ORIGINAL ARTICLE
Heart, Lung and Circulation (2014) 23, 347–352 1443-9506/04/$36.00 http://dx.doi.org/10.1016/j.hlc.2013.10.057
The Effect of Tai Chi on Chronic Obstructive Pulmonary Disease: A Pilot Randomised Study of Lung Function, Exercise Capacity and Diaphragm Strength Ruichao Niu 1*, Ruoxi He 1, Bai-ling Luo, Chengping Hu Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan Province 410008, PR China Received 17 June 2013; received in revised form 26 September 2013; accepted 8 October 2013; online published-ahead-of-print 17 October 2013
Background
Although the benefits of exercise on the health of patients with chronic obstructive pulmonary disease (COPD) have been widely reported, the effect of Tai Chi as an alternative exercise has not been thoroughly evaluated in patients with COPD. This study reported a randomised controlled trial, which investigated the effects of Tai Chi on lung function, exercise capacity, and diaphragm strength in patients with COPD.
Trial design
Single blind randomised controlled study.
Setting
Department of Respiratory Medicine, Xiangya Hospital, Central South University.
Methods
Forty patients with COPD were randomised into either a control group or Tai Chi intervention group. Participants in the control group received only routine care, while participants in the Tai Chi group received routine care and completed a six-month Tai Chi exercise program.
Outcomes
Lung function parameters, blood gas parameters, 6-min walking distance (6MWD), and diaphragm strength parameters.
Results
Lung function parameters (FEV1: 1.43 0.08 and FEV1 (%) predicted: 47.6 4.76), 6MWD (476 15) and diaphragm strength parameters (TwPes: 1.17 0.07, TwPga: 1.12 0.06, and TwPdi: 1.81 0.09) were found to be significantly increased in participants who successfully completed the six-month Tai Chi program compared to participants in the control group who only received routine care (p < 0.05). These parameters were also found to be significantly increased in participants who completed the Tai Chi exercise program compared to the baseline (p < 0.05). In contrast, no significant differences in PaO2 and PaCO2 were observed in participants before or after completing a Tai Chi program or between Tai Chi group and control group (p > 0.05).
Conclusions
Tai Chi enhances lung function, exercise capacity, and diaphragm strength. However, this is only preliminary research data and a larger trial is needed for more detailed results.
Keywords
Chronic obstructive pulmonary disease Tai Chi Diaphragm strength Lung function 6MWD
Introduction Chronic obstructive pulmonary disease (COPD) is a major cause of mortality and morbidity worldwide. COPD has
become the third leading cause of death in China [1]. Despite improvements in pharmacologic and surgical treatments, many patients still suffer from dyspnoea and disabilities in daily life. At present, the primary goals in COPD
*Corresponding author. Tel.: +86 731 84327105; fax: +86 731 85792836., Emails: [email protected], [email protected] 1
These authors contributed equally.
© 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier Inc. All rights reserved.
348
management are to alleviate symptoms, slow down the deterioration of lung function, and minimise the disabilities of patients [2]. In clinical practice, pulmonary rehabilitation programs are widely accepted as effective non-pharmacotherapies for COPD [3]. However, only a very small percentage of eligible patients actually participated in pulmonary rehabilitation programs [4]. Even for patients who completed these programs, maintaining a high level of activity is problematic, and clinical benefits decline dramatically after one year [5]. Exercise is a major part of pulmonary rehabilitation programs [6]. However, there is an ongoing debate regarding what the optimal type, intensity, and duration of exercise for pulmonary rehabilitation should be [6,7]. Therefore, developing an exercise program that is widely available, easily implemented, low-cost, and able to promote self-efficacy of exercise among patients with COPD is very important. The characteristics of a Tai Chi program make it the perfect candidate [8]. Tai Chi (also known as Tai Chi chuan or taijiquan) is a mind–body exercise developed in ancient China characterised by mild to moderate aerobic activity and lower-extremity as well as unsupported upper-extremity muscle strength training [9]. The Tai Chi program consists of slow, continuous movements and incorporates elements of balance and relaxation [8]. Studies have investigated Tai Chi as an intervention for a variety of health concerns, including chronic cardiovascular diseases [10], cardiorespiratory fitness [11], and musculoskeletal diseases [12]. In particular, the Tai Chi program combines breathing and respiratory muscle training with stress management, which are also essential aspects of COPD management [13]. Thus, Tai Chi may be a suitable exercise used for pulmonary rehabilitation of patients with COPD [14]. We hypothesise that participating in a Tai Chi program can help improve lung function and exercise capacity through increasing diaphragm strength in COPD patients. Although evidence for the physiological benefits of Tai Chi on COPD is emerging, these studies convey inconsistent results due to wide variations in Tai Chi programs and different measurements used to evaluate the outcomes [9– 15]. The primary measurements used in these studies include 6-min walking distance (6MWD) and dyspnoea [15]. Few studies have evaluated the benefits of Tai Chi on lung function and diaphragm strength in people with COPD [9]. In this study, a randomised controlled trial was conducted to evaluate the effect of a Tai Chi program on lung function, exercise capacity, and diaphragm strength in patients with COPD.
