Is Tai Chi training effective in improving cardiorespiratory fitness among healthy adults?
Date of publication of the systematic review: February 2015
Design
Systematic review summarizing results from 2 randomized controlled trials, 8 non-randomized controlled trials, 3 self-control trials and 7 cohort studies.
Participants
1868 healthy adults (age range: 45 to 75 years). The reviewers did not report gender proportion of the participants.
Intervention
Tai Chi was provided with a range of 8 weeks to 10.5 years. The frequency varied from two to seven times per week and 12 to 60 minutes per time.
Comparator
Comparison: Tai Chi training versus non-intervention.
Major Outcomes
Outcome 1: Systolic blood pressures as measured at quiet condition (mmHg);
Outcome 2: Diastolic blood pressures as measured at quiet condition (mmHg);
Outcome 3: Forced vital capacity (FVC) as measured at quiet condition (mL);
Outcome 4: Oxygen pulse as measured at quiet condition.
Settings
The trials and studies were performed in outpatient settings.
Comparison    Tai Chi training versus non-intervention
Main Results
Compared to non-intervention, Tai Chi training showed significant positive effect on cardiovascular efficiency by improving systolic blood pressure measured at quiet condition (pooled tandardized mean difference (pooled SMD): -0.93, 95% CI: -1.30 to -0.56) and diastolic blood pressures measured at quiet condition (pooled SMD: -0.54, 95% CI: -0.90 to -0.18). Besides, Tai Chi training showed significant benefits on respiratory efficiency by FVC measured at quiet condition (pooled mean difference (pooled MD): 359.16, 95% CI: 19.57 to 698.75) and showed significant effect in cardiorespiratory endurance by improving oxygen pulse (pooled SMD: 1.04, 95% CI: 0.69 to 1.39).
Comparison: Tai Chi training versus non-intervention among healthy adults
Outcomes (units) No. of studies (Total no. of participants) Mean value / No. of participants Heterogeneity test (I2) Pooled SMD/MD (95% CI) p value Overall quality of evidence*
Intervention Comparator
1 (mmHg) 9 (536) Not reported /269 Not reported /267 74% SMD: -0.93 (-1.30 to -0.56) <0.00001 High
2 (mmHg) 9 (536) Not reported /269 Not reported /267 75% SMD: -0.54 (-0.90 to -0.18) 0.003 High
3 (mL) 4 (253) Not reported /125 Not reported /128 92% MD: 359.16 (19.57 to 698.75) 0.04 Moderate
4 (NA) 3 (146) Not reported /77 Not reported /69 0% SMD: 1.04 (0.69 to 1.39) <0.00001 High
Keys: SMD = standardized mean difference; MD = mean difference; CI = confidence interval.
Comparison    Tai Chi training versus non-intervention
Main Results
Compared to non-intervention, Tai Chi training showed significant positive effect on cardiovascular efficiency by improving systolic blood pressure measured at quiet condition (pooled tandardized mean difference (pooled SMD): -0.93, 95% CI: -1.30 to -0.56) and diastolic blood pressures measured at quiet condition (pooled SMD: -0.54, 95% CI: -0.90 to -0.18). Besides, Tai Chi training showed significant benefits on respiratory efficiency by FVC measured at quiet condition (pooled mean difference (pooled MD): 359.16, 95% CI: 19.57 to 698.75) and showed significant effect in cardiorespiratory endurance by improving oxygen pulse (pooled SMD: 1.04, 95% CI: 0.69 to 1.39).
Comparison: Tai Chi training versus non-intervention among healthy adults
Outcomes (units) 1 (mmHg) 2 (mmHg) 3 (mL) 4 (NA)
No. of studies (Total no. of participants) 9 (536) 9 (536) 4 (253) 3 (146)
Mean value / No. of participants Intervention Not reported /269 Not reported /269 Not reported /125 Not reported /77
Comparator Not reported /267 Not reported /267 Not reported /128 Not reported /69
Pooled SMD/MD (95% CI) SMD: -0.93 (-1.30 to -0.56) SMD: -0.54 (-0.90 to -0.18) MD: 359.16 (19.57 to 698.75) SMD: 1.04 (0.69 to 1.39)
p value <0.00001 0.003 0.04 <0.00001
Overall quality of evidence* High High Moderate High
Keys: SMD = standardized mean difference; MD = mean difference; CI = confidence interval.
Conclusion
Benefits
Compared to non-intervention, Tai Chi training showed significant positive effect on cardiovascular efficiency by lowering systolic blood pressure and diastolic blood pressures measured at quiet condition. Besides, Tai Chi training showed significant benefits on respiratory efficiency by improving FVC and showed significant effect in enhancing cardiorespiratory endurance by improving oxygen pulse. For outcomes 1, 2 and 4, the overall quality of evidence is high. Further research is unlikely to have an important impact on our confidence in this estimate of effect. For outcome 3, the overall quality of evidence is moderate. Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
Harms
No adverse events were reported in the included trials.
Link to Original Article
http://www.ncbi.nlm.nih.gov/pubmed/25680184
The synopsis is based on the following article:
Zheng G, Li S, Huang M, Liu F, Tao J, Chen L. The effect of Tai Chi training on cardiorespiratory fitness in healthy adults: a systematic review and meta-analysis. [Review] PLoS ONE. 2015 Feb; 10(2):e0117360.


* Interpretation of quality assessment results:
• Very low: Further research is most likely to have an important impact on our confidence in this estimate of effect.
• Low: Further research is likely to have an important impact on our confidence in this estimate of effect.
• Moderate: Further research is fairly likely to have an important impact on our confidence in this estimate of effect.
• High: Further research is unlikely to have an important impact on our confidence in this estimate of effect.
• Very high: Further research is most unlikely to have an important impact on our confidence in this estimate of effect.

Details of assessment method can be found at Chung VC, Wu XY, Ziea ET, Ng BF, Wong SY, Wu JC. Assessing internal validity of clinical evidence on effectiveness of CHinese and integrative medicine: Proposed framework for a CHinese and Integrative Medicine Evidence RAting System (CHIMERAS). European Journal of Integrative Medicine. 2015 Aug 31;7(4):332-41.