Bokhari S, Schneider RH, Salerno JW, Rainforth MV, Gaylord-King C, Nidich S. Effects of cardiac rehabilitation with and without meditation on myocardial blood flow using quantitative positron emission tomography: a pilot study. J Nucl Cardiol. Published online Sept. 16, 2019. doi: 10.1007/s12350-019-01884-9.
The researchers randomly divided study subjects into 4 groups: cardiac rehabilitation (CR), Transcendental Meditation (TM), cardiac rehabilitation plus Transcendental Meditation (CR+TM), or usual care.
Fifty-six African American patients with coronary heart disease, including recent heart attack, coronary artery bypass, or angina, were assigned to CR, CR+TM, TM alone, or usual care. Testing was done at baseline and after 12 weeks.
Participants were taught TM and instructed to practice for 20 minutes twice a day.
The primary outcome measured was myocardial flow reserve (MFR) assessed by 13N-ammonia positron emission tomography (PET). Secondary outcomes were coronary heart disease (CHD) risk factors. Based on guidelines for analysis of small pilot studies, the researchers analyzed data for effect size (ES).
Thirty-seven of the initial participants completed post-testing. Myocardial blood flow increased by 20.7% in the group that did both TM and cardiac rehabilitation. Blood flow in the group that practiced TM alone increased 12.8%. The group performing cardiac rehabilitation by itself showed an improvement of 5.8%. Patients who received the usual treatment showed a decrease in blood flow of –10.3%.
This was a proof-of-concept pilot study. It was the first to combine TM with other lifestyle treatment modalities like structured exercise and dietary counseling, and the first to use PET to measure the effect of mind-body lifestyle modification on cardiac function. The results suggest that adding TM to patients’ cardiac rehabilitation regime increased blood flow to the heart by 20.7% in those who completed the study.
Blood flow in the heart in the group that only practiced TM increased by 12.8%. Cardiac rehabilitation alone was associated with a 5.8% increase in flow. Patients who received only the usual standard-of-care treatments actually appear to have experienced a decrease of 10.3% in blood flow. For the group that combined cardiac rehab and TM, their MFR increased (+14%, ES=0.56). This was in contrast to the group that did not practice TM but did do cardiac rehab plus standard of care treatment: Their MFR actually decreased slightly (−2.0%, ES=− 0.08).
If we add these numbers together and compare the standard treatment received by most cardiac patients (-10.3% MFR) together with the improvements seen in the combined group that added cardiac rehab and TM to their care (+14% MFR), the results of this current study suggest that these combined therapies may improve cardiac blood flow by 24.3% over current standard care.
The PET scan method of measuring myocardial flow reserve is increasingly being used “to assess coronary artery disease, to guide revascularization decisions with more accuracy, and it allows robust quantitative analysis of both regional myocardial blood flow (MBF) and myocardial flow reserve (MFR).”1
Of course, one of the weaknesses of all these TM studies is the amount of personal contact that the TM practitioners receive from their instructors as they learn the technique. This attention might produce a placebo effect.
TM was brought to the West a half-century ago by the Indian Maharishi Mahesh Yogi. It became very popular in the 1960s and 1970s. Promoters of the practice early on adopted an idea that the technique could and should be evaluated scientifically and encouraged researchers to study the effect it had on practitioners.2 In 1971, Wallace, Benson, and Wilson were the first to describe in the scientific literature the wakeful hypometabolic state induced by the practice. The earliest clinical trial listed in PubMed is Dillbeck’s 1977 report that 2 weeks of practicing this meditation technique produced a significant decrease in measured anxiety compared to sitting with the eyes closed (N=33).3
Practitioners and researchers described a distinct state of consciousness induced by the practice that differs from sleeping, dreaming, and normal wakefulness, a state of restful alertness, what they label as a “fourth state of consciousness.”4 According to Mosini et al, “The purpose of meditation is the elimination or reduction of thought processes, the deceleration of the inner dialog of the mind. This reduction of the thought process aims to increase this state of higher consciousness and, thus, could lead to a great sense of physical and mental tranquility.”5
Research on TM has been aided by the comprehensive training program instructors undergo and the standardization of instruction. The resultant reproducibility of the meditation practice and the availability of subjects, along with active encouragement by the organization teaching the technique, led to the publication of a substantial body of scientific data describing the effects of the practice.
