered a standardized testing battery to assess cardiovascular reactivity to mental stress. Ultrasound measures of intima-medial thickness (IMT) and plaque height from the common carotid arteries were used as noninvasive markers of atherosclerosis. Diastolic blood pressure (DBP) responses to mental stress were significantly associated with mean IMT (b=.021, P=.006), maximum IMT (b=.026, P=.013), and mean plaque height (b=.017, P=.041). Significant associations were also shown between stress-related systolic blood pressure (SBP) reactivity and mean IMT (b=.0151, P=.042). When examined separately by age, associations with IMT were significant only in the youngest half of the sample (age, 46 and 52 years, n=433; for mean IMT, DBP b=.033, P=.0002, SBP b=.0266, P=.003; for maximum IMT, DBP b=.039, P=.002, SBP b=.032, P=.011). Results remained significant in the younger subjects after adjustment for smoking, lipid profiles, fasting glucose, and resting blood pressure (b=.024, P=.011); results also remained significant in a subgroup of unmedicated younger subjects without symptomatic cardiovascular disease (n=135; for SBP reactivity, b=.031, P=.036; for DBP, b=.037, P=.007). CONCLUSIONS: The tendency to show exaggerated pressor responses to mental stress is a significant independent correlate of atherosclerosis in this population sample of Finnish men. The effect does not appear to be accounted for by the confounding influence of other risk factors or preexisting clinical disease.

Affiliation moderates the effects of social threat on stress-related cardiovascular responses: boundary conditions for a laboratory model of social support.

The authors tested the hypothesis that the response-attenuating effects of affiliation under stress are limited to conditions that involve high social threat. Ninety-six young adult women were exposed to standardized psychological challenges in one of four conditions that involved two levels of social affiliation (alone or accompanied by a close friend) and two levels of social threat (variations in the social behavior and perceived status of the experimenter). Social affiliation was associated with attenuated blood pressure responses to the challenges but only under conditions of high social threat. Affiliation was not associated with differences in self-reported emotional response to the challenges nor with alterations in cognitive task appraisal. Exploratory analyses suggested that some of these effects were stronger in hostile or socially avoidant individuals. Implications of these findings for interpreting the literature on social support and cardiovascular reactivity, and for understanding the potential role of social support in reducing stress-related disease pathogenesis, are discussed.

A multidimensional measurement model for cardiovascular reactivity: stability and cross-validation in two adult samples.

The factor structure for measures of stress-related cardiovascular reactivity was examined in 2 samples: a university campus employee sample (N = 72) and a sample of young adult twins (N = 113). In both samples, 5 noninvasive cardiovascular measures were monitored during a series of challenging laboratory tasks. We developed a 2-factor model depicting vascular and cardiac influences on responding. With confirmatory factor analysis, this model was shown to be consistent with the data across both samples, across 2 testing sessions, and across 2 sets of tasks. Latent variables measuring cardiac and vascular reactivity were highly reliable on retest as well. Individual differences in cardiovascular reactivity to mental stress may be characterized by a stable, 2-dimensional pattern of response.

Reliable responses to a cardiovascular reactivity protocol: a replication study in a biracial female sample.

This replication study was designed to examine the reliability of individual differences in cardiovascular responsivity to a standardized PC-based cognitive task protocol (Kamarck et al., 1992) in a female community sample. Thirty women, both black and white (ages 25-44 years), were administered the protocol twice with a 1-month retest interval using a mobile laboratory at a community-based testing site. Measures of heart rate and blood pressure reactivity were obtained comparing assessments taken at rest and during three protocol tasks. Preejection period, stroke volume, and total peripheral resistance changes were estimated using impedance cardiography assessments. As in previous studies with males, individual differences in heart rate and systolic and diastolic blood pressure responses to the protocol were highly reliable (.80 or greater) when data were aggregated across three tasks and two testing sessions. Reliability of cardiac contractility (preejection period) and stroke volume changes to these tasks exceeded .70. This reactivity assessment procedure has now produced reliable results in three studies and appears to be exportable across diverse samples and settings.

Stability of cardiac impedance measures: aortic opening (B-point) detection and scoring.

The accurate assessment of cardiac stroke volume measured by impedance cardiography depends on the reliable measurement of dZ/dtmax and the accurate detection of the relevant points on the impedance cardiogram. In one study, impedance cardiograms were collected for 75 subjects during resting conditions and during four psychologically challenging tasks, in two identical testing sessions. The reliability of stroke volumes calculated from dZ/dtmax measured from the electrical baseline and from the dZ/dt B-point on the waveforms were assessed for the two testing sessions. Consistently higher (but not statistically different) test-retest correlations were observed for the measures calculated using values of dZ/dtmax measured from the B-point. In a second study, dZ/dt waveforms with no B-point reversal from 21 subjects were scored using two alternative B-point detection algorithms: the reversal of the second derivative of delta Z and the peak of the third derivative of delta Z. Both algorithms demonstrated high reliability compared with an expert human operator. The reversal on the second derivative may better locate an inflection point on the dZ/dt signal and the third derivative may provide a good B-point estimation in the absence of any inflection point.

