T'ai Chi as Exercise Among Middle-Aged and Elderly Chinese in Urban China

Abstract

Objectives:

T'ai chi is a form of mind–body practice used as exercise in China, though limited data are available on characteristics of t'ai chi users and factors associated with practice.

Methods:

Characteristics of and factors associated with t'ai chi practice among middle-aged and elder Chinese in Shanghai China were analyzed utilizing baseline data from the Shanghai Women's Health Study and Shanghai Men's Health Study. Logistic regression modeling was used to identify independent factors associated with the practice of t'ai chi among men and women.

Results:

T'ai chi is the most common form of regular exercise in Shanghai China among middle-aged and elderly persons (22%), including among women (28%) and men (15%). Other popular forms of exercise were walking (7%), dancing (4%), and jogging (3%). A majority of adults who practiced t'ai chi used it as their exclusive type of exercise (69%). Overall, t'ai chi practitioners as compared to nonpractitioners were more likely women, older, more educated, retired versus still working, and more likely to report chronic medical conditions including pulmonary, gastrointestinal, and cardiovascular conditions. T'ai chi activity was associated with other health behaviors including nonsmoking, consuming ginseng, and participating in other forms of physical exercise.

Conclusions:

T'ai chi is the predominant form of exercise among middle-aged and elderly Chinese in urban China, particularly among those with older age and chronic medical diseases. Future research is needed to see whether t'ai chi has similar or different benefits than conventional forms of exercise such as walking and jogging.

Introduction

A sian-based mind–body practices consist of a group of similar practices that combine techniques of meditation, movement, and/or breathing. T'ai chi (also known as taiji or t'ai chi chuan) is one type of mind–body practice from China that has now become a popular form of exercise globally. The meaning of t'ai chi chuan translates from Mandarin as “Supreme Ultimate Fist or Boxing,” reflecting t'ai chi's original purpose as an “internal” martial art aimed at developing the practitioner's well-being and strength described as vital energy or chi. T'ai chi has been categorized as a low-to-moderate-intensity exercise (up to four metabolic equivalents).¹ In addition to providing physical activity, mind–body techniques emphasize psychologic aspects of practice such as mental attention and relaxation. These cognitive components of mind–body practices may have distinctive effects from exercise, though this is an emerging area of research.²

While the national prevalence of t'ai chi practice in China is unknown, it is probably one of the most common forms of exercise. A population-based cohort study of women from Shanghai reported that among women who exercise, 79% reported regular t'ai chi practice as exercise.³ A growing body of clinical research supports the use of t'ai chi as an adjunct treatment for various chronic medical conditions.⁴ Among adults in the United States, t'ai chi use is associated with chronic medical conditions.⁵ Further study of individuals who practice t'ai chi may help identify potential health benefits and inform future clinical research. The purpose of this study was to characterize sociodemographic factors, health behaviors, and medical conditions among individuals who practice t'ai chi in Shanghai China, utilizing data from the Shanghai Women's Health Study (SWHS) and Shanghai Men's Health Study (SMHS), two population-based prospective cohort studies.

Methods

Data source

Detailed descriptions of the research methodology for these two cohort studies have been previously published.^6,7 The SWHS identified all women between 40 and 70 years of age living in seven geographically defined areas of urban Shanghai China as eligible participants. Eligible women were identified through administrative offices in the defined areas. Potential participants were approached at their homes by a local health worker and trained interviewer to determine interest in study participation. Interested subjects gave informed consent and completed a survey interview, and anthropometric measurements were taken. In the SMHS, an identical process was used to select and survey eligible men between the ages of 40 and 74 years who lived in eight geographically defined areas of urban Shanghai. In the SWHS, 74,941individuals of 81,170 eligible participants completed the baseline survey between 1997 and 2000 (response rate 92.3%). Among the SMHS, 61,491 individuals of 83,049 eligible participants completed baseline data collection between 2002 and 2006 (response rate 74.0%).

