Psychophysiologic stress testing as a predictor of mean daily blood pressure

Laboratory-based blood pressure recovery is a predictor of ambulatory blood pressure

The recovery phase of the stress response is an individual difference characteristic that may predict cardiovascular risk. The purpose of this study was to examine whether laboratory-based blood pressure (BP) recovery predicts ambulatory BP (ABP). One hundred and eighty-two participants underwent a standard laboratory stress protocol, involving a 20-min baseline rest period, and four stressors presented in a counterbalanced order, each followed by a 10-min recovery period. Participants also wore an ABP monitor for 24h during a typical workday. Hierarchical regression analyses showed that BP recovery accounted for significant additional variance for daytime SBP (p<0.001), nighttime SBP (p<0.001), daytime DBP (p<0.001), and nighttime DBP (p<0.001), after controlling for baseline and reactivity BP. Results suggest that persistence of the BP response following stress may be a more salient characteristic of the stress response in understanding its potential impact on longer term cardiovascular regulation.

Blood pressure response to hyperventilation test reflects daytime pressor profile

Recent studies show that healthy subjects and patients with moderate hypertension have different pressor responses to hyperventilation, depending on their sympathoadrenergic reactivity. In the present study, we investigated whether a different response to the hyperventilation test is related to differences in the daily blood pressure profiles recorded with noninvasive ambulatory monitoring. Forty-five healthy subjects and 67 patients with essential hypertension of grades 1 and 2 (Joint National Committee VI and World Health Organization) were investigated. Healthy subjects and hypertensive patients responding to hyperventilation with an increase in systolic blood pressure had, during daytime ambulatory blood pressure assessment, peak systolic blood pressure values (146.0+/-5.0 mm Hg, 182.2+/-9.0 mm Hg, respectively) similar to the hyperventilation peak systolic blood pressure values (147.2+/-3.5 mm Hg, 183.0+/-4.7 mm Hg, respectively). Hypertensive patients responding to hyperventilation with a decrease in blood pressure showed clinic systolic blood pressure values (178.4+/-3.2 mm Hg) higher than daytime average ambulatory systolic blood pressure (155.2+/-7.1 mm Hg; P<0.01). Our results indicate that a hyperventilation test yields information on daily peak blood pressure values in healthy subjects and hypertensive patients when it induces a pressor increase and can identify hypertensive patients with the so-called "white coat effect" when it induces a pressor decrease.

[Cardiovascular impact of psychological stress]

The cardiovascular impact of stress depends on, first individual perception of stress and second individual cardiovascular reactivity to a stressful stimulation. Psychological stressors are filtered by cognitive appraisal mechanisms before causing biological response so that, for the same strain, individual effects may differ. Therefore, due to complexity of stress personal management, a multilevel stress measurement strategy is needed. To measure stress cardiovascular impact, stress should be precisely quantified. Recently, questionnaires have been developed to score not only the strain but also the personal perception of the strain. Individual stress reactivity can be evaluated by hormone response (epinephrine, norepinephrine, steroids) or by cardiovascular reactivity to a stress test. Until now, all the studies found that stress was independently related to blood pressure especially in active people. Prospective studies are still ongoing to definitively prove that stress could explain hypertension in a subset of hypertensives.

Office and laboratory blood pressures as predictors of daily blood pressure level in normotensive subjects and borderline and mild hypertensive subjects

A series of standardized laboratory tests [10 min sitting and supine, 9 min standing, dynamic; cycle ergometer (ERG) and isometric exercise; handgrip (HG)] were performed during intra-arterial blood pressure (BP) recording in 97 healthy unmedicated men, initially classified as normotensive (NT, n = 34), borderline hypertensive (BHT, n = 29) or mildly hypertensive (HT, n = 34) by repeated office blood pressure (OBP) measurements. After testing, a 24-h intra-arterial ambulatory BP (IABP) recording was obtained while subjects performed their normal activities. Day and night periods were analysed as well as 24-h averages for systolic BP (SBP) and diastolic BP (DBP) using Pearson correlations and multiple linear regressions. In normotensive subjects, the supine SBP predicted IABP measurements best (r range 0.39-0.69, P < 0.05-0.001). In multiple regression, supine SBP explained 49% of 24-h SBP variance (F = 12.4, P = 0.001). For BHT, supine SBP was also the best predictor (r range 0.09-0.64, P NS to P < 0.001), and it explained 37% of 24-h SBP variance (F = 15.6, P = 0.0005). In HT, ERG DBP correlated best with IABP (r range 0.52-0.75, P < 0.01-0.001). ERG SBP explained 49% of 24-h SBP (F = 31.0, P = 0.0000) and ERG DBP explained 56% of 24-h DBP (F = 35.4, P = 0.0000) variance. Laboratory BP correlations were generally better with day than with night measurements. OSBP correlated moderately well with IABP in NT, and weakly in BHT and HT; ODBP instead correlated with IABP in NT and HT but not significantly in BHT. In conclusion, OBP is less closely related to IABP than laboratory BP, but even laboratory BP generally explains less than 50% of IABP variance. Stressors such as exercise are useful only in HT. For BHT, the prediction of IABP with laboratory measures was even weaker than in other groups, and thus ambulatory measurements cannot be replaced by short-duration laboratory measurements and stress tests.

