Voluntary Blood Pressure Control: Operant Conditioning by a Continuous Blood Pressure Feedback Technique

Abstract

The present study evaluated a single session operant conditioning of blood pressure in borderline hypertensives. A double blind randomized two period (each lasting for 20 minutes) cross over study consisting of a treatment (operant conditioning of mean arterial blood pressure) and a control condition (heart rate) was performed. Sequence of treatments was randomly assigned. Fourteen borderline hypertensive subjects participated and were trained to decrease their continuously measured blood pressure (Finapres) and heart rate. Subjects receiving blood pressure feedback during the first session showed a significant (4.3 mmHg) decrease in diastolic blood pressure. In contrast, subjects receiving blood pressure training during the second session showed a non-significant increase in diastolic blood pressure. Treatment consisting of more sessions is a promising adjunct to antihypertensive regimens.     

Blood pressure and personality

Three groups of 18-yr-old male Ss were selected from a representative Swedish population according to strict blood-pressure criteria: hypertensives (systotic blood pressure above 146 and diastolic above 90), on two occasions, normotensives (systolic blood pressure between 124 and 131, population mean = 128) and hypotensives (systolic blood pressure between 100 and 106). As a part of a broad multidisciplinary study, personality inventory scales and unpleasantness ratings for various types of situations were administered. The findings for the hypertensives indicated lower assertiveness and higher anxiety-proneness, whereas the hypotensives, compared to normotensives, showed a more impulsive, acting-out personality pattern. The hypertensive group was subdivided according to digital vasoconstriction criteria. The non-vasoconstricted subgroup showed a more impulsive and ‘anger-out’ personality pattern, whereas the pattern obtained in the vasoconstricted subgroup was more similar to the classical hypertensive personality, characterized by anxiety and unexpressed anger.     

Caffeine enhances the physiological response to occupational stress in medical students

Caffeine (3.3 mg/kg) was tested against a placebo in 20 male medical students during periods of low (no exams) versus high (final exams) work stress. On each of 8 test days, heart rate and blood pressure were measured at baseline and over a 40-min postdrug interval; immediately afterward, blood was drawn to test plasma cortisol and serum lipid concentrations. Exams increased heart rate (p less than .005) and systolic blood pressure (p less than .02). Caffeine decreased heart rate (p less than .0001) and increased systolic blood pressure (p less than .005), diastolic blood pressure (p less than .0001), plasma cortisol levels (p less than .01), and serum cholesterol levels (p less than .02). Caffeine effects were additive with those of exams, and together they increased the number of men showing systolic blood pressures in the borderline hypertensive range. Thus, caffeine use during periods of increased occupational stress may enhance the cumulative stress response.     

A longitudinal study of pain sensitivity and blood pressure in adolescent boys: results from a 5-year follow-up.

A growing literature has observed a significant reduction in pain sensitivity among hypertensive animals and humans. It is uncertain whether a reduced sensitivity to pain can be observed in nonnotensive individuals who go on to develop high blood pressure. Blood pressure (BP) was reassessed in one hundred fifteen 19-year-old boys initially tested at age 14, when they were also presented with a pain stimulus (mechanical finger pressure). Hierarchical regression analyses indicated that information regarding pain tolerance improved prediction of changes in systolic and diastolic blood pressure beyond that afforded by differences in BP at age 14, parental history of hypertension, and body mass index. These analyses suggest that pain sensitivity may be associated with physiological processes involved in the development of sustained high blood pressure.     

A homeostatic adaptive response to alpha-methyl-dopa in conscious dogs

Repeated daily administration of an oral dose of 1000 mg of alpha-methyl-dopa (methyl dopa) to conscious dogs produced a conditioned adaptive hypertensive systolic and diastolic arterial pressure response along with the direct hypotensive pharmacological effect. The lower dose of 500 mg/day appeared to be devoid of direct or adaptive response effects, while the higher dose of 2000 mg/day only produced a blood pressure lowering response. The abrupt drug withdrawal unmasking the homeostatic state resulted in a marked systolic and diastolic pressor response which endured for about 10-days with peak effect reached at 17-days after termination of drug treatment. Comparable results were obtained whether the dogs were evaluated while in their normal horizontal body position or in a repositioned upright condition.     

Links between physical fitness and cardiovascular reactivity and recovery to psychological stressors: A meta-analysis.

