Psychological variables in hypertension: relationship to casual or ambulatory blood pressure in men.

OBJECTIVE: The evidence linking hypertension with personality or psychological characteristics, such as anger, anxiety, or depression, remains equivocal. This may be due in part to limitations of personality theory, confounding by awareness of hypertension, and/or inherent difficulties in measuring blood pressure. This study was designed to investigate the association between mild hypertension as defined by both ambulatory and casual (clinic) blood pressure measurements and various measures of personality and psychological characteristics. METHODS: We examined this association in a population-based sample of 283 men between the ages of 30 and 60 years from eight work sites in New York City, using an ambulatory blood pressure monitor and controlling for age, race/ethnicity, and body mass index. RESULTS: We found no consistent difference between participants with mild hypertension and those with normal blood pressure on any of the psychological variables assessed, including Type A behavior pattern, state and trait anger, anger expression, anxiety, symptoms of psychological distress, locus of control, or attributional style. Results were not due to the use of antihypertensive medication by some of the participants with hypertension nor to the dichotomization of blood pressure into those with and without mild hypertension. This contrasts with previous findings from this study showing a sizable association of ambulatory blood pressure and hypertension with job strain (a situational measure), age, and body mass index. CONCLUSIONS: These null results suggest that situational, biological, and perhaps behavioral factors are the primary determinants of mild hypertension and that the predictive significance of psychological or dispositional factors is low or negligible in those without overt cardiovascular disease.

How should we measure blood pressure in the doctor's office?

BACKGROUND: Blood pressure is the most ubiquitous diagnostic recording made in the doctor's office, but the measurement is subject to a number of sources of bias, which may lead to over- or underestimation. The current study examined the systematic influence of the way in which the measurements were taken - by the physician, by a nurse, or with the patient sitting alone, using an automated device. SUBJECTS AND METHODS: Blood pressure was measured in 17 essential hypertensive and 10 white-coat hypertensive individuals. On separate clinic visits, measurements were taken by the attending physician, by a nurse and using an automated device (Arteriosonde 1216). RESULTS: A repeated-measures ANOVA revealed that, for systolic pressure, there was a significant effect of measurement modality on blood pressure. Physician systolic pressures were on average approximately 10 mmHg higher than those taken by a nurse, nurse pressures being approximately 7 mmHg higher than those recorded using Arteriosonde. The effect on diastolic pressure was similar but smaller, and no nurse-Arteriosonde difference was observed. CONCLUSIONS: We conclude that the routine clinical assessment of blood pressure would be more representative of daily ambulatory pressure if an automated device, without doctor or nurse present, were used.

On the reliable assessment of cardiovascular recovery: an application of curve-fitting techniques.

The underuse of cardiovascular recovery as an adjunct to reactivity may stem from a lack of research on how to assess the process reliably. We explore the test-retest reliability of three simple, intuitive approaches to measuring recovery, and of a more sophisticated curve-fitting technique. Eighteen young normotensive subjects experienced three stressors twice each, with 10-min baseline, 3-min task, and 20-min recovery periods and continuous monitoring of heart rate and blood pressure. Reactivity showed moderate reliability, but the three simple approaches to measuring recovery revealed essentially none. However, the curve-fitting approach, using a three-parameter (amount, speed, and level of recovery) logistic function was reliable. This approach, capturing the inherently dynamic process of cardiovascular recovery, may allow researchers to usefully add the assessment of recovery to paradigms exploring reactivity as a risk factor for cardiovascular disease.

Social support and cardiovascular reactivity.