Materials and Methods Trial Design This is a single blind randomised controlled trial. The participants were assigned randomly to two groups: the control group and Tai Chi group with 1:1 allocation ratio.
Participants A participant’s eligibility for inclusion in the trial was determined by two senior physicians who were involved neither
R. Niu et al.
in the therapy nor in data analysis of the study. A total of 52 COPD patients were recruited from January 2011 to June 2011 from the outpatient clinics of the Department of Respiratory Medicine, Xiangya Hospital, Central South University. The subjects were selected based on the following criteria: (1) moderate to severe COPD diagnosed clinically; (2) FEV1 < 65% of predicted, and ratio of FEV1 to forced vital capacity 0.05).
Statistically Significant Improvements in Lung Function, Exercise Capacity, and Diaphragm Strength were Observed in Participants after Completion of the Tai Chi Program As shown in Table 3, statistically significant increases in lung function parameters [FEV1 and FEV1 (%) predicted], 6MWD,
Data were presented as mean and standard error (SEM). Differences in parameter values before and after the trial in each group were compared using paired t-tests. Differences between two groups were analysed using unpaired t-tests. p < 0.05 was considered statistically significant.
Assessed for eligibility (n=52) Excluded (n=12) Not meeting inclusion criteria (n=8) Declined to participate (n=2) other reasons (n=2)
Ethics The study protocol was approved by the university ethics committee (Central South University Review Board), and the studies were carried out in accordance with the Declaration of Helsinki.
Results Demographic Data and Baseline Values The study was conducted from January 2011 to February 2012. The study concluded six months after the participants
Randomised (n=40)
Allocated to control (n=20)
Allocated to Tai Chi (n=20)
Lost to follow-up (died) (n=1)
Lost to follow-up (n=0)
Analysis (n=19)
Analysis (n=20)
Excluded from analysis (n=1) (patient died before outcome measures)
Excluded from analysis (n=0)
Figure 1 Flow diagram of the progress.
350
R. Niu et al.
Table 1 Demographic Data and Baseline Characteristics (Mean SEM). Control Subjects (n) Gender (M/F)
20 18/2
95% CI
Tai Chi
95% CI
p Value
20 19/1
Age (years)
61.3 2.89
56.5–62.9
0.863
Height (cm)
159 6.9
154.2–163.8
161 6.3
156.6–165.4
0.912
Weight (kg)
54 1.7
52–56
56 2.6
53.6–58.4
0.765
FEV1
1.18 0.09
0.46–1.90
1.21 0.10
0.39–2.03
0.898
FEV1 (%) predicted
43.7 5.16
37.0–50.4
41.9 5.50
34.4–49.4
0.853
PaO2 (mmHg)
69 1.9
71 2.3
68.6–73.4
0.774
PaCO2 (mmHg) 6MWD (m)
43 1.5 422 20.0
39.6–44.4 421.4–440.6
0.982 0.687
58.1–64.5
67–71 41–45 413.7–430.3
59.7 2.76
42 1.7 431 22.8
FEV1: forced expiratory volume in one second; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; 6MWD: 6-min walking distance.
intensity was conducted for each COPD patient. The Tai Chi program significantly increased lung function, exercise capacity, and diaphragm strength in patients with COPD. This study provided primary evidence supporting Tai Chi as an alternative non-pharmacotherapy of COPD. It has been revealed that only a very small percentage of patients with moderate to severe COPD actually underwent a pulmonary rehabilitation program [4]. In contrast, Tai Chi is an exercise that has usually received wide social support. A high adherence rate with Tai Chi exercise was previously reported [17]. This study also revealed a high adherence rate in the Tai Chi group. In addition, conventional pulmonary rehabilitation involves exercise equipment, while Tai Chi does not require special equipment or a special workout room and is very cost effective [18]. Therefore, Tai Chi could make effective exercise more accessible for a greater number of people with COPD, especially for those living in rural areas. Moreover, achieving a moderate to high exercise intensity is the goal of pulmonary rehabilitation. However, any moderate to high intensity exercise may not always be suitable for COPD patients with co-morbidities, particularly with
and diaphragm strength parameters (TwPes, TwPga, and TwPdi) were observed in participants after completion of the six-month Tai Chi program (p < 0.05) in the Tai Chi group. In contrast, no statistically significant changes in PaO2 and PaCO2 were observed in participants after completion of the Tai Chi program (p > 0.05) in the Tai Chi group. In addition, no statistically significant differences in lung function, exercise capacity, and diaphragm strength were observed in participants with routine care before and after trial.