A meta-analysis of published studies with adult human participants was conducted to evaluate whether physical fitness attenuates cardiovascular reactivity and improves recovery from acute psychological stressors. Thirty-three studies met selection criteria; 18 were included in recovery analyses. Effect sizes and moderator influences were calculated by using meta-analysis software. A fixed effects model was fit initially; however, between-studies heterogeneity could not be explained even after inclusion of moderators. Therefore, to account for residual heterogeneity, a random effects model was estimated. Under this model, fit individuals showed significantly attenuated heart rate and systolic blood pressure reactivity and a trend toward attenuated diastolic blood pressure reactivity. Fit individuals also showed faster heart rate recovery, but there were no significant differences in systolic blood pressure or diastolic blood pressure recovery. No significant moderators emerged. Results have important implications for elucidating mechanisms underlying effects of fitness on cardiovascular disease and suggest that fitness may be an important confound in studies of stress reactivity.     

Cardiovascular reactivity to psychological stress in aerobically trained versus untrained mild hypertensives and normotensives

Cardiovascular reactivity to video game and mental arithmetic stressors was compared among three groups of men: aerobically trained mild hypertensives, untrained mild hypertensives, and a comparison group of untrained normotensives. Relative to the untrained hypertensives, the trained hypertensives reacted to the video game with marginally smaller systolic blood pressure and diastolic blood pressure, but there were no significant differences between these groups in reactivity during the mental arithmetic task. Comparisons between each hypertensive group and the normotensive group showed that blood pressure (BP) reactivity of normotensives during the video game was generally similar to that of trained hypertensives but smaller than that of untrained hypertensives. These results indicate that aerobic training, which has been found to reduce resting BP in mild hypertensives, may also exert a favorable impact in reducing cardiovascular reactivity of hypertensives during some stressful situations.     

Interactive but not direct effects of perceived racism and trait anger predict resting systolic and diastolic blood pressure in black adolescents.

This correlation study explicated the association of perceived racism and trait anger to resting blood pressure in a high school sample of 234 Blacks. Perceived racism and trait anger were assessed via self-report, and resting blood pressure was measured with a noninvasive blood pressure monitor. Hierarchical regression analyses indicated that perceived racism and trait anger were not independent predictors of systolic or diastolic blood pressure. However, these analyses revealed that the interactive effects of perceived racism and trait anger were predictive of systolic and diastolic blood pressure. Although perceived racism was not significantly related to blood pressure among those who were high in trait anger, perceived racism was inversely associated with blood pressure among those who were low in trait anger. The findings may have important longer term implications for future research examining the contribution of psychosocial factors to cardiac and vascular functioning in Blacks.     

Cardiovascular generalization and differentiation: The relationship between heart rate and blood pressure

The present study was designed to study generalization and differentiation and to check the relation between heart rate and blood pressure in cardiovascular conditioning. Five naive mongrel dogs were presented with 10 sec 1000 cps tone regularly reinforced with 0.5-sec shock to a left foreleg. Four other 10-sec tones (600, 800, 1200, 1400 cps), never reinforced, were administered in a randomized and counterbalanced fashion using a differential reinforcing technique. The response measures were heart rate and three indices of blood pressure,i.e., systolic, diastolic, and pulse pressures.“Initial response” of heart rate showed rapid tachycardia to all tones, with no generalization and differentiation among five tones.“Terminal response” clearly indicated generalization gradients that tachycardia to 800 and 1200 cps tones were higher than those to 600 and 1400 cps tones, respectively. Some differences were noted among systolic, diastolic, and pulse pressures, with pulse pressure showing a trend of generalization and differentiation in the“initial response.” No statistical difference, however, was obtained in blood pressure scores. Beat-by-beat analyses of correlations between heart rate and diastolic blood pressure showed that the correlations successively decreased during the“terminal response.” Overall correlations between heart rate and three indices of blood pressure were obtained, with the highest correlation between heart rate and pulse pressure. Considering the above results in relation to the classical conditioning theory, it was tentatively concluded that“initial response” includes non-conditional factors, while“terminal response” reflects mainly a true conditional response, particularly, at a long CS-US interval. This interpretation leads to the hypothesis that conditional response with a short CS-US interval may attain better conditioning scores in terms of the summation effect between a non-conditional factor and a true conditional factor.     