Recent experimental work on the benefits of social support in buffering cardiovascular stress responses builds on prior epidemiological, psychological, and physiological work. Epidemiological data show that social integration is associated with better health, but cannot unambiguously establish causality (it could be that healthy people attract more friends), nor that the mechanism is psychological (the mechanism could be behavioral; for example, with friends encouraging exercise). Social psychological work suggests that people prefer to be with others, especially in times of stress, and that they evaluate themselves, and their emotional responses, by observing the people around them. This work, while establishing a desire for affiliation, does not show that being with others translates into health benefits. Physiological evidence suggests that exaggerated cardiovascular responses to stress are associated with the development of hypertension and cardiovascular disease, but does not indicate how such potentially damaging stress responses can be reduced. Experimental work on social support and cardiovascular reactivity overcomes many of these limitations. The presence of an ally, especially a female, markedly reduces cardiovascular responses compared both to the presence of an non-supportive other, and to experiencing the stress alone. One fruitful area for further work is the role of social support following stress, both in speeding the cardiovascular return to pre-stress levels, and in limiting rumination-induced cardiovascular responses.

An historical context for behavioral models of hypertension.

OBJECTIVE: The purpose of this study is provide an historical context for current behavioral models of hypertension. METHODS: A selective sample of the cardiovascular reactivity literature was reviewed, from 1932 to present. RESULTS: In the earliest model, cardiovascular reactivity was regarded as a marker of disease risk; however, in later models, reactivity came to be viewed as a causal influence in the development of hypertension. As the models evolved, the underlying assumptions changed. Thus, the risk marker model assumed that cardiovascular responses to stress were a stable, generalized characteristic of the individual, and therefore the eliciting stimuli were arbitrary. The later models, however, assume that the nature of the eliciting stimulus is a determinant of the cardiovascular response. We describe the increasing complexity of the four models, and contrast their underlying assumptions and the implications of these assumptions. CONCLUSION: We provide an overview of study designs and variables that should be incorporated into studies seeking to understand the ways in which cardiovascular responses to stress may influence the development of hypertension.

Gender, social support, and cardiovascular responses to stress.

OBJECTIVE: Laboratory research indicates that the presence of a supportive other can reduce physiological responses to a stressor. Whether there are gender differences, either on the part of the provider or the recipient, in this social support effect is explored. Such differences might shed some light on the frequent epidemiological reports of gender differences in social support and health. METHODS: Male and female subjects gave an impromptu speech and received either standardized supportive or nonsupportive feedback from a male or female confederate. Blood pressure and heart rate were monitored continuously during baseline and speech periods. RESULTS: Speakers with a supportive female audience showed a systolic increase of 25 mm Hg over baseline. Those with a nonsupportive female audience increased 36 mm Hg. A supportive male audience led to increases of 32 mm Hg, and a nonsupportive male audience 28 mm Hg. There was no significant effect of gender of subject. CONCLUSIONS: Results indicate that social support provided by women reduced cardiovascular changes for both male and female speakers compared with presence of a nonsupportive female audience. Social support from men did not. These findings suggest a possible mechanism that might help explain the epidemiological literature on the relationship between gender, social support, and health. The findings are consistent with the notion that married men are healthier because they marry women. Women do not profit as much from marriage or suffer as much from separation, in terms of health outcomes, because the support they gain or lose is the less effective support of a man. These findings render more plausible the possibility that differences in social support might contribute to health differences, through the dampening of cardiovascular responses to stress.

Home blood pressure teletransmission for better diagnosis and treatment.

The rate of control of high blood pressure is disappointing, and noncompliance is one factor that contributes to this. The reasons for poor compliance are complex and include factors related to the patient, the healthcare provider, and the medical system. In general, the lack of regular communication between the patient and the physician, as occurs in the traditional model of clinic-based care, predicts a low rate of blood pressure control. In addition, clinic-based blood pressure rates are notoriously unreliable. A solution to this dilemma is teletransmission of self- measured blood pressure readings, which offers the dual advantages of more reliable measurements, and the establishment of regular telephone communication between the patient and the healthcare provider. Preliminary evidence with this type of system suggests that blood pressure control can be improved substantially.

The generalizability of cardiovascular responses across settings.

