The Effect of Traditional Chinese Exercises on Blood Pressure in Patients with Hypertension: A Systematic Review and Meta-Analysis

In the context of the increasing number of patients with hypertension, exercise intervention is an excellent alternative or adjunctive treatment for hypertension. Traditional Chinese exercises are excellent physical and mental exercise methods. Although some studies have reviewed the effects of Chinese traditional exercise on patients with hypertension, most of the reviews only involved a single category of traditional exercise. Furthermore, few studies have conducted in-depth analysis of the combined intervention methods of traditional Chinese exercise, and there are high heterogeneity. This study evaluates the current clinical evidence of Chinese traditional exercises in the treatment of essential hypertension. A total of 49 randomized controlled trials with 4207 hypertensive patients were selected according to the inclusion criteria by searching all relevant studies from the establishment of six electronic databases until September 10, 2022. Among them, 24 used tai chi and 25 used Qigong, including Yijinjing, Wuqinxi, Liuzijue, Baduanjin, and Guolin Qigong. This study divided four subgroups according to the type of intervention to explore the source of heterogeneity among studies and found that traditional Chinese exercises can assist or even may replace traditional treatments. The results of meta-analysis showed that compared with the use of antihypertensive drugs alone or in health education, the addition of Chinese traditional exercises showed significant effects in regulating the systolic blood pressure and diastolic blood pressure in hypertensive patients. Although the results show that traditional Chinese exercise are effective, the clinical evidence will be affected by the low quality of most randomized controlled trials. More rigorously designed trials are needed in the future to further validate it.


Introduction
Due to the rapid development of human society, people's diet structure and living habits have changed greatly. Te number of patients with hypertension has increased rapidly on account of the excessive intake of high-protein and highfat food, irregular rest, lack of exercise, smoking and drinking, and other bad behaviors. Hypertension is a clinical syndrome in which blood pressure in the blood vessels continuously rises and is considered the "silent killer" [1]. More than a billion people which include more than a quarter of men and a ffth of women are sufering from this disease, and it will be 1.56 billion by 2025, according to the World Health Organization [2]. If the blood pressure is higher than the normal level for a long time, it will lead to myocardial infarction, stroke, coronary heart disease, heart failure, sudden death, and even death if it is not treated in time [3,4]. At present, there are three main methods to treat hypertension, namely, drug therapy, lifestyle intervention, and device intervention, among which drug therapy is the best way to control the blood pressure level. Now, common antihypertensive drugs include calcium channel blockers (CCB), angiotensin converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB), diuretics, and beta blockers fve classes, but long-term use of antihypertensive drugs has side efects, as the growth of the medication time lead to enhanced resistance [5]. In addition, drug treatment imposes a signifcant fnancial burden on the poor. However, the treatment of hypertension is often accompanied by the treatment of lifestyle intervention because most of the hypertension patients are caused by poor lifestyle and primary hypertension. Terefore, lifestyle intervention can efectively reduce the high blood pressure level of some hypertensive patients and efectively reduce the fnancial pressure of patients. Common lifestyle interventions include reducing sodium intake and increasing potassium intake, eating a reasonable diet, controlling weight, no to smoking, limiting alcohol consumption, increasing exercise, and reducing mental stress [4].
As a lifestyle intervention, exercise therapy has been widely used in hospitals. Research shows that regular exercise can reduce cardiovascular death and all risk of death [6]. To lower blood pressure levels, the researchers recommend 30-60 minutes of moderate-intensity exercise four to seven times a week, in addition to daily activities [7]. Te forms of exercise include aerobic exercise, resistance exercise, and stretching exercise [8]. Te common traditional Chinese exercises are Taiji, Baduanjin, Yijinjing, Wuqinxi, Liuzijue, and so on. Taiji is basically made up of 24 movements that emphasize gentleness, slowness, relaxation, meditation, and calm breathing; Baduanjin is a Qigong guidance technique composed of eight groups of movements, combined with meditation and regular breathing; Yijinjing is a ftness Qigong composed of twelve movements; Wuqinxi is a ftness Qigong that imitates the activities of tiger, deer, bear, ape, and bird; Liuzijue is a ftness Qigong that afects the movement of diferent zang-fu organs, meridians, and collaterals, Qi and blood through the different pronunciation of the six words, namely, "Si," "Hu," "Xu," "Chui," and "Xi" [9,10]. Most traditional Chinese exercises are mind-body exercises that combine body movements, breathing patterns, and meditation [11]. Tey can not only exercise people's body but also reduce people's psychological stress and fully improve people's physical and mental health. Recently, they have been widely used as an alternative drug treatment for many chronic diseases, such as Parkinson's disease, stroke, chronic obstructive pulmonary disease, and cancer, and are welcomed by patients with chronic diseases worldwide. For hypertension, Chinese traditional exercise meets the two options of lifestyle intervention to increase exercise and reduce mental stress, which shows that it has the ability to improve the health status of patients with hypertension, and because exercise occupies a small space, it can be exercised at any time in the hospital ward or at home and other places of daily life.
At present, many studies have proved that Tai Chi and Qigong in Chinese traditional exercises can efectively help hypertensive patients to reduce their blood pressure [12,13] and improve their quality of life [10]. But most of the reviews only cover a single category of Chinese traditional exercises, such as Tai Chi or Baduanjin [14,15]. Although previous reviews have described the impact of traditional Chinese exercise in hypertensive patients, most of the meta-analyses have high heterogeneity and do not explain the reasons for the high heterogeneity [16], so the reliability of these metaanalysis results is questionable. Moreover, few previous studies have conducted an in-depth analysis of the joint intervention methods of Chinese traditional exercises. Terefore, this study will take Chinese traditional exercises as a whole and systematically review and evaluate the efects of Chinese traditional exercises combined with antihypertensive drugs and health education on the blood pressure level in patients with essential hypertension so as to provide a reference for subsequent researchers.

