The American Journal of Medicine
Volume 117, Issue 8 , Pages 611-612, 15 October 2004

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

  • Philip A. Ades, MD

      Affiliations

    • University of Vermont College of Medicine (PAA), Fletcher-Allen Health Care, Burlington, Vermont
    • Corresponding Author InformationRequests for reprints should be addressed to Philip A. Ades, MD, McClure 1, Cardiology, Fletcher-Allen, MCHV Campus, Burlington, Vermont 05401
    • ,
  • Ge Wu, PhD

      Affiliations

    • Department of Physical Therapy (GW), University of Vermont, Burlington, Vermont

Article Outline

 

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, 2, 3, 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 usual-care 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, self-administered 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 may have been responsible for the measured quality-of-life effects, that is not certain. In healthy elders and patients with mild balance disorder or a positive fall history, tai chi has been demonstrated to have benefits related to leg muscle strength (7), flexibility (8), balance and postural control (7), fear of falling (9), daily activities, and overall life quality (9, 10). These benefits should also apply to older patients with heart failure. However, these benefits are shown to be most substantial after a sufficient amount of tai chi practice, usually 40 or more sessions. In this study, subjects in the tai chi group attended an average of 20 group sessions, with additional 17 hours of home practice.

The measured improvement in 6-minute walk distance reflects an improved capacity to perform an important activity of daily living. As mentioned above, peak oxygen uptake, the best measure of aerobic fitness, did not increase after tai chi, nor were there any effects on systolic, diastolic, or mean blood pressure, or resting heart rate. The amount of tai chi practice in this study does not yet reach the normally reported 40-session threshold, so it may have minimal, if any, effect on balance. In fact, Wolf et al (10) found no change in most of the balance measures, and even a slight decrease in 12-minute walk distance in elders after a 30-session tai chi practice.

In a recent study of strength training in older women with coronary artery disease and diminished physical function, we were surprised to observe that our control group, which participated in a program of light yoga and breathing exercises, experienced an increase in leg extensor strength over a 4-month period (11). Since we had previously found, in a study of healthy elders, that increased strength translates to improved walking endurance (12), it is conceivable that in the present study tai chi resulted in increased leg strength in these highly disabled patients with heart failure. The increased leg strength might have been attributed to the Yang-style tai chi adopted in the study. The Yang style, which demands constant knee flexion, wide stance width, and a steady slow speed, is a good exercise for strengthening leg muscles. Alternatively, the increased leg strength might also be attributed to the increase in non–tai chi–related physical activity level. About 93% of tai chi group subjects had regular physical activities, as compared with 85% in the control group. The intensity of physical activity was not reported and compared between groups.

The improvement in BNP after participation in tai chi was the most intriguing aspect of this study. BNP, which is stored primarily in ventricular myocardium and is released in response to increases in ventricular filling pressures associated with myocyte stretch (13), is a powerful predictor of prognosis in heart failure (14). Other factors associated with BNP secretion include hypoxia and oxytocin (15). Although measures of blood pressure and heart rate were unaffected by the tai chi program, intracardiac hemodynamic measures, or post-training echocardiography, were not performed. Whether tai chi favorably alters left ventricular filling pressures in heart failure remains to be studied. Furthermore, whether stress reduction and other psychological aspects of the tai chi program play a role is simply not known.

Is tai chi indicated specifically for older patients with heart failure or might it have more general benefits for all older persons with chronic disease, to treat or prevent disability? As mentioned by the authors, a larger-scale investigation, with an age-matched comparison group that adjusts for group social effect, along with measures of left ventricular hemodynamics, is warranted.

Back to Article Outline

References 

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PII: S0002-9343(04)00496-6

doi:10.1016/j.amjmed.2004.08.001

The American Journal of Medicine
Volume 117, Issue 8 , Pages 611-612, 15 October 2004

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