Data on t'ai chi practice as exercise were collected along with other types of physical activity at the baseline survey for both cohort studies. The instrument used to assess physical activity has been validated for both women and men.^8,9 Initially, subjects were asked if they had participated in regular exercise, defined as at least once a week for at least 3 consecutive months, during the past 5 years (yes, no) prior to the survey. Subjects who reported regular exercise were then asked details regarding up to three exercises/sports, including type of exercise/sports, frequency (hours per week), and duration (years of practice) in the past 5 years.

The baseline survey for the SWHS and SMHS also collected information on the sociodemographics (age, education, income, education, work status, longest-held occupation, marital status, body-mass index [BMI]), health behaviors (smoking status, alcohol consumption, tea consumption, ginseng consumption), and chronic medical conditions of study participants. The SWHS also collected additional information related to menopausal status and time spent watching television.

Statistical analysis

Regular t'ai chi practice is the primary outcome of interest for the current analyses. Analyses were performed of women and men separately, and in combination. The prevalence of t'ai chi was estimated as the percentage of men and women reporting regular practice. The quantity of t'ai chi practice is reported as the median frequency (hours/week) and duration (years) with 25th and 75th percentiles. The association of t'ai chi practice with sociodemographic factors, health behaviors, and chronic medical conditions was evaluated. Sociodemographic categories analyzed were sex, age (40–44, 45–49, 50–54, 60–64, or 65–70 years), BMI (<24, 24–27.9, or ≥28 kg/m²), marriage status (married, widowed, separated/divorced, and never married), educational status (none/elementary, middle school, high school, or college or higher), longest held occupation (manual workers, clerical, or professional), and current work status (currently working or retired). Data on income were collected differently between women and men in SWHS and SMHS, respectively; women reported annual family income and men reported monthly individual income. For analyses and reporting, income was categorized into four categories for women (<10,000, 10,000–19,999, 20,000–29,999, or ≥30,000 Yuan annually per family) and men (<500, 500–999, 1000–1999, or >2000 Yuan monthly per individual) labeling income as levels 1, 2, 3, and 4, respectively. Health behaviors were examined including regular cigarette smoking (yes, no), regular alcohol consumption (yes, no), regular tea consumption (yes, no), regular ginseng intake (yes, no), and physical activity other than t'ai chi (yes, no). The following chronic medical conditions were grouped as a single category for analyses: diabetes, high blood pressure, coronary artery disease, myocardial infarction, chronic hepatitis, hepatocirrhosis, emphysema, chronic gastritis, asthma, stroke, and chronic bronchitis (yes, no). In addition, chronic medical conditions were grouped based on organ systems for subanalyses as follows: (1) pulmonary disease: emphysema, chronic bronchitis, or asthma; (2) gastrointestinal disease: chronic hepatitis, hepatocirrhosis, or chronic gastritis; (3) cardiovascular disease or equivalent: -high blood pressure, coronary artery disease, myocardial infarction, stroke, or diabetes. The association of t'ai chi practice with menopausal status (pre- or postmenopausal) and TV watching (≤2, 3–4, or ≥4 hours/day) was also analyzed among women only.

Percentages of t'ai chi and non-t'ai chi practitioners for each sociodemographic variable were age adjusted and compared using χ² tests. Associations between t'ai chi and sociodemographics and health behaviors were analyzed using multivariable logistic regression analysis. In the analysis, a backward elimination strategy was used to build a multivariable model and factors with a p-value of ≤0.05 (Wald statistic) were retained. Secondary analyses were also conducted of our final model for subgroups of chronic disease (pulmonary, gastrointestinal, and cardiovascular) to detect association between t'ai chi and specific types of chronic conditions. Associations are reported by odds ratios and 95% confidence intervals with two-tailed statistical test. Analyses were conducted with SAS version 9.2 for Windows (SAS Institute, Cary, NC).