Discussion Recent studies revealed that Tai Chi exercise could improve exercise capacity, dyspnoea, quality of life, and lung function compared with general exercise or routine care in COPD patients [9,13–15]. However, no conclusive data were reported and these studies did not evaluate the effect of Tai Chi on diaphragm strength and blood gas parameters. In this study, a six-month Tai Chi program with adjustable
Table 2 Comparison of Parameters Between Control and Tai Chi Group After (Post) Trial (Mean SEM). Control (n = 19)
95% CI
Tai Chi (n = 20)
95% CI
p Value
1.18 0.09 42.6 5.46
0.38–1.98 35.4–49.8
1.43 0.08 47.6 4.76
0.75–2.11 41.5–53.7
0.038 0.046
PaO2 (mmHg)
71 2.04
68.9–73.1
73 2.53
70.4–75.6
0.624
PaCO2 mmHg)
42 1.47
40.1–43.9
40 2.04
37.2–42.8
0.322 0.031
FEV1 FEV1 (%) predicted
6MWD (m)
416 22.5
406.6–425.4
476 15.0
470–482
TwPes (kPa)
0.89 0.08
0.23–1.55
1.17 0.07
0.49–1.85
TwPga (kPa)
1.0 0.09
1.80 to
1.12 0.06
1.63 to
TwPdi (kPa)
1.51 0.11
0.55–2.47
1.81 0.09
0.99–2.63
0.2
0.002 0.61
0.047 0.028
FEV1: forced expiratory volume in 1 s; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; 6MWD: 6-min walking distance. TwPes: twitch oesophageal pressure; TwPga: twitch gastric pressure; TwPdi: twitch transdiaphragmatic pressure.
351
The Effect of Tai Chi in COPD
Table 3 Comparison of Parameters Before (Pre) and After (Post) Trial in Tai Chi Group (Mean SEM). Pre-trial (n = 20)
95% CI
Post-trial (n = 20)
95% CI
p Value
1.21 0.10 41.9 5.50
0.39–2.03 34.4–49.4
1.43 0.08 47.6 4.76
0.75–2.11 41.5–53.7
0.046 0.031
PaO2 (mmHg)
71 2.3
68.6–73.4
73 2.53
70.4–75.6
0.679
PaCO2 (mmHg)
42 1.7
39.6–44.4
40 2.04
37.2–42.8
0.389 0.044
FEV1 FEV1 (%) predicted
6MWD (m)
431 22.8
421.4–440.6
476 15.0
470–482
TwPes (kPa)
1.00 0.07
0.40–1.40
1.17 0.07
0.49–1.85
TwPga (kPa)
1.01 0.08
1.55 to
1.12 0.06
1.63 to
TwPdi (kPa)
1.57 0.44
2.17–5.31
1.81 0.09
0.99–2.63
0.47
0.016 0.61
0.048 0.032
FEV1: forced expiratory volume in one second; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; 6MWD: 6-min walking distance. TwPes: twitch oesophageal pressure; TwPga: twitch gastric pressure; TwPdi: twitch transdiaphragmatic pressure.
cardiovascular diseases. In contrast, Tai Chi is a mild to moderate intensity exercise. In this study, the intensity of the Tai Chi program was tailored to the individual’s limiting factors for exercise. Therefore, Tai Chi might be useful for combating the increasing prevalence of COPD and suitable for COPD patients with co-morbidities. Tai Chi consists of a series of slow movements and deep breathing. The deep breathing is believed to improve lung function, but requires further evidence. In this study, Tai Chi exercise significantly increased the diaphragm strength, which parallels the increases in lung function parameters. This suggests that Tai Chi may improve breathing through increasing diaphragm strength. Cahalin et al’s. [19] study has shown that diaphragmatic breathing has potential beneficial effects for pulmonary functions, but adverse effects, such as decreased efficacy of breathing and increased dyspnoea, may also exist. However, in this study, we did not observe serious adverse events, and an increase in PaO2 and decrease in PaCO2 were observed although this was not significant. This suggests that the Tai Chi program in this study could reduce the adverse effects of diaphragmatic breathing though further studies are required to explain how this works. Previous studies investigated the effect of Tai Chi on exercise capacity, but showed inconsistent observations. For example, Yeh et al. study showed nonsignificant trends of Tai Chi towards improvement of 6-min walk distance [13], while Chan et al. study indicated that Tai Chi exercise increased 6-min walk distance [15]. In this study, the six-month Tai Chi trial was able to maintain patients’ exercise capacity levels without significant decline. In general, moderate to severe COPD patients showed progressive loss of lung function and exercise capacity [20]. However, routine care can also help slow down disease progression and postpone disability in COPD patients. Therefore, it is difficult to conclude whether Tai Chi plays an independent role from routine care or shares a coordinated effect with routine care because this study lacks a group that only received the Tai Chi program without routine care.
Tai Chi is safe, accessible, and enjoyable, has a high adherence rate [21], and has been reported to play a role in chronic cardiovascular diseases [10], cardiorespiratory fitness [11], and musculoskeletal diseases [12]. Therefore, Tai Chi may have a wide generalisability for chronic diseases. There are several limitations to this study. For example, conventional medicine was used, and there was not a Tai Chi alone group. Therefore, the outcomes may be affected by the differences in patients’ sensitivity to medicine. Although a Tai Chi alone group may more clearly prove its usefulness as an independent therapy option, this may not be practicable for moderate to severe COPD patients. This study was also limited by its small sample size and the lack of a mechanism study. However, this small pilot study observed statistical differences in lung function improvement, which may be mainly caused by the enhancement of diaphragm strength although further studies are required. Without any doubt, other objective outcome measurements, such as survival, cognitive function, immune function, and molecular changes could enhance our understanding of the mechanism of Tai Chi exercise. In addition, this trial may have potential biases because the subjects may be aware of the study design through communication with the therapists. In conclusion, this study provides preliminary data to support Tai Chi as a meditative exercise that may be a therapeutic option for patients with COPD. Tai Chi may be a safe adjunct or alternative to routine care in patients with COPD. However, this is a pilot study and a larger trial is needed to obtain more detailed results. Importantly, a further study is required to clarify whether the change in 6-min walk distance exceeds the minimum, clinical, important difference, whether the small changes in FEV1 really impact the life of patients with COPD, and whether this could translate into improved quality of life.