The hypothesis that practicing TM might reduce the risk of cardiovascular disease (CVD) was presented early on; randomized controlled trials of the effects of TM on hypertension were first published in the mid-1990s.6,7
In a 2004 review on TM and heart disease, Walton et al suggest that, at the time of publication, there was already a body of research on TM that comprised over 600 papers. They did not specify how many papers focused on heart disease. There have been at least 3 dozen papers on TM and heart disease published over the past 2 decades. In selecting the current study we’ve written about here, we considered half a dozen recent papers.
Over the years, a number of theories have been suggested to explain why TM might protect against heart disease, including this one from Walton et al:
“The Transcendental Meditation (TM) technique is distinct from other techniques of meditation not only in its origin and procedure, but also in the amount and breadth of research testing it. Evidence for its ability to reduce traditional and novel risk factors for CVD includes: 1) decreases in blood pressure, 2) reduced use of tobacco and alcohol, 3) lowering of high cholesterol and lipid oxidation, and 4) decreased psychosocial stress. Changes expected to result from reducing these risk factors, namely, reversal of atherosclerosis, reduction of myocardial ischemia and left ventricular hypertrophy, reduced health insurance claims for CVD, and reduced mortality, also have been found with TM practice. Research on mechanisms suggests that some of the CVD-related benefits as a result of this technique could arise from normalization of neuroendocrine systems whose function has been distorted by chronic stress.”8
Although those connected with the TM movement have long argued that the practice is distinct from other meditation techniques, the scientific literature often lumps all meditative techniques under similar headings. As a result, it is hard to distinguish which meditation practice exactly the practitioners were doing in studies. Thus, it is not always easy to discern whether a study is describing participants following “do it yourself” instructions (for example, those published in The Relaxation Response, by Herbert Benson, MD, in 1975, on how to imitate TM meditation), or those following online instructions for mindfulness meditation, or participants following some technique they learned at a yoga studio. Followers of Maharishi always insist that the TM technique they practice is unique and that these other practices do not have the same effects.
Neurohormonal effects of TM have been documented in numerous studies and were summed up by Newberg and Iversen in 2003. They reported that practicing TM increased gamma-aminobutyric acid (GABA), glutamate, and dopamine in the brain while decreasing cortisol and noradrenaline.9
The results reported in this current Bokhari study are in line with earlier publications. Data published in 2012 in Circulation also suggested a significant benefit. In a randomized controlled trial (N=201) of African Americans with CHD, following the primary endpoint of the composite of all-cause mortality, myocardial infarction, or stroke, there was a 48% reduction of the primary endpoint in the TM group during a 5.4-year follow-up.10
An October 2019 paper by Schneider et al, which described a randomized controlled trial, reported that TM prevented left ventricular hypertrophy. In this study, African American adults (N=85) were assigned to either a TM intervention or a health education control group. At baseline and 6-month follow-up, participants’ left ventricular mass indexes (LVMI) were compared. The TM group’s LVMI was significantly lower.11
TM researchers appear to routinely select African Americans as study participants for their cardiovascular studies. The authors of these studies explain their recurring choice to recruit African American participants as due to the fact that this population has a higher-than-average risk of heart disease and that this increase may in part be a result of psychosocial stress. Thus, a stress-reducing intervention might have a greater impact on their relative risk than it might on the general population.
Of course, one of the weaknesses of all these TM studies is the amount of personal contact that the TM practitioners receive from their instructors as they learn the technique. This attention might produce a placebo effect. Even if this were the case, one might still argue that the ends justify the means in that anything that reduces cardiovascular mortality to the extent reported with so little risk is desirable.
The other reservation that some may have about these research papers is that they are consistently done by adherents or proponents of this technique, and one might question their objectivity. Truthfully, similar questions about objectivity could be raised about a good percentage of other studies, especially when the research is sponsored by financial interests that desire specific outcomes.
The bottom line remains that practicing TM may help, and it is highly unlikely to hurt.
The American Heart Association came to a similar but more eloquently written conclusion in a 2017 position paper on meditation, writing in part:
“Studies of the effects of meditation on cardiovascular risk have included those investigating physiological response to stress, smoking cessation, blood pressure reduction, insulin resistance and metabolic syndrome, endothelial function, inducible myocardial ischemia, and primary and secondary prevention of cardiovascular disease. Overall, studies of meditation suggest a possible benefit on cardiovascular risk, although the overall quality and, in some cases, quantity of study data are modest. Given the low costs and low risks of this intervention, meditation may be considered as an adjunct to guideline-directed cardiovascular risk reduction by those interested in this lifestyle modification, with the understanding that the benefits of such intervention remain to be better established.”12
For those who would like to follow up on recommending TM, you can refer patients to the national organization’s website for further information about learning the technique and finding a certified instructor: TM.org