Autonomic and Immuno-vascular Mechanisms of Antihypertensive Effects of Taichi

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 DESCRIPTION (provided by applicant): This is a revised version of 1R01HL126056-01. In response to reviewers we have better delineated potential pathways of blood pressure (BP) reduction by Tai Chi (TC), enhanced our control condition to increase active participation, narrowed our BP enrollment criteria (stage 1 and mild stage 2 hypertension) and extended our follow-up to 9 months. Hypertension (HTN) is a pervasive problem in the US and worldwide. Over 30% of American adults have HTN, with the incidence increasing substantially with age; 64% of men and 78% of women over 65 having HTN. HTN is one of the most important causes of premature death worldwide and one of the most significant preventable causes of death. Numerous clinical trials have revealed benefits of lowering BP for reductions in cardiovascular (CV) disease, CV-related death and stroke. Although pharmacologic therapy is often emphasized for HTN management, the importance of non-pharmacologic approaches is recognized for disease interruption and bears vast public health significance. There is growing evidence that TC is effective in lowering BP for patients with HTN, ranging 7 - 32 mm Hg SBP in the literature but is considered inconclusive due to reduced methodological quality of existing studies. Rigorously designed randomized and controlled trials are in great need. Furthermore, the mechanisms by which TC training reduces BP are unknown. The `neurogenic hypothesis' of HTN describes the imbalance owing to elevated sympathetic nervous system (SNS) activation and parasympathetic nervous system (PNS) impairment in HTN. TC practice is shown to reduce psychological distress such as anxiety and depression symptoms and reduce physiological arousal which can potentially improve autonomic balance, resulting in reduced BP. However, no prior studies have delineated the pathways through which TC reduces BP in HTN. Thus, we plan to investigate the underlying pathways among autonomic, vascular-dynamic, immuno-vascular and psychological alterations in relation to BP changes pre to post 12-week TC compared to a Healthy Aging Practice-centered Education (HAP-E) control condition. 250 older adults (60-80 years old) with stage 1 and mild stage 2 HTN will be enrolled, and baroreflex sensitivity, heart rate and BP variability and post-exercise HR recovery will be measured to examine autonomic regulation. Post TC autonomic "re-regulation" is hypothesized to mediate TC effects on BP and vascular health measured by pulse wave velocity (Aim 1) and inflammation regulation by sympatho-adrenergic system (Aim 2). Lastly, TC effects on autonomic regulation is hypothesized to be mediated by psychological factors (Aim 3). Findings from our randomized and controlled intervention study will shed light on the psycho-neuro-vasculo-immunological underpinnings of antihypertensive efficacy of TC. Also, we would clarify the unique effects of TC ("meditative movement") in an older, "hard-to-treat" hypertensive population that would particularly benefit from this behavioral therapeutic.