Yoga in Altering Mechanistic Outcomes in Hypertension

Study Overview
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Brief Summary
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The proposed study will assess the effects of yoga postures and slow, deep breathing in altering oxidative stress, vascular function, and blood pressure.

Detailed Description
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The purpose of this study is to determine the mechanism by which yoga lowers blood pressure in hypertensive adults. Free radicals and enzyme activity will be analyzed from isolated immune cells and blood pressure and vascular health will be assessed at baseline and at weeks 4, 8, and 12 during the interventions or control conditions. Sedentary adults (ages 40-60 years) with elevated blood pressure or stage I hypertension will be recruited and randomized to 12 weeks of yoga, slow, deep breathing, or waitlist control conditions. Yoga classes will be completed 3 times weekly at Texas State University and slow, deep breathing interventions will be completed at home 5 times weekly. Participants assigned to the waitlist/sham control group will also complete 5- 20-minute breathing exercises per week at home before being re-randomization at week 12. Three testing sessions will be completed at the beginning of the study: 1) familiarization and screening for elevated blood pressure or hypertension and other exclusion criteria; 2) confirmation of elevated blood pressure or hypertension via addition seated blood pressure measurements and 24-hour ambulatory blood pressure and 3-day physical activity monitoring; and 3) blood marker assessment and endothelial function measurements. All outcomes will be measured at baseline and at 4-week intervals throughout the 12-week data collection period in all 3 groups. At each follow up visit after randomization, testing will be completed over the course of 2 sessions: 1) ambulatory blood pressure monitor and physical activity monitoring and 2) blood marker and endothelial function measurements. At the end of the waitlist sham/control period, waitlisted participants will be rerandomized to yoga or slow, deep breathing interventions. Once re-randomized, participants in each group will complete follow up testing 4,8, and 12 weeks into their respective interventions.

Official Title
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Yoga Postures and Slow, Deep Breathing in Altering Mechanistic Outcomes in Hypertension

Conditions
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Hypertension

Intervention / Treatment
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* Behavioral: Yoga
* Behavioral: Slow, deep breathing
* Behavioral: Control breathing


Participation Criteria
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Eligibility Criteria
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Exclusion Criteria: pregnancy (tests will be administered to all premenopausal females at initial screening and follow up visits); having taken blood pressure or statin medications within the past 3 months (statins have been demonstrated to reduce oxidative stress); infection (viral or other) within the past 4 weeks; having adrenal or endocrine tumors (these could impact blood pressure); renal disease defined as an estimate glomerular filtration rate (eGFR) of less than 60 (creatinine will be tested at initial screening and eGFR will be calculated); hyperaldosteronism; prior myocardial infarction; known coronary heart disease; personal history of stroke; heart failure; cardiac arrhythmias; chronic obstructive pulmonary disease, asthma, or other airflow obstructions; recent chest pain or dyspnea; orthopedic limitations that preclude the execution of yoga postures; current insulin dependence; xvi) chronic inflammatory conditions (e.g., rheumatoid arthritis, lupus, HIV/AIDS, ulcerative colitis, or Crohn's disease); currently taking steroid or other anti-inflammatory medication; currently undergoing chemotherapy or radiation; having practiced yoga or slow, deep breathing at least once weekly within the past 6 months; or currently smoking or having quit within the last 6 months.

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Yoga postures or slow, deep breathing<br> | Behavioral: Yoga<br>* 12-week yoga intervention in which 60-minute classes are completed at Texas State University 3 times per week<br>Behavioral: Slow, deep breathing<br>* 12-week home-based intervention in which 5 weekly 20-minute breathing sessions are completed<br>|
| Sham Comparator: Control<br> | Behavioral: Control breathing<br>* 12-week home-based intervention in which 5 weekly 20-minute breathing sessions are completed<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in peripheral blood mononuclear cell reactive oxygen species | Blood draws will be performed at baseline and at weeks 4, 8, and 12 during the study after randomization and analyzed for free radicals after white blood cells are separated from whole blood. | Baseline and week 4, 8, and 12 measurements | 
| Change in peripheral blood mononuclear cell NADPH oxidase cell NADPH oxidase enzyme activity | A portion of the white blood cells isolated from a whole blood sample will be frozen and later analyzed for enzyme activity. This will be completed for blood samples obtained at baseline and weeks 4, 8, and 12. | Baseline and week 4, 8, and 12 measurements | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in 24-hour blood pressure | An automated cuff will be worn for 24 hours while the devices takes automatic measurements every 30 minutes. | Baseline and week 4, 8, and 12 measurements | 
| Change in flow-mediated dilation | A cuff will placed around the forearm while an ultrasound probe is held on the upper arm to obtain a brachial artery image. The forearm cuff will be inflated for 5 minutes, then ultrasound images of the upper arm will be obtained for 3 minutes after cuff deflation. | Baseline and week 4, 8, and 12 measurements | 
| Change in microvascular endothelial function/thermal hyperemia | A small probe will be secured on the forearm and gradually heated for 45 minutes. | Baseline and week 4, 8, and 12 measurements |