Does psychological stress contribute to the development of hypertension and coronary heart disease?

Immediate and long-term effects of psychological stress during adolescence in cardiovascular function: comparison of homotypic vs heterotypic stress regimens

Adolescence has been proposed as an ontogenic period of vulnerability to stress. Nevertheless, the impact of stressful events during adolescence in cardiovascular activity is poorly understood. Therefore, the purpose of this study was to investigate the immediate and long-lasting effects of exposure to stressful events during adolescence in cardiovascular function of rats. To this end, we compared the impact of 10-days exposure to two chronic stress protocols: the repeated restraint stress (RRS, homotypic) and chronic variable stress (CVS, heterotypic). Independent groups of animals were tested 24h (immediate) or three weeks (long-lasting) following completion of stress period. Exposure to CVS, but not RRS, during adolescence increased basal HR values without affecting arterial pressure, which was followed by augmented power of oscillatory component at low frequency (sympathetic-related) of the pulse interval (PI). RRS enhanced variance of the PI with an increase in the power of both low and high (parasympathetic-related) frequency components. RRS also increased the baroreflex gain. Neither RRS nor CVS affected systolic arterial pressure variability. The RRS-evoked changes in PI variability were long-lasting and persisted into adulthood while all alterations evoked by the CVS were reversed in adulthood. These findings indicate a stress type-specific influence in immediate and long-term effects of stress during adolescence in cardiovascular function. While immediate changes in cardiovascular function were mainly observed following CVS, long-lasting autonomic consequences in adulthood were observed only in animals exposed to RRS during adolescence.

Psychosocial determinants of hypertension: laboratory and field models

Tom Pickering had a profound influence on the study of biobehavioral factors in the development, diagnosis, and misdiagnosis of hypertension. His contributions influenced several avenues of research, including ecological momentary assessments of the sources and causes of diurnal blood pressure variation, the evaluation and impact of job strain on blood pressure and cardiovascular disease, and the role of blood pressure reactivity and recovery to acute stress in hypertension development. This overview approaches these topics by examining the seminal role of the work by Tom et al. in the current understanding of how biobehavioral factors contribute to hypertension.

An overview of essential hypertension in Americans as a multifactorial phenomenon: interaction of biologic and environmental factors

This paper reviews the current literature on essential/primary hypertension in terms of its expression as a multifactorial phenomenon. The genetic and environmental risk factors involved in expression of hypertension and their interactions are discussed. A specific mutation in epithelial sodium channels, T549M, is presented as a genetic risk factor for primary hypertension as expression of this mutation has been reported to result in hyperabsorption of sodium in homozygous individuals. T549M is used in this report to illustrate the multifactorial nature of primary hypertension. Possible interactions of T549M with environmental factors known to promote hypertension and the outcome of these interactions are discussed. Data indicates that both genetic and environmental risk factors must be considered to understand and intervene effectively with patients who have primary or essential hypertension.

Stress reduction and preventing hypertension: preliminary support for a psychoneuroendocrine mechanism

Our objective was to identify endocrine-related mechanisms capable of mediating preventive effects of stress reduction in hypertensive heart disease. Since beneficial effects of stress reduction accrue over time, this cross-sectional, descriptive study sought differences between healthy students not practicing a systematic technique for reducing stress (the average stress, or AS, group, n = 33) and a similar group who for 8.5 years had practiced the Transcendental Meditation (TM) technique, used widely to reduce stress (the low stress, or LS, group, n = 22). The two groups of students, matched for age and area of study, performed timed collections of urine that included (separately) the entire waking and sleeping portions of 1 day. They also completed the Profile of Mood States and the State-Trait Anxiety Inventory, self-report instruments sensitive to subjective level of stress. Urine samples were analyzed for adrenocortical steroids by radioimmunoassay, for Na+, K+, Mg2+, Ca2+, and Zn2+ by atomic absorption spectrometry, and for neurotransmitter metabolites by reverse-phase, high-performance, liquid chromatography, and spectrophotometry. The two groups differed significantly on most measures. Specifically, the LS group was lower in cortisol and aldosterone and higher in dehydroepiandrosterone sulfate (DS) and the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA). Excretion of sodium, calcium, zinc, and the norepinephrine metabolite, vanillylmandelic acid (VMA), was also lower in this group, as were Na+/K+ ratio, mood disturbance, and anxiety. In women practicing TM, cortisol correlated inversely and DS directly with number of months of TM practice. The results identify improvements in mood state, adrenocortical activity, and kidney function as probable factors in the preventive and treatment effects of stress reduction. Because suboptimal levels of these parameters result from chronic, subjective stress, the findings add mechanistic support to the contention that hypertensive heart disease is avoidable, even in modern industrialized societies.

Two faces of sympathetic nervous activity--hypotension and hypertension

The sympathetic nervous system may play a pivotal role in the development of primary (essential) hypertension, and is almost always involved in the increasingly common occurrence of postural hypotension. This report reviews the recent evidence for and against stress-induced activation of sympathetic activity leading to a hyperkinetic circulation as an initiating mechanism for most hypertension. Then, attention is directed to the role of altered sympathetic nervous system responsiveness in the development of postural hypotension. Finally, therapy for this syndrome is reviewed.