Results

The prevalence among middle-aged and elderly of t'ai chi and other forms of physical exercise are presented by gender in Table 1. The prevalence of regular t'ai chi practice among all study participants in urban Shanghai was 22.4%. Women and men reported practicing t'ai chi at a rate of 28.2% and 15.4%, respectively. Among all study participants, t'ai chi was the predominant exercise followed by walking (7.4%), dancing (3.5%), and jogging (3.0%). In Table 2, the frequency (times/week) and duration (years) of t'ai chi practice were reported by other forms of physical activity and gender. Most t'ai chi practitioners used t'ai chi as their exclusive form of exercise (69%). Among all t'ai chi practitioners in the past 5 years, t'ai chi was practiced with a median frequency of 3.5 hours a week, and median duration of 4 years. Table 3 reports the age-adjusted characteristics of t'ai chi practitioners versus non-t'ai chi practitioners by gender. T'ai chi practice was more common among older individuals with a median age of 59 years (51–65 years, 25th–75th percentiles) among women and 66 years (57–71 years, 25th–75th percentile) among men. Many women and men who practiced t'ai chi were currently retired (53.7% and 40.4%, respectively). A large majority of t'ai chi practitioners reported middle incomes (levels 2 and 3). Men at the lowest income level reported infrequent t'ai chi practice. A statistically higher number of t'ai chi practitioners reported having some type of chronic medical disease (53.3% of females and 50.6% of males) as compared to non-t'ai chi practitioners (45.7% of females and 48.3% of males). The most frequent chronic medical conditions reported were cardiovascular (31.6% of women and 36.7% of men) and gastrointestinal diseases (25.8% of women and 18.4% of men). T'ai chi practitioners reported a higher prevalence of other forms of physical activity and regular ginseng use as compared to nonpractitioners.

Table 1.

Most Frequent Forms of Regular Physical Exercise by Gender

	Total (n=136,433)	Women (n=74,942)	Men (n=61,491)
Prevalence of physical exercise (%)
T'ai chi	22.43	28.16	15.44
Walking	7.42	1.34	14.83
Jogging	3.01	1.20	5.23
Dancing	3.53	5.02	1.71
Table tennis	^a	^a	1.27
Martial arts/kungfu	^a	1.10	^a

Prevalence of <1% not reported.

Table 2.

Prevalence of Regular T'ai Chi Practice by Other Physical Activity and Gender

	Total (n=136,433)			Women (n=74,942)			Men (n=61,491)
		Hours of t'ai chi per week	Years of t'ai chi per week		Hours of t'ai chi per week	Years of t'ai chi per week		Hours of t'ai chi per week	Years of t'ai chi per week
	Prevalence of t'ai chi (%)	(median, 25th–75th percentiles)		Prevalence of t'ai chi (%)	(median, 25th–75th percentiles)		Prevalence of t'ai chi (%)	(median, 25th–75th percentiles)
T'ai chi	22.43	3.5 (2.5–7.0)	4.0 (2–5)	28.16	4 (3–7)	3 (2,5)	15.44	3.5 (2.5–7.0)	5 (3–5)
T'ai chi and other physical exercise	6.91	5.0 (3.5–7.0)	5.0 (3.0–5.0)	7.81	6.5 (3.5–8.5)	4.0 (2,5)	5.82	3.5 (2.4,7.0)	4.0 (2–5)
T'ai chi only	15.52	3.5 (2.5–7.0)	3.0 (2.0–5.0)	20.35	3.5 (2.5, 7.0)	3.0 (1–5)	9.62	3.5 (2.5–7.0)	3.0 (1–5)

Table 3.