Anxiety management training in the treatment of essential hypertension

The study was conducted to assess the efficacy of Anxiety Management Training as an adjunctive treatment for essential hypertension. Twenty-one patients with essential hypertension, all but one of whom were on antihypertension medication, were randomly assigned either to an Anxiety Management Training condition or a waiting-list control condition. At the time of a posttest assessment session, compared to subjects in the control condition, subjects in the Anxiety Management Training condition manifested a decrease in resting systolic and diastolic blood pressure and a decrease in systolic and diastolic blood pressure following a stressful task. At the time of a follow-up assessment session, subjects in the Anxiety Management Training condition not only manifested good maintenance of reduced blood pressure but also exhibited a further decrease in resting systolic blood pressure and a decrease in systolic blood pressure during the stressful task.     

Exploring Emotion-Regulation and Autonomic Physiology in Metastatic Breast Cancer Patients: Repression, Suppression, and Restraint of Hostility

We examined relationships between three emotion-regulation constructs and autonomic physiology in metastatic breast cancer patients (N = 31). Autonomic measures are not often studied in breast cancer patients and may provide evidence of an increase in allostatic load. Patients included participated as part of a larger clinical trial of supportive-expressive group therapy. Systolic and diastolic blood pressure and heart rate were assessed at a semi-annual follow-up. We averaged 3 resting assessments and used measures of Repression, Suppression, Restraint of Hostility, and Body Mass Index as predictors of autonomic response. We found that higher repression was significantly associated with higher diastolic blood pressure, while higher restraint of hostility was significantly associated with higher systolic blood pressure. A repressive emotion regulation style may be a risk factor for higher sympathetic activation possibly increasing allostatic load, while restraint of hostility may be a protective factor for women with metastatic breast cancer.     

Cardiovascular and neuroendocrine activity in preschool children: Comparison between day-care and home levels

Thirty boys and 30 girls at nine day-care centers were examined at the mean age of 3.5 and 5.5 with regard to systolic and diastolic blood pressure, heart rate and neuroendocrine activity (urinary catecholamines and cortisol) during a day at their day-care center and in their home, respectively. Compared to home levels, day-care was associated with increased heart rate, epinephrine and norepinephrine excretion and decreased cortisol levels. Systolic blood pressure decreased at the day-care centers at the age of 3.5 and increased at the age of 5.5. No significant sex differences were found. The possible role of mental and physical arousal and the dissociation between the sympathetic-adrenal medullary and the pituitary-adrenal cortical responses are discussed.     

Nonlinear blood pressure effects on cognition in old age: separating between-person and within-person associations

Midlife hypertension is associated with increased risk of cognitive impairment in later life. The association between blood pressure (BP) in older ages and cognition is less clear. In this study we provide estimates of between-person and within-person associations of BP and cognition in a population-based sample (N = 382) followed from age 70 across 12 occasions over 30 years. Between-person associations refer to how individual differences in BP relates to individual differences in cognition. Within-person associations refer to how individual and time specific changes in BP relate to variation in cognition. Hierarchical linear models were fitted to data from three cognitive measurements (verbal ability, spatial ability, and perceptual speed) while accounting for demographic and health-related covariates. We found consistent nonlinear between-person associations between diastolic BP (DBP) and cognition, such that both low (<75 mmHg) and high (>95 mmHg) pressure were associated with poorer cognition. Within-person decreases in systolic BP (SBP) and DBP were associated with decreases in perceptual speed. Notably, between-person and within-person estimates did not reveal similar associations, suggesting the need to separate the two effects in the analysis of associations between BP and cognition in old age.     

Humor As a Stress Moderator in the Prediction of Blood Pressure Obtained during Five Stressful Tasks

In five consecutive stressful tasks we examined the role of humor as a potential stress moderator using systolic and diastolic blood pressure as an indication of cardiovascular reactivity. In all five tasks, the Coping Humor Scale interacted with sex in the prediction of blood pressure. The same pattern was found in response to each of the five tasks: Females who were higher in coping humor exhibited lower systolic blood pressure than females scoring lower on coping humor, while the reverse characterized males; males who scored high on the coping humor scale exhibited higher systolic blood pressure than males scoring low on that scale. Similar though less robust results were found when the Situational Humor Response Questionnaire was used as the measure of humor. In the Cold Pressor Task, which involves pain and endurance, interactions were found between humor, sex, and trials indicating a stress-moderator effect. The absence of interactions indicating stress moderation in most of the analyses with the other four stress tasks suggests that humor may play more of a role in moderating the impact of uncontrollable and passively experienced stressors. Tasks requiring more active, problem-solving behavior may be less amenable to the beneficial effects of humor. The findings do not clearly resolve the questions about the role of humor in effecting responses to stress. However, they do suggest that the subjects' sex may be an important consideration when evaluating the impact of humor as a stress moderator.     

