Mechanisms of Meditation in Hypertension in Blacks

描述（由申请人提供）：与白色美国人相比，非洲裔美国人的高血压更普遍，开始于更早的年龄，往往更严重，更频繁地未被诊断和治疗。先前的研究表明，高水平的心理社会和环境压力导致了这一少数民族人群中高血压的不成比例的发病率。这种效应的机制包括过度的交感神经系统激活和心血管反应性。该中心团队先前在患有高血压的非洲裔美国人中进行的随机对照试验表明，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相关。这种效果可能有助于降低心血管疾病的发病率和死亡率在临床试验中观察到的非裔美国人使用冥想。然而，关于这种临床效应的生理机制的数据很少。因此，本研究的总体目标是调查急性和慢性影响冥想对心血管和自主神经系统机制的高血压在这个高风险的少数群体。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洲裔美国成年人将被分配到TM计划或HE对照组三个月。实验方案将在实验室中测试临床BP、动态BP以及对应激的慢性和急性生理反应。急性实验室应激源包括心算、冷加压和跑步机运动。具体而言，我们将评估心血管和血浆儿茶酚胺对实验室应激源的反应;血流动力学反应，包括心率、血压、每搏输出量、心输出量和总外周阻力;动脉顺应性和使用心率变异性的心脏自主神经系统张力。实验室血压模式将与自然环境中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）将通过回归模型对干预变量效应进行标准中介分析。这项研究的结果将提供急需的心血管，神经内分泌，自主神经和行为机制的数据，通过这些机制，减压干预可能会降低血压，从而预防和治疗高血压在这个非洲裔美国人的人口。 该应用程序有几个优势，包括调查团队的专业知识，研究人员先前工作的扩展，理解所涉及的潜在生物学，行为和心理社会因素的“翻译”方法，使用理论上强有力的措施，随机对照研究设计，以及研究成功完成的可能性很高。然而，有几个小的研究设计问题，似乎都可以补救。对这一应用的总体热情仍然很高。

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.