Age-Adjusted Characteristics by T'ai Chi Practitioners Among Chinese Middle-Aged and Elderly Women and Men in Shanghai

	Females				Males
	T'ai chi (%) n=21,107	No t'ai chi (%) n=53,835	p-Value	Prevalence of t'ai chi practice by characteristic (%)	T'ai chi user (%) n=9496	No t'ai chi (%) n=52,004	p-Value	Prevalence of t'ai chi practice by characteristic (%)
Sociodemographics
Age
40–44	10.37	34.75	<0.0001^a	10.48	3.59	16.38	<0.0001^a	3.85
45–49	13.12	23.59		17.90	7.52	25.75		5.06
50–54	14.82	13.77		29.68	10.00	20.36		8.23
55–59	14.64	8.44		40.46	11.63	12.60		14.42
60–64	21.48	9.64		46.62	14.54	8.14		24.59
65–	25.57	9.81		50.54	52.73	16.76		36.48
Education
None/elementary	20.84	22.07	<0.0001^b	44.07	5.90	7.08	<0.0001^b	27.41
Middle school	33.26	37.21		20.86	30.48	33.70		13.17
High school	29.74	27.52		24.16	35.16	36.01		11.95
College and higher	16.15	13.19		30.97	28.45	23.21		20.07
Employment status
Employed	46.31	53.25	<0.0001^b	16.44	56.98	61.74	<0.0001^b	8.16
Unemployed/retired	53.69	46.75		40.42	43.02	38.25		26.75
Income (Yuan)^c
Level 1	14.97	16.43	0.0003^a	31.47	12.35	12.72	0.0535^a	9.07
Level 2	36.53	38.32		27.71	42.40	42.35		17.17
Level 3	29.45	27.85		27.00	35.19	35.20		16.03
Level 4	19.05	17.40		27.97	10.07	9.73		14.01
Marital status
Married	88.87	88.57	0.1051^b	27.19	97.03	97.17	0.5617^b	15.91
Widowed	7.36	7.52		43.18	0.55	0.62		26.30
Separated/divorced	2.88	3.02		21.33	1.00	0.79		9.69
Never married	0.89	0.90		21.28	1.42	1.42		6.43
Longest held Occupation
Housewife	0.22	0.51	<0.0001^b	24.82			<0.0001^b
Professional	31.82	27.93		30.07	29.41	26.12		21.56
Clerical	19.67	20.98		24.49	24.31	21.70		15.12
Manual	48.29	50.58		28.61	46.28	52.18		12.44
Menopausal status
Premenopausal	48.61	50.95	<0.0001^b	14.59	N/A	N/A	N/A	N/A
Postmenopausal	51.39	49.05		41.96
BMI
<18.5	2.88	3.68	<0.0001^a	22.95	3.27	4.40	0.0003^a	11.96
18.5–24.9	62.04	60.87		25.96	63.92	62.52		15.14
25–29.9	30.00	30.19		32.07	30.07	30.50		16.36
≥30	5.08	5.26		34.94	2.73	2.58		17.67
Medical conditions
Chronic disease
Yes	53.34	45.72	<0.0001^b	35.67	50.60	48.28	<0.0001^b	19.91
No	46.66	54.28		21.26	49.39	51.72		11.21
Pulmonary disease
Yes	9.92	8.36	<0.0001^b	36.46	7.13	6.89	0.2689^b	23.60
No	90.08	91.64		27.36	92.87	93.11		14.84
Gastrointestinal Disease
Yes	25.84	20.86	<0.0001^b	33.48	18.42	16.94	<0.0001^b	17.99
No	74.16	79.14		26.64	81.57	83.06		14.90
CVD or equivalent Disease
Yes	31.64	26.87	<0.0001^b	40.31	36.73	34.30	<0.0001^b	22.12
No	68.36	73.13		23.33	63.26	65.70		11.88
Behavioral factors
Other physical Activity
Yes	25.69	10.44	<0.0001^b	51.53	33.17	25.48	<0.0001^b	22.45
No	74.31	89.56		23.99	66.83	74.51		12.99
Regular cigarette smoking
Yes	2.18	3.18	<0.0001^b	30.76	60.47	71.10	<0.0001^b	11.75
No	97.82	96.82		28.09	39.53	28.90		23.89
Regular alcohol consumption
Yes	2.30	2.18	1959 ^b	31.47	30.60	34.04	<0.0001^b	13.68
No	97.70	97.82		28.09	69.40	65.96		16.33
Regular tea consumption
Yes	32.22	29.20	<0.0001^b	26.79	64.97	67.50	<0.0001^b	14.08
No	67.78	70.80		28.75	35.02	32.50		18.21
Regular ginseng intake
Yes	35.80	26.94	<0.0001 ^b	38.58	37.23	31.29	<0.0001^b	20.37
No	64.20	73.06		23.78	62.77	68.71		13.08
TV (hours/day)
≤2	30.36	29.59	<0.0001 ^b	28.51	N/A	N/A	N/A	N/A
3–4	49.23	48.21		28.47
>4	20.42	22.20		27.01