The generalizability of cardiovascular reactivity change scores remains largely unsupported. In previous studies, several factors differed between laboratory and field, making poor lab-to-life correlations difficult to interpret. The present study varied only one parameter between the lab and field: setting. In this study, 24 females were studied on four occasions: twice in the lab (to provide test-retest reliability); once in a classroom; and once at home. After a baseline, subjects performed a math task, while blood pressure and heart rate were monitored. Procedures were identical in all sessions. Blood pressure changes were fairly reliable between the two lab sessions, with rs values 0.68 (systolic) and 0.62 (diastolic pressure); however, lab/nonlab correlations were lower (0.47 for SBP; 0.38 for DBP). This suggests that even a minor variation in procedure, such as a change in setting, can affect generalizability; other lab-field differences may have an even greater impact.

The social construction of cardiovascular reactivity.

One can view the "reactivity hypothesis" as having two basic forms: the individual difference or personality approach, which suggests that people who show exaggerated cardiovascular responses to stress are at increased risk of developing cardiovascular disease, and the situational or social psychological approach, which suggests that circumstances which give rise to unusually large responses are those that put people at risk of disease. Both versions rely on the generality of cardiovascular responses across situations. Evidence is presented from two studies which indicate that such generality may, however, be hard to come by. In the first study, examining the personality approach, we show that a simple change in setting dramatically attenuates the consistency of reactivity. In the second study, from the social psychological perspective, we show that subtle alterations in the situation have profound effects on group mean responses. In both cases, reactivity proved extremely sensitive to the context, suggesting that testing in arbitrary and artificial settings cannot be expected to generalize well to the real world. Instead, we argue, careful attention to psychological naturalism is essential, with the testing carefully matched to specific real-world phenomena of interest.

Implications of alternative methods of computing blood pressure means.

BACKGROUND: Blood pressure measures are traditionally averaged to compute a level across a period. There are, however, two ways of calculating such means: by assigning equal weights to each time interval or to each heartbeat. The former method is used commonly with intermittent measures, the latter with continuous measurements, though either can be calculated with either monitoring technique. For periods during which there is substantial variability in the cardiovascular levels, and in which the pulse is correlated with the blood pressure, the two techniques will produce different results. METHODS: We illustrated the difference between the two techniques by calculating mean blood pressure levels during two episodes, with the heart rate and blood pressure monitored continuously using the Finapres 2300 blood pressure monitor. RESULTS: During the first episode, there was dramatic variability in heart rate and blood pressure. The pulse-based calculations, which give greater weight to the periods during which the pulse is elevated, gave means for the systolic and diastolic blood pressures substantially higher than those obtained using time-based methods. During the second episode, both the heart rate and the blood pressure were stable, and we observed no difference between the results from the two methods of calculating the means. CONCLUSIONS: Because there are theoretical justifications for both methods of computation, and they can produce different results, it is important that researchers attend to the difference, and describe the technique used when presenting results.

Social support effects on cardiovascular reactivity: is a stranger as effective as a friend?

OBJECTIVE: We investigated whether the effects on cardiovascular reactivity of social support from an audience member depend only on the behavior of that person or also depend on the relationship between the audience and the actor. That is, is there any added reduction in physiological response if the person who is nodding and smiling supportively is also a friend? METHOD: Ninety subjects gave a speech to an observer. In two of the conditions, this observer was a confederate of the experimenter and a stranger to the subject. This confederate acted in either a supportive or neutral manner during the speech. In the final condition, this observer was a friend, brought by the subject, who was then trained to show support in the same manner as the supportive confederate. The comparison of the two confederate conditions tested the effect of support, holding the relationship constant. The comparison of friend and confederate supportive conditions tested the effect of the relationship, holding the supportive behaviors constant. All participants were female. RESULTS: Both supportive conditions produced significantly smaller cardiovascular increases than the confederate-neutral condition, and the friend-supportive condition produced significantly smaller systolic blood pressure increases than the confederate-supportive (friend-supportive: 7.9 mm Hg: confederate-supportive: 14.9 mm Hg; confederate-neutral: 22.9 mm Hg). Differences for diastolic pressure and heart rate were not significant, although the data followed the same pattern. CONCLUSIONS: Social support from a friend attenuated cardiovascular reactivity in a laboratory setting to a greater degree than support from a stranger. The subjects' construal of the supportive behaviors can have an effect on reactivity, over and above the effects of the actual behaviors themselves.

