Tai chi harmonizes yin and yang and promotes homeostasis between body and mind. We appreciate the work by Yeh et al,1 which reported that tai chi exercise may improve quality of life, mood, and exercise self-efficacy in patients with heart failure. Objectively, the authors used a bicycle ramp protocol for determining peak oxygen uptake, 6-minute walk test for exercise capacity, the Minnesota Living With Heart Failure Questionnaire for disease-specific quality of life, the Profile of Mood states for emotional status, and the Cardiac Exercise Self-efficacy Instrument for a patient's confidence to perform certain exercise-related activities. Enhancing Yang represents the increase of cardiac performance and reflects peak oxygen uptake elevation for heart failure. Obviously, tai chi exercise processes heart failure using the yang pathway less frequently and instead reinforcing the yin pathway, which attenuates peripheral demands, stabilizes mood, and regulates autonomic nervous systems. As we know, blunted heart rate recovery at 1 second after peak exercise is associated with the severity of depression, quality of life, and autonomic nervous dysfunction in heart failure.2- 3 Accordingly, we suggest that a measurement of heart rate recovery after peak exercise could be retrospectively obtained and compared between groups at baseline and 12 weeks to confirm the roles of yin and yang for heart failure by tai chi exercise.