p-Values based on χ² for trend.

p-Values based on a Pearson χ².

Income levels correspond to annual family income for women (<10,000, 10,000–19,999, 20,000–29,999, ≥30,000 Yuan) and monthly income for men (<500, 500–999, 1000–1999, >2000 Yuan) labeled Income levels 1, 2, 3, and 4, respectively.

BMI, body–mass index; CVD, cardiovascular disease; N/A, not available.

In Table 4, factors independently associated with t'ai chi practice among women, men, and in combination were reported including sociodemographics, health behaviors, and chronic medical conditions. Women were more likely to practice t'ai chi than men. Combining both cohorts, t'ai chi was associated with increased age, being married versus never married or separated/divorced, higher educational status, professional versus clerical or manual occupations, and being retired. Chronic medical conditions, including pulmonary, gastrointestinal, and cardiovascular diseases, were associated with increased t'ai chi practice. T'ai chi practitioners were less likely to smoke, and more likely to report regular ginseng consumption and regular participation in other forms of exercise. Among women, postmenopausal status and watching less TV were positively associated with t'ai chi. Among men, chronic diseases were not associated with t'ai chi except for a weak positive association with cardiovascular disease.

Table 4.

Independent Factors Associated with T'ai Chi Practice in Shanghai China

Sociodemographics	Total	Females Adjusted odds ratio ^a	Males
Sex
Male	1.00 (reference)	N/A	N/A
Female	2.60 (2.49–2.72)
Age
40–44	1.00 (reference)	1.00 (reference)	1.00 (reference)
45–49	1.57 (1.49–1.67)	1.60 (1.50–1.70)	1.33 (1.16–1.51)
50–54	2.48 (2.34–2.62)	2.25 (2.09–2.43)	2.11 (1.85–2.40)
55–59	3.45 (3.25–3.67)	2.76 (2.52–3.04)	3.36 (2.95–3.82)
60–64	4.52 (4.25–4.82)	3.33 (3.03–3.67)	5.21 (4.56–5.95)
65–70	6.19 (5.80–6.60)	3.90 (3.54–4.31)	8.19 (7.21–9.32)
BMI
<18.5	0.76 (0.70–0.82)	0.75 (0.67–0.83)	0.77 (0.67–0.87)
18.5–24.9	1.00 (reference)	1.00 (reference)	1.00 (reference)
25–29.9	0.99 (0.96–1.02)	1.00 (0.97–1.04)	1.00 (0.95–1.05)
≥30	0.95 (0.89–1.01)	0.95 (0.88–1.02)	1.02 (0.88–1.17)
Menopausal status
Premenopausal	N/A	1.00 (reference)	N/A
Postmenopausal		1.28 (1.20–1.37)
Marital status
Married	1.00 (reference)	1.00 (reference)	N/S
Widowed	0.95 (0.89–1.00)	0.99 (0.93–1.06)
Separated/divorced	0.86 (0.77–0.96)	0.84 (0.75–0.94)
Never married	0.86 (0.73–1.02)	0.89 (0.72–1.09)
Education
None/elementary	1.00 (reference)	1.00 (reference)	1.00 (reference)
Middle school	1.03 (0.99–1.08)	0.92 (0.87–0.97)	1.09 (1.00–1.19)
High school	1.24 (1.17–1.32)	1.04 (0.98–1.11)	1.11 (1.01–1.22)
College and higher	1.54 (1.29–1.84)	1.14 (1.06–1.23)	1.24 (1.12–1.38)
Occupation
Housewife	N/A	0.43 (0.32–0.57)	N/A
Professional	1.00 (reference)	1.00 (reference)	1.00 (reference)
Clerical	0.95 (0.91–0.99)	0.91 (0.86–0.97)	1.04 (0.97–1.11)
Manual	0.91 (0.88–0.95)	0.93 (0.89–0.98)	0.90 (0.84–0.96)
Work status