Blood pressure response to stress tests does not reflect blood pressure variability and degree of cardiovascular involvement in young hypertensives

The aim of the study was to assess the clinical value of blood pressure response to stress tests and to study its relationship with ambulatory blood pressure monitoring, daily blood pressure variability and hypertensive complications. Cold pressor test for 2 min, hand grip test at 25% of maximal voluntary contraction for 5 min and orthostatism were performed in 223 young men found hypertensive (BP systolic > 140 mmHg and/or diastolic > 90 mmHg) at the military service recruitment check-up. On the basis of ECG and fundoscopic examination, each patient was attributed a score of target organ damage. All patients underwent non-invasive 24-h blood pressure monitoring and 169 patients underwent echocardiographic examination. Hypertension was confirmed in 54.2% of the subjects at ambulatory monitoring. No correlation was found between blood pressure response to stress tests and ambulatory blood pressure, daily blood pressure variability, target organ damage and left ventricular mass. Night-time ambulatory blood pressure were correlated with posterior wall thickness/ventricular diastolic internal diameter ratio (r = 0.26, P < 0.001). A negative correlation was found between the office-daytime blood pressure difference and systolic and diastolic response to orthostatic test (r = -0.309, P < 0.0001 for systolic blood pressure and r = -0.433, P < 0.0001 for diastolic blood pressure) and between supine office blood pressure and blood pressure response to orthostatism (r = -0.186. P = 0.013 for systolic blood pressure and r = -0.442, P < 0.0001 for diastolic blood pressure).(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between 24-hour ambulatory blood pressures and laboratory measures of cardiovascular reactivity

The relationship between 24-hour ambulatory blood pressures (ABP) and blood pressures (BP) obtained during laboratory stressors was examined. Thirty normotensives (equal males and females) underwent ABP monitoring on three occasions separated by a week. They also underwent a laboratory assessment which included standard stressors (i.e., mental arithmetic, cold pressor, orthostatic response, treadmill exercise). Correlational analyses found laboratory pressures to be significantly correlated with ambulatory pressures, with laboratory baseline BPs showing higher correlations to the ambulatory BPs than the BPs obtained during laboratory stressors. In addition, gender effects were examined. In the correlational analyses between ABPs and laboratory BPs, males and females did not differ significantly in the strength of the correlations. In terms of absolute values, males were found to have significantly higher SBP during ambulatory monitoring, random-zero recordings, calibration readings, and during baselines of the laboratory assessment. There were no gender effects for these measures with respect to diastolic blood pressure or heart rate. There were also no gender effects on reactivity to laboratory stressors as measured by change scores. Exploratory analyses found no significant effect of history of familial hypertension on either the ABPs or the laboratory pressures.

Effects of psychological stress on cold pressor test results

The authors evaluated the incidence of a psychological stressor in the modification of blood pressure induced by the cold pressor test in normotensive and medicated hypertensive subjects. The study was carried out in two stages: In the first, 28 (14 normotensive and 14 hypertensive) subjects were administered a cold pressor test. Fifteen days later, 14 subjects repeated the same experiment. The remaining 14 subjects (7 hypertensive and 7 normotensive) also repeated the cold pressor test, with the difference that, to add a stressful psychological situation, the physician "abandoned" them at the beginning. The addition of the psychological stress significantly increased only systolic blood pressure in both the hypertensive and the normotensive subjects. Furthermore, the hypertensive subjects did not recover their basal blood pressure values following the cold pressor test when the psychologically stressful situation had been added. These results show the importance of considering psychological aspects when applying physical pressor tests.

Stress and the heart. Mechanisms, measurement, and management

Unrelieved physical or mental stress and repeated episodic stress are ultimately harmful to the cardiovascular system and thus can be life-threatening. In this article, Dr Eliot describes efforts to quantify the psychophysiologic responses to stress and to identify the components of stress and its clinical consequences. He also explains the importance of controlling the real-life episodic fluctuations in blood pressure that occur daily in response to stress.