Funding Resource This is a self-funded study which did not receive any external funding.
352
R. Niu et al.
Conflict of Interest All authors declared no conflict of interest.
[11] [12]
References [1] Yang G, Wang Y, Zeng Y, Gao GF, Liang X, Zhou M, et al. Rapid health transition in China, 1990–2010: findings from the Global Burden of Disease Study 2010. Lancet 2013;381:1987–2015. [2] Russell R, Anzueto A, Weisman I. Optimizing management of chronic obstructive pulmonary disease in the upcoming decade. Int J Chron Obstruct Pulmon Dis 2011;6:47–61. [3] Leung RWM, Alison JA, McKeough ZJ, Peters MJ. Contemporary clinical. Trials 2011;32:267–72. [4] Cote CG, Celli BR. Pulmonary rehabilitation and the BODE index in COPD. Eur Respir J 2005;26:630–6. [5] Ries AL, Kaplan RM, Myers R, Prewitt LM. Maintenance after pulmonary rehabilitation in chronic lung disease: a randomized trial. Am J Respir Crit Care Med 2003;167:880–8. [6] Lacasse Y, Goldstein R, Lasserson TJ, Martin S. Pulmonary rehabilitation for chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2006;4:CD003793. [7] Lacasse Y, Martin S, Lasserson TJ, Goldstein RS. Meta-analysis of respiratory rehabilitation in chronic obstructive pulmonary disease: a Cochrane systematic review. Eura Medicophys 2007;43:475–85. [8] Cheng M. Master Cheng’s thirteen chapters on T’ai Chi Chuan. New York: Sweet Chi Press; 1982. [9] Yan J, Guo Y, Yao H, Pan L. Effects of Tai Chi in patients with chronic obstructive pulmonary disease: preliminary evidence. PLoS ONE 2013;8: e61806. [10] Yeh GY, Wood MJ, Lorell BH, Stevenson LW, Eisenberg DM, Wayne PM, et al. Effects of tai chi mind-body movement therapy on functional
[13]
[14]
[15]
[16] [17]
[18]
[19]
[20]
[21]
status and exercise capacity in patients with chronic heart failure: a randomized controlled trial. Am J Med 2004;117:541–658. Lan C, Lai JS, Chen SY, Wong MK. 12-Month Tai Chi training in the elderly: its effect on health fitness. Med Sci Sports Exerc 1998;30:345–51. Lan C, Lai JS, Chen SY, Wong MK. Tai Chi Chuan to improve muscular strength and endurance in elderly individuals: a pilot study. Arch Phys Med Rehabil 2000;81:604–7. Yeh GY, Roberts DH, Wayne PM, Davis RB, Quilty MT, Phillips RS. Tai Chi exercise for patients with chronic pulmonary obstructive disease: a pilot study. Respir Care 2010;55:1475–82. Chan AW, Lee A, Suen LK, Tam WW. Effectiveness of a Tai Chi Qigong program in promoting HR-QoL and perceived social support in COPD clients. Qual Life Res 2010;19:653–64. Chan AW, Lee A, Suen LK, Tam WW. Tai Chi Qigong improves lung functions (sic) and activity tolerance in COPD clients: a single blind, randomized controlled trial. Complement Ther Med 2011;19:3–11. Chetta A, Pisi G, Aiello M, Tzani P, Olivieri D. The walking capacity assessment in the respiratory patient. Respiration 2009;77:361–7. Brismee JM, Paige RL, Chyu MC, Boatright JD, Hagar JM, McCaleb JA, et al. Group and home-based Tai Chi in elderly subjects with knee osteoarthritis: a randomized controlled trial. Clin Rehabil 2007;21:99–111. Church J, Goodall S, Norman R, Haas M. An economic evaluation of community and residential aged care falls prevention strategies in NSW. N S W Public Health Bull 2011;22:60–8. Cahalin LP, Braga M, Matsuo Y, Hernandez E. Efficacy of diaphragmatic breathing in persons with chronic obstructive pulmonary disease: a review of the literature. J Cardpulm Rehabil 2002;22:7–21. Lee SJ, Lee SH, Kim YE, Cho YJ, Jeong YY, Kim HC, et al. Clinical features according to the frequency of acute exacerbatiOn in COPD. Tuberc Respir Dis (Seoul) 2012;72:367–73. Sandlund E, Norlander S, Torsten A. The effects of Tai Chi Chuan relaxation and exercise on stress responses and well-being: an overview of research. Int J Stress Manag 2000;7:139–49.