Working	1.00 (reference)	1.00 (reference)	1.00 (reference)
Retired	1.71 (1.65–1.77)	1.69 (1.62–1.77)	1.62 (1.53–1.74)
Family income^b
Level 1	N/S	N/S	1.00 (reference)
Level 2			1.15 (1.05–1.26)
Level 3			1.04 (0.94–1.15)
Level 4			1.01 (0.89–1.14)
Medical conditions
Chronic disease
Yes	1.24 (1.20–1.28)	1.32 (1.27–1.37)	N/S
No	1.00 (reference)	1.00 (reference)
Pulmonary disease
Yes	1.09 (1.04–1.15)^c	1.13 (1.06–1.19)^c	N/S
No	1.00 (reference)	1.00 (reference)
Gastrointestinal disease
Yes	1.21 (1.18–1.26)^c	1.25 (1.20–1.30)^c	N/S
No	1.00 (reference)	1.00 (reference)
CVD or equivalent disease
Yes	1.17 (1.13–1.21)^c	1.24 (1.19–1.29)^c	1.07 (1.01–1.12)
No	1.00 (reference)	1.00 (reference)	1.00 (reference)
Behavioral factors
Regular cigarette smoking
Yes	0.67 (0.64–0.70)	0.70 (0.63–0.78)	0.66 (0.63–0.70)
No	1.00 (reference)	1.00 (reference)	1.00 (reference)
Regular tea consumption
Yes	N/S	1.08 (1.04–1.13)	N/S
No		1.00 (reference)
Regular ginseng intake
Yes	1.41 (1.37–1.45)	1.43 (1.38–1.48)	1.34 (1.27–1.41)
No	1.00 (reference)	1.00 (reference)	1.00 (reference)
TV (hours/day)
≤2	N/A	1.00 (reference)	N/A
3–4		0.99 (0.95–1.03)
>4		0.86 (0.81–0.90)
Other physical exercises
Yes	1.89 (1.83–1.96)	2.84 (2.71–2.97)	1.11 (1.05–1.16)
No	1.00 (reference)	1.00 (reference)	1.00 (reference)

Odds ratios (95% confidence interval) derived from separate multivariable model where chronic disease was replaced with subgroups of disease (pulmonary, gastrointestinal, and CVD) while fully adjusting for sociodemographic factors, health behaviors, and medical conditions.

Fully adjusted model for sociodemographics factors, health behaviors, and medical conditions with p-value ≤0.05.

BMI, body–mass index; CVD, cardiovascular disease; N/A, not available.

Discussion

T'ai chi is a common form of exercise among urban Chinese men and women in China, more frequent than any other forms of exercises including walking and jogging. Women and men who regularly practiced t'ai chi as compared to those who did not were older, more educated, and currently not working. T'ai chi practitioners were more likely to have chronic medical conditions including pulmonary, gastrointestinal, and cardiovascular diseases. T'ai chi activity was associated with other healthy behaviors including non-smoking, consuming ginseng, watching less TV, and participating in other forms of exercise.

Previous research has suggested that regular t'ai chi practice improves cardiovascular fitness.^10,11 T'ai chi is categorized as a moderate intensity exercise.¹⁰ The World Health Organization recommends that adults 18 years and older should do at least 150 minutes of moderate-intensity aerobic physical activity throughout the week.¹² In our study population, 28% of women and 15% of men in Shanghai meet the recommended frequency of physical activity through t'ai chi practice alone. In addition, 7.81% of women and 5.82% men in this study population practice t'ai chi along with other forms of exercise.

