Background: Heart rate variability (HRV) as an accurate, noninvasive measure of the Autonomous Nervous System (ANS) can reflect mental health (e.g., stress, depression, or anxiety). Tai Chi and Yoga (Tai Chi/Yoga), as the most widely practiced mind–body exercises, have shown positive outcomes of mental health. To date, no systematic review regarding the long-lasting effects of Tai Chi/Yoga on HRV parameters and perceived stress has been conducted. Objective: To critically evaluate the existing literature on this topic. Methods: Five electronic databases (Web of Science, PubMed, Scopus, SportDiscus and Cochrane Library) were searched from the start of the research project to July 2018. Study selection, data extraction, and study quality assessment were independently carried out by two reviewers. The potentially identified randomized controlled trials (RCT) reported the useful quantitative data that were included only for meta-analysis. Results: meta-analysis of 17 medium-to-high quality RCTs showed significantly beneficial effects on HRV parameters (normalized low-frequency, Hedge’s g = −0.39, 95% CI −0.39 to −0.56, p < 0.001, I2 = 11.62%; normalized high-frequency, Hedge’s g = 0.37, 95% CI 0.22 to −0.52, p < 0.001, I2 = 0%; low-frequency to high-frequency ratio, Hedge’s g = −0.58, 95% CI −0.81 to −0.35, p < 0.001, I2 = 53.78%) and stress level (Hedge’s g = −0.80, 95% CI −1.17 to −0.44, p < 0.001, I2 = 68.54%). Conclusions: Stress reduction may be attributed to sympathetic-vagal balance modulated by mind–body exercises. Tai Chi/Yoga could be an alternative method for stress reduction for people who live under high stress or negative emotions.

Objectives: we used a quantitative method to systematically synthesize the emerging literature and critically evaluate the effects of Baduanjin on depression and anxiety in people with physical or mental illnesses. Additionally, we determined if the number of total Baduanjin training sessions is associated with decreased anxiety and depression levels. Methods: both English and Chinese databases were searched for potential studies published between January 1982 and October 2017. The eligible randomized controlled trials were considered for meta-analysis. Effect size (Hedge’s g) was computed for the pooled effects while the random-effect model was set. For moderator analysis; Subgroup meta-analysis for categorical variables and meta-regression for continuous variables were performed. Results: the aggregated result has shown a significant benefit in favour of Baduanjin on anxiety (Hedge’s g = −0.99; CI −1.63 to −0.74) and depression (Hedge’s g = −1.07; CI −1.3 to −0.83). For continuous potential moderators; meta-regression indicated a significant effect for total hours in Baduanjin practice (β = −0.0053; 95% CI −0.009 to −0.0014; p = 0.008). With regard to depression; meta-regression indicated a significant effect for total sessions of Baduanjin practice (β = −0.0023; 95% CI −0.006 to −0.0004; p = 0.028). Conclusions: the encouraging findings indicate the efficacy of Baduanjin exercise in reducing depression and anxiety symptoms in people with physical or mental illnesses. However; the results should be interpreted with caution because of existing methodological limitations (e.g., high risk of bias; Baduanjin combined with other behavioral interventions; and heterogeneity of control groups).

To study the inter-relationships between sleeping hours, working hours and obesity in subjects from a working population. A cross-sectional observation study under the ‘Better Health for Better Hong Kong’ Campaign, which is a territory-wide health awareness and promotion program. 4793 subjects (2353 (49.1%) men and 2440 (50.9%) women). Their mean age (±s.d.) was 42.4±8.9 years (range 17–83 years, median 43.0 years). Subjects were randomly selected using computer-generated codes in accordance to the distribution of occupational groups in Hong Kong. The mean daily sleeping time was 7.06±1.03 h (women vs men: 7.14±1.08 h vs 6.98±0.96 h, P9 h) had the highest BMI and waist in both men and women. Based on multiple regression analysis with age, smoking, alcohol drinking, systolic and diastolic blood pressure, mean daily sleeping hours and working hours as independent variables, BMI was independently associated with age, systolic and diastolic blood pressure in women, whereas waist was associated with age, smoking and blood pressure. In men, blood pressure, sleeping hours and working hours were independently associated with BMI, whereas waist was independently associated with age, smoking, blood pressure, sleeping hours and working hours in men. Obesity is associated with reduced sleeping hours and long working hours in men among Hong Kong Chinese working population. Further studies are needed to investigate the underlying mechanisms of this relationship and its potential implication on prevention and management of obesity.

