Mechanisms of Meditation in Hypertension in Blacks

描述（由申请人提供）：与美国白人相比，非裔美国人的高血压更普遍，发病年龄更早，往往更严重，更经常未得到诊断和治疗。先前的研究表明，高水平的社会心理和环境压力导致了这一少数群体中高血压的不成比例的比例。这种作用的机制包括过度的交感神经系统激活和心血管反应。先前由中心团队在非裔美国高血压人群中进行的随机对照试验表明，在短期和长期随访期间，与健康教育控制（HE）干预相比，超觉静坐（TM）计划的减压干预与降低血压水平有关。在非裔美国人使用冥想的临床试验中观察到，这种效果可能有助于降低心血管发病率和死亡率。然而，缺乏关于这种临床效果的生理机制的数据。因此，本研究的总体目的是探讨冥想对高血压高危少数人群心血管和自主神经系统机制的急性和慢性影响。这将是一项随机对照机制试验，152名40岁及以上的高血压非裔美国成年人将被分配到TM项目或HE对照组，为期3个月。实验方案将在实验室测试临床血压、动态血压以及对压力的慢性和急性生理反应。急性实验室压力源包括心算、冷压和跑步机。具体来说，我们将评估心血管和血浆儿茶酚胺对实验室压力源的反应性；血流动力学反应，包括心率、血压、卒中量、心输出量和总外周阻力；动脉顺应性和心脏自主神经系统张力利用心率变异性。实验室血压模式将与自然环境下的动态血压监测进行比较。干预影响血压的可能介质（即心理社会因素、行为因素、自主神经张力、CV反应性和血流动力学因素）将通过回归模型进行干预变量效应的标准介质分析进行研究。这项研究的结果将为心血管、神经内分泌、自主神经和行为机制提供急需的数据，通过减压干预可能降低血压，从而预防和治疗非裔美国人的高血压。

DESCRIPTION (provided by applicant): Hypertension is more prevalent, starts at an earlier age, tends to be more severe and more frequently remains undiagnosed and untreated in African Americans compared to white Americans. Previous studies indicate that high levels of psychosocial and environmental stress contribute to these disproportionate rates of hypertension in this minority population. Proposed mechanisms for this effect include excess sympathetic nervous system activation and cardiovascular reactivity. Previous randomized controlled trials in African American populations with high blood pressure conducted by the Center team have demonstrated that stress reduction intervention with the Transcendental Meditation (TM) program is associated with reduced blood pressure levels compared to health education control (HE) intervention over short and long-term follow-up periods. This effect may contribute to reduced cardiovascular morbidity and mortality rates observed in clinical trials with African Americans using meditation. However, there is a paucity of data on the physiological mechanisms for this clinical effect. Therefore, the overall objective of this study is to investigate acute and chronic effects of meditation on cardiovascular and autonomic nervous system mechanisms of high blood pressure in this high-risk minority population. This will be a randomized controlled mechanistic trial of 152 hypertensive African American adults 40 years and older who will be allocated to either the TM program or a HE control group for three months. The experimental protocol will test for clinic BP, ambulatory BP, and chronic and acute physiological responses to stress in the laboratory. Acute lab stressors will include mental arithmetic, cold pressor and exercise treadmill. Specifically, we will assess cardiovascular and plasma catecholamine reactivity to lab stressors; hemodynamic responses, comprising heart rate, blood pressure, stroke volume, cardiac output, and total peripheral resistance; arterial compliance, and cardiac autonomic nervous system tone using heart rate variability. Laboratory blood pressure patterns will be compared with ambulatory blood pressure monitoring in the naturalistic environment. Possible mediators through which the intervention affects blood pressure (i.e., psychosocial factors, behavioral factors, autonomic tone, CV reactivity and hemodynamic factors) will be investigated standard mediator analyses for intervening variable effects with regression models. The results of this study will provide much needed data on cardiovascular, neuroendocrine, autonomic and behavioral mechanisms by which a stress reduction intervention may lower blood pressure and thereby prevent and treat hypertension in this African American population. The application has several strengths including the expertise of the investigative team, previous extension of the investigator's prior work, a "translational" approach to understanding the underlying biological, behavioral, and psychosocial factors involved, use of measures which are theoretically strong, the randomized controlled study design, and the high likelihood that the study will be successfully completed. However, there are several minor study design issues that all appear remediable. Overall enthusiasm for this application remains high.