The moderating effect of perceived organizational support on the relationships between organizational justice and objective measures of cardiovascular health

This paper builds on a recent meta-analytic review on the relationships between organizational justice and health. Specifically, we examine the moderating role of perceived organizational support (POS) on the relationships between organizational justice and three objective cardiovascular health measures, namely, heart rate, systolic blood pressure, and diastolic blood pressure, among a population of 290 public construction workers. The interaction between justice and POS was statistically significant using procedural justice, demonstrating that procedural justice is associated with improvements in the three health outcomes only when POS is relatively high. In other words, higher levels of both procedural justice and POS were needed for reduced heart rate and reduced systolic and diastolic blood pressure. However, the interaction between distributive justice and POS did not significantly relate to the health outcomes. This study makes a contribution to the field by focusing the effects of psychosocial workplace variables on measures of cardiovascular health, and demonstrating an important boundary condition of the relationships between procedural justice and cardiovascular risk factors.     

The effects of short term flotation REST on relaxation: a controlled study

The purpose of this study was to compare the effects of restricted environmental stimulation using a flotation tank (Flotation REST) to the effects of a normal sensory environment on relaxation. All of the subjects were first introduced to a simple relaxation program to be used during the experimental sessions. The program consisted of guided point-to-point relaxation, breathing techniques, and visual imagery techniques. Subjects were then pre-tested on measurements of electromyogram (EMG), galvanic skin response (GSR), peripheral skin temperature, and systolic and diastolic blood pressure. The experimental group experienced ten 45-minute sessions practicing the relaxation program in a Flotation REST environment. The control subjects practiced the same relaxation program in a similar body position for 45 minutes in a normal sensory environment. All subjects answered a five-question Subjective Relaxation Questionnaire on trials five through ten and were then post-tested on EMG, GSR, skin temperature, and blood pressure. The results indicated significant differences between groups from pre-test to post-test on systolic and diastolic blood pressure; the experimental group showed greater reductions. Significant differences also were observed on three of five questions on the Subjective Relaxation Questionnaire; the experimental group reported greater subjective relaxation and trends in a similar direction on the remaining two questions. The results of this study indicate that flotation REST enhances point-to-point relaxation, breathing techniques, and visual imagery techniques and, when combined with these techniques, can be an effective means of teaching normal subjects to lower systolic and diastolic pressure and heighten their subjective perception of relaxation.     

Auditory hallucinations in acute stroke

Auditory hallucinations are uncommon phenomena which can be directly caused by acute stroke, mostly described after lesions of the brain stem, very rarely reported after cortical strokes. The purpose of this study is to determine the frequency of this phenomenon. In a cross sectional study, 641 stroke patients were followed in the period between 1996-2000. Each patient underwent comprehensive investigation and follow-up. Four patients were found to have post cortical stroke auditory hallucinations. All of them occurred after an ischemic lesion of the right temporal lobe. After no more than four months, all patients were symptom-free and without therapy. The fact the auditory hallucinations may be of cortical origin must be taken into consideration in the treatment of stroke patients. The phenomenon may be completely reversible after a couple of months.     

THE EFFECTS OF FEEDBACK ON BLOOD PRESSURE DISCRIMINATION

Discrimination of blood pressure in the natural environment as a function of feedback was assessed. Seventeen normotensives screened for blood pressure lability were randomly assigned to two groups. These subjects were then asked to estimate their systolic and diastolic blood pressure values two times per day over a 4-week period. Feedback for accuracy of blood pressure discriminations was implemented across the two groups in a multiple baseline fashion, using a feedback withdrawal condition in Group I to assess maintenance effects over time. Results showed improvement in discrimination accuracy for subjects in both groups when feedback was used, and no decrement in performance over a 2-week period after feedback was removed for subjects in Group I. Discrimination of systolic pressures improved at a slightly faster rate than discrimination of diastolic pressures.