As an imported exercise from China, t'ai chi is only practiced by 2.5 million people in the United States.⁵ Characteristics of t'ai chi users in the United States were captured in the National Health Interview Survey.^5,13,14 Similar to t'ai chi in China, t'ai chi users in the United States were more likely to have higher education, but there were no associations with t'ai chi use and age in the United States. Individuals who use t'ai chi in the United States were more likely to report musculoskeletal conditions, severe sprains, or asthma, but no associations with gastrointestinal or cardiovascular disease were reported. Comparing U.S. data to the Shanghai cohorts suggests that the demographic using t'ai chi in China is different than that of the United States. In particular, the higher prevalence of t'ai chi practice among the elderly and individuals with cardiovascular disease in China, as compared to the United States, suggests that t'ai chi is generally considered an acceptable and beneficial exercise among more frail individuals. It is important to note that t'ai chi is considered a type of complementary and alternative medicine in the United States¹⁵ reflecting recent historical immigration from China, whereas in China, t'ai chi has been practiced for thousands of years as a conventional form of exercise for mind and body.

The analyses in this study found that individuals were more likely to practice t'ai chi if they reported chronic medical conditions, including pulmonary and cardiovascular conditions. There is increasing though limited research to support the use of t'ai chi for chronic medical conditions. T'ai chi may help individuals with asthma or chronic obstructive lung disease by improving respiratory function.^16

–19 Research also suggests that patients with cardiovascular disease—including those with hypertension,²⁰ congestive heart failure,^19,21,22 and coronary artery disease—may benefit from t'ai chi practice.²³ The long-term impact of t'ai chi on health of this study's cohorts of men and women with these comorbidities will need to be evaluated as follow-up time of these two cohorts increases. While t'ai chi has been studied for other medical conditions including stress reduction and mood disorders,²⁴ balance and fall reduction among the elderly,²⁵ and arthritis,²⁶ SWHS and SMHS did not specifically capture data regarding these conditions.

This study has several limitations. As a cross-sectional study, no causal relationships can be established. Data collected from questionnaires are potentially subject to recall bias. However, previous validation studies have been shown that the SWHS and SMHS physical activity questionnaires can capture the exercise information accurately and reliably.^8,9 Since this study was conducted in a single metropolitan area, Shanghai, the results may not be generalizable to other cities, particularly rural areas or regions of China, because the t'ai chi practice may vary. Also, generalizing results globally is difficult due to potential variations in how t'ai chi is practiced, perceived, or learned indigenously in China as compared to other countries. Baseline data collection for the two cohorts was conducted several years apart, and therefore direct comparison of t'ai chi practice between men and women is not possible. Despite these limitations, this represents the largest analysis of t'ai chi users to date.

T'ai chi is an important type of physical exercise in China, representing the predominate method of exercise among middle-aged and elderly Chinese men and women. A large majority of research on exercise globally has focused on conventional forms including aerobic and resistance training. As a mind–body practice with emphasis on attention, cognition, and relaxation, t'ai chi may have additional or different effects than other types of exercise. Additional epidemiological research of these cohorts may reveal population-level benefits to mind–body practices that will inform future health interventions.

Footnotes

Disclosure Statement

No competing financial interests exist.

References

Lan

, Chen

, Lai

. The exercise intensity of Tai Chi Chuan. Med Sport Sci, 2008; 52:12–19.

Wayne

, Kaptchuk

. Challenges inherent to T'ai Chi research: Part I. T'ai Chi as a complex multicomponent Intervention. J Altern Complement Med, 2008; 14:191–197.

Jurj

, Wen

, Gao

et al. Patterns and correlates of physical activity: A cross-sectional study in urban Chinese women. BMC Public Health, 2007; 7:213.

Ospina

, Bond

, Karkhaneh

et al. Meditation practices for health: State of the research. Evid Rep Technol Assess (Full Rep), 2007; 155:1–263.

