Mechanisms of the Relaxation Response in Elderly Hypertensives

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DESCRIPTION (provided by applicant): Systolic Hypertension is a disorder which is characterized by significant elevations in systolic blood pressure in association with normal diastolic blood pressure. Typically, this develops in individuals >50 years of age and is associated with an increased risk of stroke and myocardial infarction. While there are many effective therapies for essential/diastolic hypertension, the treatment of systolic hypertension is complicated by side effects from traditional therapies. This limits therapeutic options and has resulted in a number of at-risk individuals being left untreated. We have recently completed a preliminary study showing that 8-weeks of relaxation response (RR) training significantly reduced systolic blood pressure in individuals with SH. Systolic blood pressure was significantly decreased by 9.4 mmHg and pulse pressure by 7.9 mmHg. This finding would suggest that the RR may be an effective intervention with few to no adverse consequences in this patient population. In other experiments, we found that the RR increased exhaled nitric oxide in young adult volunteers and plasma nitric oxide in female volunteers. Since nitric oxide levels are low in some patients with essential hypertension, abnormalities in nitric oxide availability could be contributing to SH and might be altered by the RR. However, the actual mechanism by which the RR affects SH remains undetermined. Since the RR is known to alter sympathetic responses, this may be one mechanism which explains the effect of the RR on SH. Other mechanisms contributing to this effect could include alteration of vascular function via changes in nitric oxide production or hormonal alterations in sympathetic arousal (i.e., stress response). We hypothesize that the RR reduces systolic blood pressure and pulse pressure without significant side effects and that this occurs by increasing nitric oxide production and/or by reducing stress hormone levels (epinephrine and cortisol). To examine this hypothesis, we propose conducting a randomized, controlled trial (n=90) in which older adults with SH will receive either 8-weeks of RR intervention or Health Education (HE). The primary outcome is change in systolic blood pressure and pulse pressure. Secondary outcomes are changes in nitric oxide, stress hormones and psychological well-being. Additional analyses will be conducted to assess for other confounding effects on BP and PP. Aim 1: Assess if an 8-week RR intervention will decrease systolic blood pressure and pulse pressure compared with HE (control) without significant side effects. Aim 2: Evaluate whether 8-weeks of RR training increases levels of nitric oxide compared with HE. Aim 3: Assess whether 8-weeks of RR training decreases stress hormones (epinephrine and cortisol) and improves psychological well-being (global severity index and anxiety) compared with HE. While elevated systolic blood pressure and pulse pressure are important risk factors for cardiovascular events, concerns about side effects leave many physicians reluctant to treat this condition. Given the challenges of controlling systolic blood pressure pharmacologically and the prevalence of side effects produced by many antihypertensive agents, identification of non-pharmacologic approaches to decrease systolic blood pressure in older Systolic Hypertension (defined as SBP >140 mm Hg with normal diastolic blood pressure (DBP <90 mm Hg) patients could contribute significantly to the treatment of this condition. These positive effects could have significant economic implications by providing a low-cost adjunctive therapy to current pharmacologic approaches and potentially reduce the incidence of cardiovascular events.