Heart, Lung and Circulation (2014) 23, 347–352 1443-9506/04/$36.00 http://dx.doi.org/10.1016/j.hlc.2013.10.057
The Effect of Tai Chi on Chronic Obstructive Pulmonary Disease: A Pilot Randomised Study of Lung Function, Exercise Capacity and Diaphragm Strength Ruichao Niu 1*, Ruoxi He 1, Bai-ling Luo, Chengping Hu Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan Province 410008, PR China Received 17 June 2013; received in revised form 26 September 2013; accepted 8 October 2013; online published-ahead-of-print 17 October 2013
Background
Although the benefits of exercise on the health of patients with chronic obstructive pulmonary disease (COPD) have been widely reported, the effect of Tai Chi as an alternative exercise has not been thoroughly evaluated in patients with COPD. This study reported a randomised controlled trial, which investigated the effects of Tai Chi on lung function, exercise capacity, and diaphragm strength in patients with COPD.
Trial design
Single blind randomised controlled study.
Setting
Department of Respiratory Medicine, Xiangya Hospital, Central South University.
Methods
Forty patients with COPD were randomised into either a control group or Tai Chi intervention group. Participants in the control group received only routine care, while participants in the Tai Chi group received routine care and completed a six-month Tai Chi exercise program.
Outcomes
Lung function parameters, blood gas parameters, 6-min walking distance (6MWD), and diaphragm strength parameters.
Results
Lung function parameters (FEV1: 1.43 0.08 and FEV1 (%) predicted: 47.6 4.76), 6MWD (476 15) and diaphragm strength parameters (TwPes: 1.17 0.07, TwPga: 1.12 0.06, and TwPdi: 1.81 0.09) were found to be significantly increased in participants who successfully completed the six-month Tai Chi program compared to participants in the control group who only received routine care (p < 0.05). These parameters were also found to be significantly increased in participants who completed the Tai Chi exercise program compared to the baseline (p < 0.05). In contrast, no significant differences in PaO2 and PaCO2 were observed in participants before or after completing a Tai Chi program or between Tai Chi group and control group (p > 0.05).
Conclusions
Tai Chi enhances lung function, exercise capacity, and diaphragm strength. However, this is only preliminary research data and a larger trial is needed for more detailed results.
Keywords
Chronic obstructive pulmonary disease Tai Chi Diaphragm strength Lung function 6MWD
Introduction Chronic obstructive pulmonary disease (COPD) is a major cause of mortality and morbidity worldwide. COPD has
become the third leading cause of death in China [1]. Despite improvements in pharmacologic and surgical treatments, many patients still suffer from dyspnoea and disabilities in daily life. At present, the primary goals in COPD
*Corresponding author. Tel.: +86 731 84327105; fax: +86 731 85792836., Emails: [email protected], [email protected] 1
These authors contributed equally.
© 2013 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier Inc. All rights reserved.
348
management are to alleviate symptoms, slow down the deterioration of lung function, and minimise the disabilities of patients [2]. In clinical practice, pulmonary rehabilitation programs are widely accepted as effective non-pharmacotherapies for COPD [3]. However, only a very small percentage of eligible patients actually participated in pulmonary rehabilitation programs [4]. Even for patients who completed these programs, maintaining a high level of activity is problematic, and clinical benefits decline dramatically after one year [5]. Exercise is a major part of pulmonary rehabilitation programs [6]. However, there is an ongoing debate regarding what the optimal type, intensity, and duration of exercise for pulmonary rehabilitation should be [6,7]. Therefore, developing an exercise program that is widely available, easily implemented, low-cost, and able to promote self-efficacy of exercise among patients with COPD is very important. The characteristics of a Tai Chi program make it the perfect candidate [8]. Tai Chi (also known as Tai Chi chuan or taijiquan) is a mind–body exercise developed in ancient China characterised by mild to moderate aerobic activity and lower-extremity as well as unsupported upper-extremity muscle strength training [9]. The Tai Chi program consists of slow, continuous movements and incorporates elements of balance and relaxation [8]. Studies have investigated Tai Chi as an intervention for a variety of health concerns, including chronic cardiovascular diseases [10], cardiorespiratory fitness [11], and musculoskeletal diseases [12]. In particular, the Tai Chi program combines breathing and respiratory muscle training with stress management, which are also essential aspects of COPD management [13]. Thus, Tai Chi may be a suitable exercise used for pulmonary rehabilitation of patients with COPD [14]. We hypothesise that participating in a Tai Chi program can help improve lung function and exercise capacity through increasing diaphragm strength in COPD patients. Although evidence for the physiological benefits of Tai Chi on COPD is emerging, these studies convey inconsistent results due to wide variations in Tai Chi programs and different measurements used to evaluate the outcomes [9– 15]. The primary measurements used in these studies include 6-min walking distance (6MWD) and dyspnoea [15]. Few studies have evaluated the benefits of Tai Chi on lung function and diaphragm strength in people with COPD [9]. In this study, a randomised controlled trial was conducted to evaluate the effect of a Tai Chi program on lung function, exercise capacity, and diaphragm strength in patients with COPD.