Search Strategy and Data Source.
Tis study searched all relevant trials from six electronic databases including PubMed, Web Of Science, Cochrane, CNKI, VIP, and WANFANG DATA from the beginning to September 10, 2022. Te search strategy of each database is shown in Table 1. To ensure a rigorous and thorough study search, two authors independently screened and evaluated all articles retrieved from the database according to the inclusion criteria, and disagreements were discussed and resolved with the third author.

Eligibility Criteria.
In accordance with PICOS (participant, intervention, comparison, outcome, study), the eligibility criteria for this systematic review were as follows: (1) Patients with essential hypertension and no restrictions on nationality, gender, or age (2) Must be randomized controlled trials (3) Te main intervention measure of experimental groups was Tai Chi or Qigong. Qigong included Wuqinxi, Baduan Jin, Yijinjing, Liuzijue, and other Qigong (4) Te intervention measure of control groups included drug therapy, health education, other sports, and no intervention (5) In addition to hypertension, no other serious diseases, such as diabetes, coronary heart disease, apoplexy, and renal failure (6) Blood pressure (systolic and diastolic) was measured Te criteria for exclusion were as follows: (1) No data for extraction (2) Repeated experimental data appeared in several articles (3) Te required outcome measures, SBP (systolic blood pressure) and DBP (diastolic blood pressure), were not available (4) Study protocol (5) Te full text could not be found or is unavailable 2.3. Data Extraction. Te data extraction work shall be carried out by two authors, respectively. If there is any disagreement between the two authors in this step, the third author shall solve the problem. In this study, the following data were extracted: the frst author of the article, year of publication, sample size, diagnostic criteria for hypertension, age of the participants and blood pressure levels before and after treatment, details of the intervention, and outcome measures. Te EndNote 20 reference management tool was used to organize papers and generate citations.

Risk of Bias Assessment. Te criteria in the revised
Cochrane risk-of-bias tool for randomized trails, RoB2, were used to independently assess the methodological quality of trials [17]. Te items included 5 domains of bias: bias arising from the randomization process, bias due to deviations from intended interventions, bias due to missing outcome data, bias in measurement of the outcome, and bias in selection of the reported result.

