Objective: To determine the effects of yoga practice on subclinical cardiovascular measures, risk factors and neuro-endocrine pathways in patients undergoing cardiac rehabilitation (CR) following acute coronary events.
Design: 3-month, two-arm (yoga +usual care vs usual care alone) parallel randomised mechanistic study.
Setting: One general hospital and two primary care CR centres in London. Assessments were conducted at Imperial College London.
Participants: 80 participants, aged 35-80 years (68% men, 60% South Asian) referred to CR programmes 2012-2014.
Intervention: A certified yoga teacher conducted yoga classes which included exercises in stretching, breathing, healing imagery and deep relaxation. It was pre-specified that at least 18 yoga classes were attended for inclusion in analysis. Participants and partners in both groups were invited to attend weekly a 6- to 12-week local standard UK National Health Service CR programme.
Main outcome measures: (i) Estimated left ventricular filling pressure (E/e'), (ii) distance walked, fatigue and breathlessness in a 6 min walk test, (iii) blood pressure, heart rate and estimated peak VO2 following a 3 min step-test. Effects on the hypothalamus-pituitary-adrenal axis, autonomic function, body fat, blood lipids and glucose, stress and general health were also explored.
Results: 25 participants in the yoga + usual care group and 35 participants in the usual care group completed the study. Following the 3-month intervention period, E/e' was not improved by yoga (E/e': between-group difference: yoga minus usual care:-0.40 (-1.38, 0.58). Exercise testing and secondary outcomes also showed no benefits of yoga.
Conclusions: In this small UK-based randomised mechanistic study, with 60 completing participants (of whom 25 were in the yoga + usual care group), we found no discernible improvement associated with the addition of a structured 3-month yoga intervention to usual CR care in key cardiovascular and neuroendocrine measures shown to be responsive to yoga in previous mechanistic studies.
Trial registration number: NCT01597960; Pre-results.
Keywords: blood pressure; cardiac rehabilitation; exercise; heart rate; yoga.
© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. Published by BMJ.