Materials and Methods Trial Design This is a single blind randomised controlled trial. The participants were assigned randomly to two groups: the control group and Tai Chi group with 1:1 allocation ratio.
Participants A participant’s eligibility for inclusion in the trial was determined by two senior physicians who were involved neither
R. Niu et al.
in the therapy nor in data analysis of the study. A total of 52 COPD patients were recruited from January 2011 to June 2011 from the outpatient clinics of the Department of Respiratory Medicine, Xiangya Hospital, Central South University. The subjects were selected based on the following criteria: (1) moderate to severe COPD diagnosed clinically; (2) FEV1 < 65% of predicted, and ratio of FEV1 to forced vital capacity 0.05).
Statistically Significant Improvements in Lung Function, Exercise Capacity, and Diaphragm Strength were Observed in Participants after Completion of the Tai Chi Program As shown in Table 3, statistically significant increases in lung function parameters [FEV1 and FEV1 (%) predicted], 6MWD,
Data were presented as mean and standard error (SEM). Differences in parameter values before and after the trial in each group were compared using paired t-tests. Differences between two groups were analysed using unpaired t-tests. p < 0.05 was considered statistically significant.
Assessed for eligibility (n=52) Excluded (n=12) Not meeting inclusion criteria (n=8) Declined to participate (n=2) other reasons (n=2)
Ethics The study protocol was approved by the university ethics committee (Central South University Review Board), and the studies were carried out in accordance with the Declaration of Helsinki.
Results Demographic Data and Baseline Values The study was conducted from January 2011 to February 2012. The study concluded six months after the participants
Randomised (n=40)
Allocated to control (n=20)
Allocated to Tai Chi (n=20)
Lost to follow-up (died) (n=1)
Lost to follow-up (n=0)
Analysis (n=19)
Analysis (n=20)
Excluded from analysis (n=1) (patient died before outcome measures)
Excluded from analysis (n=0)
Figure 1 Flow diagram of the progress.
350
R. Niu et al.
Table 1 Demographic Data and Baseline Characteristics (Mean SEM). Control Subjects (n) Gender (M/F)
20 18/2
95% CI
Tai Chi
95% CI
p Value
20 19/1
Age (years)
61.3 2.89
56.5–62.9
0.863
Height (cm)
159 6.9
154.2–163.8
161 6.3
156.6–165.4
0.912
Weight (kg)
54 1.7
52–56
56 2.6
53.6–58.4
0.765
FEV1
1.18 0.09
0.46–1.90
1.21 0.10
0.39–2.03
0.898
FEV1 (%) predicted
43.7 5.16
37.0–50.4
41.9 5.50
34.4–49.4
0.853
PaO2 (mmHg)
69 1.9
71 2.3
68.6–73.4
0.774
PaCO2 (mmHg) 6MWD (m)
43 1.5 422 20.0
39.6–44.4 421.4–440.6
0.982 0.687
58.1–64.5
67–71 41–45 413.7–430.3
59.7 2.76
42 1.7 431 22.8
FEV1: forced expiratory volume in one second; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; 6MWD: 6-min walking distance.
intensity was conducted for each COPD patient. The Tai Chi program significantly increased lung function, exercise capacity, and diaphragm strength in patients with COPD. This study provided primary evidence supporting Tai Chi as an alternative non-pharmacotherapy of COPD. It has been revealed that only a very small percentage of patients with moderate to severe COPD actually underwent a pulmonary rehabilitation program [4]. In contrast, Tai Chi is an exercise that has usually received wide social support. A high adherence rate with Tai Chi exercise was previously reported [17]. This study also revealed a high adherence rate in the Tai Chi group. In addition, conventional pulmonary rehabilitation involves exercise equipment, while Tai Chi does not require special equipment or a special workout room and is very cost effective [18]. Therefore, Tai Chi could make effective exercise more accessible for a greater number of people with COPD, especially for those living in rural areas. Moreover, achieving a moderate to high exercise intensity is the goal of pulmonary rehabilitation. However, any moderate to high intensity exercise may not always be suitable for COPD patients with co-morbidities, particularly with
and diaphragm strength parameters (TwPes, TwPga, and TwPdi) were observed in participants after completion of the six-month Tai Chi program (p < 0.05) in the Tai Chi group. In contrast, no statistically significant changes in PaO2 and PaCO2 were observed in participants after completion of the Tai Chi program (p > 0.05) in the Tai Chi group. In addition, no statistically significant differences in lung function, exercise capacity, and diaphragm strength were observed in participants with routine care before and after trial.