Physiological stress reactivity and recovery: conceptual siblings separated at birth?

This article discusses theoretical assumptions underlying physiological stress reactivity research. It examines early conceptualizations of activation and recovery and contrasts these with current practices in designing, analyzing, and reporting stress reactivity studies. Study protocols from four major journals covering the last 2 years of publication were examined for current practices. Of the 105 studies which tested physiological reactivity, 63% collected recovery data but only 23% reported the recovery data. We concluded that stress recovery issues are neglected and a renewed case is made for their conceptual and ecological importance. The case for studying recovery is further supported by a selective review of studies using recovery protocols that revealed positive findings not apparent in reactivity comparisons only. Finally, options for sound design of recovery protocols, statistical processing of resulting data, and interpretation of findings are presented.

The application of generalizability theory to blood pressure resting levels and mental stress responses.

BACKGROUND: Blood pressure measurements taken in the clinic or laboratory are assumed to generalize to the world outside. This is true both of casual blood pressure measurements and of changes in blood pressure responses to stress. Such generalizability is crucial to the usefulness of blood pressure measurements as predictors of long-term disease. In previous generalizability studies, several factors differed between clinic/laboratory and field, making it difficult to interpret the poor laboratory-life associations. The present study varied only one parameter between the laboratory and the field setting. SUBJECTS AND METHODS: Twenty-four women were studied on four occasions: twice in the laboratory, once in a classroom, and once at home. After a resting baseline, the subjects performed a mathematics task, while blood pressure and heart rate were monitored. Only the setting was varied across sessions. RESULTS: Test-retest correlations were 0.81 for systolic blood pressure levels (SBP) and 0.61 for diastolic blood pressure levels (DBP). Generalizability (G) coefficients for blood pressure levels were approximately the same as the reliabilities ( 0.82, SBP; 0.59, DBP), indicating that the change in location did not affect resting levels. However, for change scores, the reliabilities were higher than the G coefficients. Test-retest correlations were moderate: 0.68 (SBP) and 0.62 (DBP). G coefficients were 0.47 (SBP) and 0.36 (DBP), indicating that the generalizability of change scores suffered due to the change in test location. CONCLUSION: A minor variation in procedure, such as a change in setting, has little effect on the generalizability of blood pressure resting levels, but a substantial effect on stress-response changes. Other laboratory-field differences may have an even greater impact on generalizability.

Environmental influences on blood pressure and the role of job strain.

OBJECTIVE: To review the evidence that human essential hypertension is at least in part the result of the influence of psychosocial factors, with special reference to occupational stress (job strain). FINDINGS: The prevalence of human hypertension is related to social factors such as urbanization and education. Several studies, conducted both experimentally in animals and observationally in people, have suggested that chronic social conflict is associated with higher blood pressure. Ambulatory monitoring has shown that most people have their highest pressures during working hours. Occupational stress can be evaluated as job strain, which is a combination of high demands at work with low decision latitude or control. Job strain has been related to coronary heart disease, and a number of studies have shown that it is also associated with higher ambulatory blood pressures, both cross-sectionally and prospectively, in men but not in women. Men in high strain jobs also show an increased left ventricular mass. Laboratory studies of blood pressure reactivity to stressful tasks support the concept of loss of control being associated with higher pressures. CONCLUSIONS: Job strain is a risk factor for hypertension in men, but not in women.

Self-efficacy as a component of active coping: effects on cardiovascular reactivity.