Recent developments in the study of cardiovascular reactivity: contributions from psychometric theory and social psychology.

Two related ongoing research programs are described. The first examines optimal measurement strategies for assessing individual differences in cardiovascular reactivity, and the second investigates the effects of the social environment as a moderator of cardiovascular responding during psychological challenge. Models and evidence from related behavioral sciences (Psychometric Theory and Social Psychology, respectively) have provided useful guidance for this work. Relevant background and current data examining the measurement and determinants of cardiovascular reactivity are reviewed, with a focus on these multidisciplinary contributions. The implications of the work for the construct of reactivity and its possible role as a marker of disease risk are discussed.

Reliable measures of behaviorally-evoked cardiovascular reactivity from a PC-based test battery: results from student and community samples.

This paper describes efforts to reduce measurement error in the assessment of cardiovascular reactivity by standardizing task requirements and by aggregating data across tasks and testing sessions. Using these methods, reliable measures of reactivity (.80 or greater) were obtained on five different measures of cardiovascular function (heart rate, systolic blood pressure, diastolic blood pressure, stroke volume, pre-ejection period) in samples of college students and community volunteers. Methodological limitations may have hampered previous efforts in this area. Current findings are consistent with a dispositional model of cardiovascular reactivity, and they suggest productive future strategies for obtaining reliable assessments.

A computerized test battery for the assessment of cardiovascular reactivity.

Recent evidence has suggested a possible relationship between the tendency to exhibit excessive cardiovascular reactions during psychological challenge and the risk of cardiovascular disease. Valid techniques for reliably assessing such reactions are, however, minimally available. A test battery for the assessment of cardiovascular reactivity to experimental challenge is currently being developed at the University of Pittsburgh in conjunction with the University of Miami and Duke University. An IBM-AT compatible microcomputer is being used for the concurrent collection of physiological data and presentation of the laboratory stressors. Digitized cardiovascular data being collected include EKG, Impedance Cardiogram (ICG), phonocardiogram, and a peripheral pulse wave measure. Blood pressure readings are also being collected and stored on disk. The computer presents three challenging video games, each designed to elicit cardiovascular reactions. Processing programs are being used and developed for the standardized scoring of the digitized signals. To assist in epidemiological research a mobile testing unit has been assembled for the easy administration of the test battery in varying geographical locations. The test battery being developed will increase the feasibility of epidemiological and clinical assessment of stress-induced cardiovascular responses which may substantiate a link between reactivity and cardiovascular disease.

Social support reduces cardiovascular reactivity to psychological challenge: a laboratory model.

In this study we investigated the effects of nonevaluative social interaction on the cardiovascular response to psychological challenge. Thirty-nine college-age females appeared accompanied ("Friend" condition) or unaccompanied ("Alone" condition) to an experimental laboratory. In the Friend condition, partners were present while the subject participated in two laboratory tasks, and the partners' evaluation potential was minimized by design. Subjects in the Friend condition showed reduced heart rate reactivity to both tasks, relative to the Alone group, an attenuated task-related systolic blood pressure response to one of the tasks, and a reduced diastolic blood pressure increase during a solitary interview. In two other instances, partner-related response reductions were apparent only for Type A subjects. None of these effects was accompanied by differences in task performance or self-reported emotional response. Interpersonal support may reduce cardiovascular responsivity to stress, an effect with possible implications for understanding the association between social relationships and cardiovascular risk.

Program adherence and coping strategies as predictors of success in a smoking treatment program.

Ninety-four participants in a 6-week behaviorally oriented smoking cessation program were administered weekly questionnaires assessing their use of the major program recommendations and other quitting strategies throughout treatment. An "affect-regulation" coping inventory was administered at the beginning and end of treatment as well. Adequate adherence was reported for most of the program recommendations. Although a composite measure of adherence did not predict quitting success, adherence and coping assessments were associated with maintenance of treatment gains. Short-term maintenance was associated with an extensive affect-regulation repertoire and use of "stimulus control" strategies during the program, and long-term maintenance was associated with consistent self-monitoring of smoking during treatment. These prospective findings highlight some behavioral characteristics that may be useful targets in future efforts to foster maintenance of smoking behavior change.