Statistical Analysis.
Review Manager software (RevMan 5.4, Cochrane Collaboration, 2022) will be used to perform the meta-analysis. Analyses were performed using the mean, standard deviation, and number of participants for each study and a random efects model. Te chi-square test and isquared statistic were used to assess heterogeneity between studies and were considered signifcant when i-squared was greater than 50%. In addition, if at least 10 trials were included in the meta-analysis, publication bias was assessed using funnel plot asymmetry. When p < 0.05, the results will be considered statistically signifcant.

Subgroup Analysis.
To avoid high heterogeneity among the studies, the analyses were divided into four subgroups according to the type of intervention (TCE (traditional Chinese exercise) vs. Nonintervention, TCE + Health Education versus only Health Education. TCE + AHD (antihypertensive drug) versus only AHD, TCE + Health Education + AHD versus Health Education + AHD).

Protocol Registration.
Tis systematic review and metaanalysis were conducted according to the PRISMA 2020 statement: an updated guideline for reporting systematic reviews [18], and the registration number was CRD42022360208.

Study Search
Result. Te process of study search and selection is shown in Figure 1. A total of 2079 articles were retrieved from the databases: PubMed (n � 115), Web of Science (n � 254), Cochrane (n � 95), CNKI (n � 641), CQVIP (n � 359), and WANFANG (n � 615). After eliminating duplicate studies, 1094 articles remained. After reading the title and abstract, 981 articles were screened, and 113 articles were included in the full-text screening. Trough the entire reading, 64 studies were excluded for the following reasons: nonrandomized controlled trial (n � 21), no control group (n � 7), no relevant outcome measures (n � 8), data could not be extracted (n � 15), intervention measures other than traditional Chinese exercise (n � 4), patients with other serious diseases (n � 6), and similar trial data (n � 3). Finally, a total of 49 articles were included in the study.

TCE
, as shown in Figure 10. When analyzed in this subgroup, heterogeneity was signifcantly reduced compared with the intervention in the overall TCE group. , and the heterogeneity was signifcantly lower than that of the overall TCE group intervention because for I 2 � 0, the fxed efects model was used, as shown in Figure 11. Chinese traditional exercise combined with antihypertensive drugs has a signifcant efect on reducing the DBP level in hypertensive patients (MD � −5.12, 95% CI: [−7.18, −3.05], p < 0.00001, and I 2 � 51%), and heterogeneity was signifcantly reduced compared with the overall TCE group intervention, as shown in Figure 12 using the random efects model.  Evidence-Based Complementary and Alternative Medicine not clarify the type of drug used or that there was high heterogeneity due to the intersection of multiple interventions (traditional Chinese exercise, antihypertensive drugs, and health education).

Publication Bias.
Publication bias in 49 RCTS was assessed using funnel plots, and as shown in Figure 15, publication bias in the studies was small.

Discussion
Scientifc evidence has proved that exercise training is efective in treating hypertension. However, for hypertension patients with poor physical condition, there is a certain risk of moderate and high intensity exercise.
Most traditional Chinese exercises are mostly physical and mental exercise with the main purpose of health preservation, which has been widely used in the treatment of various chronic diseases. Tis study systematically reviewed the previous literature with an objective assessment of the efect of TCE on blood pressure levels in hypertensive patients to fnd an appropriate treatment.

Summary of Research
Results. According to the study inclusion criteria, 49 randomized controlled trials with a total of 4207 hypertensive patients were selected. Te study found that the frequency of traditional exercise practice was 5-7 times per week, and each exercise time was 30-60 minutes, which was the most commonly used test setting in the included studies. According to the results of the meta-analysis, the antihypertensive efect was the most obvious in hypertensive patients undergoing Chinese traditional exercise when compared with the nonintervention group. Secondly, in the TCE + AHD + HE group, under the combination of the treatment of the three intervention methods, it also had a very signifcant efect on the reduction of blood pressure. Te third is the TCE + AHD group, and compared with AHD, it also played a signifcant antihypertensive efect. Finally, we have the TCE + HE group, and because there is no drug intervention involved, the antihypertensive efect is not as good as the previous groups, but it is also an excellent option for people who cannot take drugs. Terefore, Chinese traditional exercise can efectively reduce blood pressure levels in hypertensive patients and assist drugs and health education treatment to promote the recovery of patients with hypertension.

