As a complement to standard medical care, we found that tai chi has potential clinical benefits including enhancement in quality of life, mood, and exercise self-efficacy, despite the absence of differential improvement in peak oxygen intake and 6-minute walk test compared with education only. While outcomes in these traditional exercise parameters did not change significantly between groups, the low-intensity tai chi program seems to have achieved other measurable training benefits, including increased daily activity (as measured by the CHAMPS questionnaire) and related feelings of well-being.
Our findings support those of prior studies of tai chi that also reported improvements in quality of life, mood (decrease in anxiety and enhancement in vigor), and exercise self-efficacy in other patient populations, including those with cardiovascular disease and cardiovascular risk factors.28,68
Because chronic systolic HF is a progressive and debilitating condition, the importance of beneficially affecting patient-perceived quality of life is increasingly appreciated. We observed large, clinically significant changes in quality of life in this study, similar to or even greater than what has been seen with cardiac resynchronization therapy.69
In addition, given the relationship between depression and HF, improvement in mood in this population is also highly relevant. While there were modest changes in measured exercise capacity, these cannot be attributed to tai chi, since the groups improved equally. It is possible that our education control group was motivated to increase their exercise level during the study period, accounting for their increase in exercise capacity, although this was not detected with the CHAMPS questionnaire. Direct comparisons are difficult; however, the magnitude of changes in exercise capacity seen at 12 weeks in this trial are similar to or larger than those reported with conventional exercise in the multicenter trial, HF-ACTION.7,8
One of the purported mechanisms of mind-body exercises, such as tai chi, is favorable modulation of the autonomic nervous system. In our post hoc analyses, we found that, in participants with higher resting heart rates (and presumably more sympathetic nervous system “overdrive”), there was a greater benefit with tai chi. The pilot study24
of tai chi in patients with HF reported larger changes in outcomes (improvements in quality of life, exercise capacity, and B-type natriuretic peptide). The mean resting heart rate in the tai chi group in that study was somewhat higher than that in the present study (75 vs 71 bpm), possibly contributing to the differences in findings between the 2 studies. These observations need further investigation but may offer insight into which sub-populations of patients may respond better to a mind-body exercise intervention.
Tai chi appears to be a safe alternative to low to moderate-intensity conventional exercise training in patients with HF. We observed no adverse events related to the intervention. Two prior trials21–23
in patients at higher risk (recovering from coronary bypass surgery and myocardial infarction) also reported no adverse effects. Apparent safety has also been reported among several other populations, including transitionally frail adults,35
patients with arthritis,70,71
and balance-impaired individuals with vestibular disease.52,72
This study has several limitations. First, patients were not masked to intervention group. However, we attempted to minimize the potential effects of disappointment in the education group by offering tai chi classes at the end of the 6-month follow-up period. Second, with a sample of 100 patients, only a small proportion of eligible patients enrolled in this trial, which could introduce selection bias. In addition, we are unable to provide a definitive physiological mechanism for tai chi’s effects. Nonetheless, this study provides informative data from the first large-scale clinical trial of tai chi exercise in an HF population.
In conclusion, tai chi exercise, a multicomponent mind-body training modality that is safe and has good rates of adherence, may provide value in improving daily exercise, quality of life, self-efficacy, and mood in frail, deconditioned patients with systolic HF. A more restricted focus on traditional measured exercise capacity may underestimate the potential benefits of integrated interventions such as tai chi.
Future steps should include research at both ends of the translational research continuum. At the pragmatic end, we might explore how these clinical observations translate into community-based programs, the feasibility of more wider spread implementation, and cost-effectiveness studies. At the basic science end, we need further study of the mechanisms by which tai chi benefits patients with cardiovascular disease and to better understand how the multiple components of tai chi (eg, deep breathing, aerobic exercise, cognitive restructuring, and social interactions) might affect various outcomes (eg, autonomic physiology, exercise capacity, or mood). This elucidation of plausible physiological mechanisms may allow us to better tailor our interventions, target subpopulations with specific constellations of symptoms, and further support clinical findings.