Active coping remains a poorly understood construct in cardiovascular reactivity testing. We have shown that active coping comprises two independent effects: the enhanced control and the effort of exercising control. The present study tested the proposition that, with effort left unconstrained, increased self-efficacy will increase cardiovascular response. Forty women were assigned to low or high self-efficacy conditions; self-efficacy was manipulated using false feedback. Subjects then engaged in a video game shape-matching task, while blood pressure and heart rate were monitored. SBP and DBP changes were smaller in the low self-efficacy group, as predicted: 17.9 versus 25.2 mmHG for SBP (p < 0.05); and 8.7 versus 13.0 mmHG for DBP (p = 0.07). Heart rate was similar for the two conditions. We conclude that self-efficacy for a task may be an integral part of the active coping process, indirectly affecting the blood pressure response by acting on the effort involved in the coping response.

Self-efficacy as a moderator of perceived control effects on cardiovascular reactivity: is enhanced control always beneficial?

We have found that enhanced control has an attenuating effect on cardiovascular reactivity when effort of responding is maintained constant; however, not all individuals will react to increased control in the same manner. In the present study, 40 subjects engaged in a mental arithmetic task under high control (self-paced) and low control (externally paced) conditions. Subjects' self-efficacy concerning this task was assessed. As expected, significant main effects were found for control condition, with high control producing smaller blood pressure and heart rate changes than low control (11.4 vs. 20.4 mm Hg (systolic blood pressure), 4.4 vs. 11.4 mm Hg (diastolic blood pressure), and 6.2 vs. 7.9 beats per minute (heart rate)). No main effects were found for self-efficacy. However, the interaction between control and self-efficacy was significant for systolic blood pressure and heart rate and marginally significant for diastolic blood pressure; post hoc tests showed that this was due to the effect of self-efficacy classification under high control conditions; subjects with low self-efficacy for the mental arithmetic task evidenced cardiovascular changes that were significantly greater than those of the high self-efficacy group (8.0 vs. 14.8 mm Hg (systolic blood pressure), 2.7 vs. 6.1 mm Hg (diastolic blood pressure), and 5.2 vs. 7.1 beats per minute (heart rate). The data suggest that the reactivity observed during active coping is due in part to the effort of responding and in part to the match between the demands of the task and certain mastery-related attributes of the individual.

Association between delayed recovery of blood pressure after acute mental stress and parental history of hypertension.

OBJECTIVE: To assess the influence of sex, race and parental history of hypertension on blood pressure and heart rate elevations during a stressor, and on the recovery of prestress baseline levels for these parameters. DESIGN: Five hundred and thirty-seven university undergraduates underwent cardiovascular reactivity testing. A serial-subtraction task served as the stressor. Reactivity was assessed as the difference between baseline and during-task levels, and recovery as the difference between baseline and post-stress levels. METHODS: The influence of sex, race and parental history of hypertension on reactivity and recovery was assessed, using analysis of variance models. RESULTS: No differences were found in reactivity for any of the factors. For recovery, a significant effect was found for parental history of hypertension on systolic blood pressure and a marginal effect on diastolic blood pressure. Post hoc tests revealed that values in groups with two hypertensive parents remained elevated at a significantly higher level than in offspring with either no or one hypertensive parent. CONCLUSION: Parental history of hypertension may affect the duration of the blood pressure response to an acute stressor more than the magnitude of the response.

Effects of racist provocation and social support on cardiovascular reactivity in African American women.

It has been speculated that exposure to the chronic stress of racism contributes to the high rates of hypertension among African Americans. Social support may buffer the effects of stress on cardiovascular (CV) health by attenuating stress-induced CV responses that have been linked to hypertension. In this study we investigated the effects of racism and social support on CV reactivity in African American women. Participants showed greater increases in CV and emotional responses while responding and listening to racist provocation. Augmented blood pressure (BP) persisted through recovery following racial stress. Participants receiving no support showed the greatest increases in anger during racist provocation. No significant effects were seen for support on CV reactivity. These results provide some of the first evidence that interactive confrontation with racism elicits significant increases in CV reactivity and emotional distress. Furthermore, individuals receiving less support may be at greater risk for the potentially health-damaging effects of racial stress. These findings may have significant implications for the health of African Americans.