Advantages and Limitations.
Since Chinese traditional exercises are physical and mental sports with the main purpose of health preservation, the diference between this study and previous studies is that Chinese traditional exercises are regarded as a whole combined with medicine and health education therapy, rather than individual Tai Chi or Baduanjin alone. Te studies included in this paper showed great heterogeneity frstly, but they had a signifcant efect in reducing the blood pressure level, which was statistically signifcant, and proved that Chinese traditional exercises are superior to the control group in improving the blood pressure level in hypertensive patients. In view of the high interstudy heterogeneity, the study was divided into four subgroups (TCE   Figure 3: Risk of bias summary.  Evidence-Based Complementary and Alternative Medicine versus nonintervention group, TCE + health education versus pure health education group, TCE + AHD versus pure AHD group, and TCE + health education + AHD versus health education + AHD group) to explore the source of interstudy heterogeneity. After further subgroup analysis, the heterogeneity was signifcantly reduced in the TCE vs. nonintervention group, TCE + health education vs. only health education group, and TCE + AHD vs. only AHD group. However, for the TCE + health education + AHD versus health education + AHD group, the heterogeneity did not decrease but increased. Preliminary speculation suggested that the heterogeneity in each study could not be reduced due to diferences among multiple interventions, such as the types of antihypertensive drugs, the content and efect of health education, and so on. Terefore, the adjuvant therapy of Chinese traditional exercise can lower the blood pressure level in hypertensive patients. Although this meta-analysis found a positive efect of the Chinese traditional exercise on the treatment of hypertensive patients, the clinical evidence of their ability to treat essential hypertension may be weakened by the low methodological quality of most included studies. First, most RCT trials only mentioned randomization but did not explain in detail the method and process of randomization. Secondly, most of the experiments did not mention the hidden  47  30  50  40  238  32  20  30  21  36  30  42  77  37  50  19  25  136  27  30  27  68  58  80  25  35  44  55  51  29  17  24  30  98  38  32  16  16  50  30  25  42  24  42  25  30  33  21  26 41  30  18  40  203  32  20  30  21  37  30  42  77  39  50  21  27  130  27  30  28  59  58  77  11  35  40  58  11  29  19  24  30  100  42  32  16  16  50  30  25  42  24  42  25  30  34  20  27 [-22.12, -13.87] Heterogeneity: Tau 2 = 0.00; Chi 2 = 1.12, df = 4 (P = 0.89); I 2 = 0% Heterogeneity: Tau 2 = 10.14; Chi 2 = 9.53, df = 5 (P = 0.09); I 2 = 48% Heterogeneity: Tau [39,58]              problem of allocation, and some experiments used random number table allocation, which has certain risks. All these issues contributed to the risk of bias in this study.

Conclusion
From the results of the present study, we can draw the following conclusions. Compared with the use of antihypertensive drugs alone or in health education, the addition of Chinese traditional exercises showed signifcant efects in regulating the SBP and DBP levels in hypertensive patients. In addition, the study found that for the treatment of hypertension, most of the Chinese traditional exercises are Taijiquan and Baduanjin, while other types of sports such as Wuqinxi, Liuzijue, Yijinjing, and other tests are rare. Moreover, according to the analysis of reduced subgroup heterogeneity, it is suggested that future exercise prescription formulation can be TCE vs. nonintervention, TCE + health education vs. health education, and intervention prescription design of TCE + AHD vs. AHD, which can better refect the efect of traditional exercise on hypertensive patients. In summary, although some evidence can prove that Chinese traditional exercise can have a positive efect on the blood pressure level in hypertensive patients, the evidence is still weak due to the insufcient number of included studies and methodological quality issues. Terefore, it is hoped that more rigorously designed randomized controlled trials with more types of traditional exercise will emerge to confrm the evidence of traditional exercise on blood pressure levels in Chinese patients with hypertension.

Data Availability
Te data used to support the fndings of this study are included within the article and can be made available upon request to the corresponding author.

Conflicts of Interest
Te authors declare that there are no conficts of interest. 14 Evidence-Based Complementary and Alternative Medicine