Birdee

, Wayne

, Davis

et al. T'ai chi and qigong for health: Patterns of use in the United States. J Altern Complement Med, 2009; 15:969–973.

Lee

, Xu

, Zheng

et al. Physical activity patterns and their correlates among Chinese men in Shanghai. Med Sci Sports Exerc, 2007; 39:1700–1707.

Zheng

, Chow

, Yang

et al. The Shanghai Women's Health Study: Rationale, study design, and baseline characteristics. Am J Epidemiol, 2005; 162:1123–1131.

Jurj

, Wen

, Xiang

et al. Reproducibility and validity of the Shanghai Men's Health Study physical activity questionnaire. Am J Epidemiol, 2007; 165:1124–1133.

Matthews

, Shu

, Yang

et al. Reproducibility and validity of the Shanghai Women's Health Study physical activity questionnaire. Am J Epidemiol, 2003; 158:1114–1122.

10.

Lan

, Chen

, Lai

. Relative exercise intensity of Tai Chi Chuan is similar in different ages and gender. Am J Chin Med, 2004; 32:151–160.

11.

Lan

, Chou

, Chen

et al. The aerobic capacity and ventilatory efficiency during exercise in Qigong and Tai Chi Chuan practitioners. Am J Chin Med, 2004; 32:141–150.

12.

World Health Organization. Global recommendations on physical activity for health. Geneva: WHO, 2010.

13.

Barnes

, Bloom

, Nahin

. Complementary and alternative medicine use among adults and children: United States, 2007. Natl Health Stat Report, 2009; 12:1–23.

14.

Barnes

, Powell-Griner

, McFann

, Nahin

. Complementary and alternative medicine use among adults: United States, 2002. Advance Data, 2004; 343:1–19.

15.

What is CAM? National Center for Complementary and Alternative Medicine, National Institute of Health. http://nccam.nih.gov/health/whatiscam/. 2010 May 24.

16.

Chang

, Yang

, Chen

, Chiang

. Tai Chi Chuan training improves the pulmonary function of asthmatic children. J Microbiol Immunol Infect, 2008; 41:88–95.

17.

Yeh

. Clinical consultation: Should you recommend Tai Chi for your patients with COPD? Literature review of Tai Chi for chronic pulmonary disease. J Resp Dis, 2005; 26:405.

18.

Chan

, Lee

, Suen

, Tam

. Tai chi Qigong improves lung functions and activity tolerance in COPD clients: A single blind, randomized controlled trial. Complement Ther Med, 2011; 19:3–11.

19.

Yeh

, Roberts

, Wayne

et al. Tai chi exercise for patients with chronic obstructive pulmonary disease: A pilot study. Respir Care, 2010; 55:1475–1482.

20.

Yeh

, Wang

, Wayne

, Phillips

. The effect of tai chi exercise on blood pressure: A systematic review. Prev Cardiol, 2008; 11:82–89.

21.

Yeh

, McCarthy

, Wayne

et al. Tai chi exercise in patients with chronic heart failure: A randomized clinical trial. Arch Intern Med, 2011; 171:750–757.

22.

Yeh

, Wayne

, Phillips

. T'ai Chi exercise in patients with chronic heart failure. Med Sport Sci, 2008; 52:195–208.

23.

Lan

, Chen

, Wong

, Lai

. Tai Chi training for patients with coronary heart disease. Med Sport Sci, 2008; 52:182–194.

24.

Wang

, Bannuru

, Ramel

et al. Tai Chi on psychological well-being: Systematic review and meta-analysis. BMC Complement Altern Med, 2010; 10:23.

25.

Leung

, Chan

, Tsang

et al. Tai chi as an intervention to improve balance and reduce falls in older adults: A systematic and meta-analytical review. Altern Ther Health Med, 2011; 17:40–48.

26.

Wang

. Tai chi and rheumatic diseases. Rheum Dis Clin North Am, 2011; 37:19–32.