Benefits of tai chi in chronic heart failure: Body or mind?

Abstract

Aerobic exercise training has been demonstrated to yield a range of benefits for patients with chronic heart failure, including improvements in exercise capacity, health-related quality of life, left ventricular hemodynamics and geometry, and a decreased risk of hospitalization and death (1‐ 4). Although most studies have been performed with walking or cycling as the primary mode of exercise, much question remains about the optimal type of physical activity for these patients, most of whom are in their older years of life. Yeh and colleagues (5) present data in this issue of The American Journal of Medicine suggesting functional and biologic benefits of tai chi during a 3-month period in stable patients with systolic left ventricular dysfunction (mean age, 64 years). Although peak oxygen uptake did not improve after tai chi exercise compared with usualcare controls, the tai chi group showed improvements in 6-minute walk distance, self-reported quality of life as measured by the Minnesota Living with Heart Failure Questionnaire, and lower levels of brain natriuretic peptide (BNP). Whether these benefits relate to physical or psychologic effects of tai chi is not clear. The baseline aerobic capacity of the 30 patients in this study was extremely low, measured at 10.5 3 mL/kg/min, and this capacity did not increase after the tai chi program. Thus, the perceived benefits of tai chi clearly are not due to an improvement in exercise cardiac output or in peripheral extraction of oxygen by exercising muscle. What then might be the mechanism of the perceived benefits? The Minnesota Living with Heart Failure Questionnaire is a measure of the patients’ perceptions of the effects of heart failure on their lives (6). This 21-item, selfadministered questionnaire comprehensively covers physical, socioeconomic, and psychological impairments that patients often relate to their heart failure. The intervention group had a substantial lowering (improvement) of the total score, which reflects an improved reported quality of life. However, it is not clear if the improvement was due to improvements of psychological, socioeconomic, or physical impairment. A concern in the study design is that the tai chi group had roughly 24-hourly contact sessions with tai chi/health care personnel over 3 months, along with social contact with coparticipants, compared with almost no contact in the usual-care control group. Thus, one can question whether the improvements in self-reported quality of life were a result of the physical and meditative aspects of the tai chi program or the benefits of social contact with participants and health care personnel. Finally, a placebo effect could have occurred in patients who enjoyed participation in tai chi and the contact with the persons running the program. Optimally, the control group should have had a matched number of contact hours with health care personnel and social contact with other patients. Although physical aspects of the tai chi program