Tai chi is a form of exercise that combines deep breathing and relaxation with meditative, slow movements. Originally developed as a martial art in 13th-century China, tai chi is now practised around the world as a health-promoting exercise. Despite its popularity, its therapeutic value is not clear.
This randomized, assessor-blinded trial examined the therapeutic efficacy of tai chi for the management of central obesity. A total of 543 participants with central obesity were randomly assigned in a 1:1:1 ratio to:
- a control group with no exercise intervention (n = 181),
- conventional exercise consisting of aerobic exercise and strength training (EX group) (n = 181),
- a tai chi group (TC group) (n = 181). Interventions lasted 12 weeks.
Outcomes were assessed at baseline, week 12, and week 38. The primary outcome was waist circumference (WC). Secondary outcomes were body weight; body mass index; high-density lipoprotein cholesterol (HDL-C), triglyceride, and fasting plasma glucose levels; blood pressure; and incidence of remission of central obesity.
The adjusted mean difference in WC from baseline to week 12 in the control group was 0.8 cm (95% CI, -4.1 to 5.7 cm). Both intervention groups showed reductions in WC relative to control (adjusted mean differences: TC group vs. control, -1.8 cm [CI, -2.3 to -1.4 cm]; P < 0.001; EX group vs. control: -1.3 cm [CI, -1.8 to -0.9 cm]; P < 0.001); both intervention groups also showed reductions in body weight (P < 0.05) and attenuation of the decrease in HDL-C level relative to the control group. The favorable changes in WC and body weight were maintained in both the TC and EX groups, whereas the beneficial effect on HDL-C was only maintained in the TC group at week 38.
The authors concluded that Tai chi is an effective approach to reduce WC in adults with central obesity aged 50 years or older.
This is a decent trial with an odd conclusion: it is not just the Tai chi intervention but both types of exercise that yield significantly positive effects on the primary outcome measure. So, why did the authors not conclude exercise is an effective approach to reduce WC in adults with central obesity aged 50 years or older?
Could it be that such a conclusion would have meant stating the obvious?