SAI-CHUEN HUI, S., and P. Y. YUEN. Validity of the modified back-saver sit-and-reach test: a comparison with other protocols. Med. Sci. Sports Exerc., Vol. 32, No. 9, pp. 1655–1659, 2000. Studies have shown that the classical sit-and-reach (CSR) test, the modified sit-and-reach (MSR), and the newly developed back-saver sit-and-reach (BS) test have poor criterion-related validity in estimating low-back flexibility but yielded moderate criterion-related validity in hamstring flexibility. The V sit-and-reach (VSR) test was found to be practical but the validity has not been established. The purpose of this study was to propose a modified back-saver sit-and-reach (MBS) test, which incorporated all advantages of the various protocols, and to compare the criterion-related validity and reliability of all these tests. 158 college students (F = 96, and M = 62; age = 20.77 ± 2.51) performed CSR, VSR, BS (left and right leg), and MBS (left and right leg) tests in a randomized order. Scores from each test were then correlated with the criterion measures. For all sit-reach tests, intraclass reliability (single trial) was very high (r = 0.89–0.98). MBS yielded significant and highest r with low-back and hamstring criterion for men (r = 0.47–0.67) and women (r = 0.23–0.54). The low-back and right hamstring validity of MBS for men were significantly (P < 0.01) higher than those from BS and CSR, whereas no differences in criterion-related validity were found between the MBS and other protocols in women. The ratings of perceived comfort among the sit-and-reach protocols were significantly different (P < 0.001) from each other. The rating for MBS was observed the most comfortable test as compared with other protocols. The MBS test is not only a reliable test for hamstring and low-back flexibility, it is also a more practical with improved validity for hamstring and low-back flexibility in men than previous protocols.

Background Very little research has been done to simultaneously investigate the effects of Tai Chi (TC) on depression and heart rate variability (HRV). This study, therefore, attempted to explore the effects of TC on depression and on HRV parameters. Methods Sixty older individuals with depression score of 10 or above (the Geriatric Depression Scale, GDS) were randomly assigned into two groups: TC (n = 30) and control group (n = 30). Participants in the experimental group participated in a 24-week TC training program (three 60-min sessions per week), whereas individuals in the control group maintained their unaltered lifestyle. Depression and HRV were measured using the GDS and digital electrocardiogram at baseline and after the 24-week intervention. Results The TC had produced significant positive chances in depression and some HRV parameters (mean heart rate, RMSSD, HF, LFnorm, and HFnorm) (p < 0.05), whereas these positive results were not observed in the control group. Conclusions The results of this study indicated that TC may alleviate depression of the elderly through modulating autonomous nervous system or HRV parameters. This study adds to a growing body of research showing that TC may be effective in treating depression of the elderly. Tai Chi as a mild to moderate mind-body exercise is suitable for older individuals who suffer from depression.

This randomized, controlled, assessor-blinded trial sought to examine the therapeutic efficacy of tai chi versus conventional exercise for management of central obesity in adults aged 50 years or o... Visual Effects of Tai Chi or Conventional Exercise on Central Obesity in Adults. This randomized, controlled, assessor-blinded trial sought to examine the therapeutic efficacy of tai chi v... Background: Central obesity is a major manifestation of metabolic syndrome, which is a common health problem in middle-aged and older adults. Objective: To examine the therapeutic efficacy of tai c...