Discussion Recent studies revealed that Tai Chi exercise could improve exercise capacity, dyspnoea, quality of life, and lung function compared with general exercise or routine care in COPD patients [9,13–15]. However, no conclusive data were reported and these studies did not evaluate the effect of Tai Chi on diaphragm strength and blood gas parameters. In this study, a six-month Tai Chi program with adjustable
Table 2 Comparison of Parameters Between Control and Tai Chi Group After (Post) Trial (Mean SEM). Control (n = 19)
95% CI
Tai Chi (n = 20)
95% CI
p Value
1.18 0.09 42.6 5.46
0.38–1.98 35.4–49.8
1.43 0.08 47.6 4.76
0.75–2.11 41.5–53.7
0.038 0.046
PaO2 (mmHg)
71 2.04
68.9–73.1
73 2.53
70.4–75.6
0.624
PaCO2 mmHg)
42 1.47
40.1–43.9
40 2.04
37.2–42.8
0.322 0.031
FEV1 FEV1 (%) predicted
6MWD (m)
416 22.5
406.6–425.4
476 15.0
470–482
TwPes (kPa)
0.89 0.08
0.23–1.55
1.17 0.07
0.49–1.85
TwPga (kPa)
1.0 0.09
1.80 to
1.12 0.06
1.63 to
TwPdi (kPa)
1.51 0.11
0.55–2.47
1.81 0.09
0.99–2.63
0.2
0.002 0.61
0.047 0.028
FEV1: forced expiratory volume in 1 s; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; 6MWD: 6-min walking distance. TwPes: twitch oesophageal pressure; TwPga: twitch gastric pressure; TwPdi: twitch transdiaphragmatic pressure.
351
The Effect of Tai Chi in COPD
Table 3 Comparison of Parameters Before (Pre) and After (Post) Trial in Tai Chi Group (Mean SEM). Pre-trial (n = 20)
95% CI
Post-trial (n = 20)
95% CI
p Value
1.21 0.10 41.9 5.50
0.39–2.03 34.4–49.4
1.43 0.08 47.6 4.76
0.75–2.11 41.5–53.7
0.046 0.031
PaO2 (mmHg)
71 2.3
68.6–73.4
73 2.53
70.4–75.6
0.679
PaCO2 (mmHg)
42 1.7
39.6–44.4
40 2.04
37.2–42.8
0.389 0.044
FEV1 FEV1 (%) predicted
6MWD (m)
431 22.8
421.4–440.6
476 15.0
470–482
TwPes (kPa)
1.00 0.07
0.40–1.40
1.17 0.07
0.49–1.85
TwPga (kPa)
1.01 0.08
1.55 to
1.12 0.06
1.63 to
TwPdi (kPa)
1.57 0.44
2.17–5.31
1.81 0.09
0.99–2.63
0.47
0.016 0.61
0.048 0.032
FEV1: forced expiratory volume in one second; PaO2: partial pressure of oxygen; PaCO2: partial pressure of carbon dioxide; 6MWD: 6-min walking distance. TwPes: twitch oesophageal pressure; TwPga: twitch gastric pressure; TwPdi: twitch transdiaphragmatic pressure.
cardiovascular diseases. In contrast, Tai Chi is a mild to moderate intensity exercise. In this study, the intensity of the Tai Chi program was tailored to the individual’s limiting factors for exercise. Therefore, Tai Chi might be useful for combating the increasing prevalence of COPD and suitable for COPD patients with co-morbidities. Tai Chi consists of a series of slow movements and deep breathing. The deep breathing is believed to improve lung function, but requires further evidence. In this study, Tai Chi exercise significantly increased the diaphragm strength, which parallels the increases in lung function parameters. This suggests that Tai Chi may improve breathing through increasing diaphragm strength. Cahalin et al’s. [19] study has shown that diaphragmatic breathing has potential beneficial effects for pulmonary functions, but adverse effects, such as decreased efficacy of breathing and increased dyspnoea, may also exist. However, in this study, we did not observe serious adverse events, and an increase in PaO2 and decrease in PaCO2 were observed although this was not significant. This suggests that the Tai Chi program in this study could reduce the adverse effects of diaphragmatic breathing though further studies are required to explain how this works. Previous studies investigated the effect of Tai Chi on exercise capacity, but showed inconsistent observations. For example, Yeh et al. study showed nonsignificant trends of Tai Chi towards improvement of 6-min walk distance [13], while Chan et al. study indicated that Tai Chi exercise increased 6-min walk distance [15]. In this study, the six-month Tai Chi trial was able to maintain patients’ exercise capacity levels without significant decline. In general, moderate to severe COPD patients showed progressive loss of lung function and exercise capacity [20]. However, routine care can also help slow down disease progression and postpone disability in COPD patients. Therefore, it is difficult to conclude whether Tai Chi plays an independent role from routine care or shares a coordinated effect with routine care because this study lacks a group that only received the Tai Chi program without routine care.
Tai Chi is safe, accessible, and enjoyable, has a high adherence rate [21], and has been reported to play a role in chronic cardiovascular diseases [10], cardiorespiratory fitness [11], and musculoskeletal diseases [12]. Therefore, Tai Chi may have a wide generalisability for chronic diseases. There are several limitations to this study. For example, conventional medicine was used, and there was not a Tai Chi alone group. Therefore, the outcomes may be affected by the differences in patients’ sensitivity to medicine. Although a Tai Chi alone group may more clearly prove its usefulness as an independent therapy option, this may not be practicable for moderate to severe COPD patients. This study was also limited by its small sample size and the lack of a mechanism study. However, this small pilot study observed statistical differences in lung function improvement, which may be mainly caused by the enhancement of diaphragm strength although further studies are required. Without any doubt, other objective outcome measurements, such as survival, cognitive function, immune function, and molecular changes could enhance our understanding of the mechanism of Tai Chi exercise. In addition, this trial may have potential biases because the subjects may be aware of the study design through communication with the therapists. In conclusion, this study provides preliminary data to support Tai Chi as a meditative exercise that may be a therapeutic option for patients with COPD. Tai Chi may be a safe adjunct or alternative to routine care in patients with COPD. However, this is a pilot study and a larger trial is needed to obtain more detailed results. Importantly, a further study is required to clarify whether the change in 6-min walk distance exceeds the minimum, clinical, important difference, whether the small changes in FEV1 really impact the life of patients with COPD, and whether this could translate into improved quality of life.