Response to mental and physical stress before and during adrenoreceptor blocker and angiotensin-converting enzyme inhibitor treatment in essential hypertension

The effects of mental, static and dynamic stresses on physiologic parameters before and after beta-blocker (n = 24) and angiotensin-converting enzyme inhibitor (n = 29) treatment were examined. Mental stress induced similar elevation in systolic and diastolic blood pressures (BPs) with and without beta-blocker treatment. During angiotensin-converting enzyme inhibitor treatment, the change in systolic BP was significantly greater (p less than 0.05). Heart rate response was attenuated by beta blockers and unchanged by the angiotensin-converting enzyme inhibitor. Skin temperature and galvanic skin resistance significantly decreased (p less than 0.05) with mental stress. Beta blockers did not change the response pattern, whereas the angiotensin-converting enzyme inhibitor attenuated the stress-induced reduction of both skin temperature and galvanic skin response. After handgrip exercise, increases in systolic and diastolic BPs and heart rate were similar before and after beta-blocker treatment, whereas the angiotensin-converting enzyme inhibitor induced small but significantly fewer (p less than 0.05) changes in diastolic BP and heart rate. Treadmill exercise induced similar changes in systolic and diastolic BPs with both treatments compared with no treatment. The angiotensin-converting enzyme inhibitor appears to provide additional protection to that seen with beta blockers during mental and static stressors by blunted changes in skin temperature and galvanic skin resistance.

Cardiovascular responses in the laboratory and in the natural environment: is blood pressure reactivity to laboratory-induced mental stress related to ambulatory blood pressure during everyday life?

Cardiovascular activity recorded at rest and during mental stress in the laboratory was studied in relation to ambulatory recorded cardiovascular activity at work and at home. Fifty-five Type A men (M = 42.4 years) underwent a standardized laboratory mental stress protocol in which systolic blood pressure, diastolic blood pressure, and heart rate were recorded at baseline and during a 15 min mental arithmetic task (MAT). On a subsequent day, ambulatory blood pressure and heart rate were recorded at 20 minute intervals for 12-14 hr during normal activities at home and at work. Subjects completed a behavioral diary concurrently with each cuff inflation. High and Low groups were identified based upon a median split of their cardiovascular response levels at baseline and during the MAT. Subjects with high systolic blood pressure levels during the MAT had high systolic blood pressure at home, at work, during physical activity, and when they reported being 'stressed'. Baseline systolic blood pressure in the laboratory was less consistently related to ambulatory systolic pressure across ambulatory conditions. Diastolic blood pressure at baseline was related to ambulatory diastolic blood pressure at work, at home, and when resting. Diastolic blood pressure during the MAT was associated with higher diastolic pressure at work and at home. Heart rate at baseline and during the MAT was related to heart rate at work and during physical activity. Change scores derived by subtracting mean values during the MAT from baseline resting levels were not associated with ambulatory blood pressures or heart rates under any daily conditions. In the best case, systolic blood pressure measured during the MAT was related to systolic blood pressure during physical activity, to systolic blood pressure and heart rate during mental stress, to systolic and diastolic blood pressure at rest, and to systolic blood pressure and heart rate at work but not at home. We conclude that levels of blood pressure and heart rate measured in the laboratory, but not reactivity (i.e, change scores) during the MAT, are related to blood pressure and heart rate levels recorded in the natural environment, especially in the work setting.

The dynamics of hypertension--an overview: present practices, new possibilities, and new approaches

Contemporary clinical evaluation of hypertensive patients must include observations encompassing the impact of environment, behavior, and sociologic factors on metabolism and physiology. As evidenced by animal and human studies, catecholamines are an important mediator between psychologic factors and cardiovascular physiology, but direct measurement of catecholamine levels has not proved useful. Measurement of hemodynamic variables--blood pressure, heart rate, and stroke volume--during standardized psychophysiologic challenges is advocated. With low-challenge standardized stressors that include alpha- and beta-adrenergic stimuli, inappropriate reactors can be classified according to whether blood pressure is elevated primarily by cardiac output, total systemic resistance, or a combination of both. Hypertensive patients can be similarly distinguished, and medication can then be custom-tailored to the underlying physiology. Extensive laboratory and clinical evidence points to significant interrelationships between the central nervous system and the cardiovascular system. Furthermore, cardiovascular physiologic and metabolic perturbances are distinctly different under conditions of mental vs physical stress. Most clinical testing assesses physical performance whereas the real-life challenges of today are primarily mental.