Funding Resource This is a self-funded study which did not receive any external funding.
352
R. Niu et al.
Conflict of Interest All authors declared no conflict of interest.
[11] [12]
References [1] Yang G, Wang Y, Zeng Y, Gao GF, Liang X, Zhou M, et al. Rapid health transition in China, 1990–2010: findings from the Global Burden of Disease Study 2010. Lancet 2013;381:1987–2015. [2] Russell R, Anzueto A, Weisman I. Optimizing management of chronic obstructive pulmonary disease in the upcoming decade. Int J Chron Obstruct Pulmon Dis 2011;6:47–61. [3] Leung RWM, Alison JA, McKeough ZJ, Peters MJ. Contemporary clinical. Trials 2011;32:267–72. [4] Cote CG, Celli BR. Pulmonary rehabilitation and the BODE index in COPD. Eur Respir J 2005;26:630–6. [5] Ries AL, Kaplan RM, Myers R, Prewitt LM. Maintenance after pulmonary rehabilitation in chronic lung disease: a randomized trial. Am J Respir Crit Care Med 2003;167:880–8. [6] Lacasse Y, Goldstein R, Lasserson TJ, Martin S. Pulmonary rehabilitation for chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2006;4:CD003793. [7] Lacasse Y, Martin S, Lasserson TJ, Goldstein RS. Meta-analysis of respiratory rehabilitation in chronic obstructive pulmonary disease: a Cochrane systematic review. Eura Medicophys 2007;43:475–85. [8] Cheng M. Master Cheng’s thirteen chapters on T’ai Chi Chuan. New York: Sweet Chi Press; 1982. [9] Yan J, Guo Y, Yao H, Pan L. Effects of Tai Chi in patients with chronic obstructive pulmonary disease: preliminary evidence. PLoS ONE 2013;8: e61806. [10] Yeh GY, Wood MJ, Lorell BH, Stevenson LW, Eisenberg DM, Wayne PM, et al. Effects of tai chi mind-body movement therapy on functional
[13]
[14]
[15]
[16] [17]
[18]
[19]
[20]
[21]
status and exercise capacity in patients with chronic heart failure: a randomized controlled trial. Am J Med 2004;117:541–658. Lan C, Lai JS, Chen SY, Wong MK. 12-Month Tai Chi training in the elderly: its effect on health fitness. Med Sci Sports Exerc 1998;30:345–51. Lan C, Lai JS, Chen SY, Wong MK. Tai Chi Chuan to improve muscular strength and endurance in elderly individuals: a pilot study. Arch Phys Med Rehabil 2000;81:604–7. Yeh GY, Roberts DH, Wayne PM, Davis RB, Quilty MT, Phillips RS. Tai Chi exercise for patients with chronic pulmonary obstructive disease: a pilot study. Respir Care 2010;55:1475–82. Chan AW, Lee A, Suen LK, Tam WW. Effectiveness of a Tai Chi Qigong program in promoting HR-QoL and perceived social support in COPD clients. Qual Life Res 2010;19:653–64. Chan AW, Lee A, Suen LK, Tam WW. Tai Chi Qigong improves lung functions (sic) and activity tolerance in COPD clients: a single blind, randomized controlled trial. Complement Ther Med 2011;19:3–11. Chetta A, Pisi G, Aiello M, Tzani P, Olivieri D. The walking capacity assessment in the respiratory patient. Respiration 2009;77:361–7. Brismee JM, Paige RL, Chyu MC, Boatright JD, Hagar JM, McCaleb JA, et al. Group and home-based Tai Chi in elderly subjects with knee osteoarthritis: a randomized controlled trial. Clin Rehabil 2007;21:99–111. Church J, Goodall S, Norman R, Haas M. An economic evaluation of community and residential aged care falls prevention strategies in NSW. N S W Public Health Bull 2011;22:60–8. Cahalin LP, Braga M, Matsuo Y, Hernandez E. Efficacy of diaphragmatic breathing in persons with chronic obstructive pulmonary disease: a review of the literature. J Cardpulm Rehabil 2002;22:7–21. Lee SJ, Lee SH, Kim YE, Cho YJ, Jeong YY, Kim HC, et al. Clinical features according to the frequency of acute exacerbatiOn in COPD. Tuberc Respir Dis (Seoul) 2012;72:367–73. Sandlund E, Norlander S, Torsten A. The effects of Tai Chi Chuan relaxation and exercise on stress responses and well-being: an overview of research. Int J Stress Manag 2000;7:139–49.
