The efficacy of Tai Chi for essential hypertension: A systematic review and meta-analysis.

AIM: We aimed to assess the impact of Tai Chi interventions on individuals with essential hypertension and to compare the effects of Tai Chi versus control in this population. BACKGROUND: Tai Chi has been extensively utilized in the prevention of essential hypertension. Nevertheless, there is a lack of consensus regarding its benefits for treating essential hypertension. DESIGN: A systematic review and meta-analysis was conducted. DATA SOURCES: We conducted a systematic literature search of the Medline, Scholar, Elsevier, Wiley Online Library, Chinese Academic Journal (CNKI) and Wanfang databases from January 2003 to August 2023. REVIEW METHODS: Using the methods of the Cochrane Collaboration Handbook, a meta-analysis was conducted to assess the collective impact of Tai Chi exercise in controlling hypertension. The primary outcomes measured included blood pressure and nitric oxide levels. RESULTS: The participants consisted of adults with an average age of 57.1 years who had hypertension (mean ± standard deviation systolic blood pressure at 148.2 ± 12.1 mmHg and diastolic blood pressure at 89.2 ± 8.3 mmHg). Individuals who practiced Tai Chi experienced reductions in systolic blood pressure of 10.6 mmHg, diastolic blood pressure of 4.7 mmHg and an increase in nitric oxide levels. CONCLUSIONS: Tai Chi can be a viable lifestyle intervention for managing hypertension. Greater promotion of Tai Chi by medical professionals could extend these benefits to a larger patient population.

How do previously inactive individuals restructure their time to 'fit in' morning or evening exercise: a randomized controlled trial.

The objective of this study was to investigate changes in sedentary and active behaviors when previously inactive adults start exercising in the morning or evening. One-hundred adults with overweight or obesity (BMI ≥ 25 kg/m2) were recruited for a 12-week intervention and randomized to one of three groups: (i) morning exercise (AMEx; 0600-0900); (ii) evening exercise (PMEx; 1600-1900); or (iii) waitlist control. AMEx and PMEx were prescribed self-paced aerobic exercise to achieve a weekly total of 250 min via a combination of supervised and unsupervised training. Sedentary and active behavior times were measured at baseline, mid- and post-intervention using the multimedia activity recall for children and adults. Time spent engaging in physical activity was significantly increased from baseline at both mid- (+ 14-22 min·day-1) and post-intervention (+ 12-19 min·day-1), for AMEx and PMEx. At 12-weeks, participants in both morning and evening exercise groups reported increased time spent Sleeping (+ 36 and + 20 min·day-1, respecitively), and reduced time spent watching TV/playing videogames (- 32 and - 25 min·day-1, respectively). In response to an exercise stimulus, previously inactive adults make encouraging modifications in how they use their time, and the patterns of change are similar with morning and evening exercise.

Psychological symptoms are associated with screen and exercise time: a cross-sectional study of Chinese adolescents.

BACKGROUND: Mental disorders among adolescents have become a worldwide public health problem. This study aimed to estimate the best combination of exercise time and screen time to promote the mental health of Chinese adolescents. METHODS: Participants included 7200 Chinese adolescents aged 13-18 years from six regions of China. Screen and exercise time data were collected via a self-rated questionnaire. Psychological symptoms (e.g., often feeling depressed, school-weary) were evaluated with the "Multidimensional Sub-health Questionnaire of Adolescents". Chi-squared tests and logistic regression analysis were conducted to investigate the differences in and correlations among screen time, exercise time, and psychological symptoms. RESULTS: The overall detection rate of psychological symptoms among Chinese adolescents was 21.4% (22.1% for boys and 20.6% for girls). Psychological symptom detection rates were lowest among adolescents with 1-2 h/d of screen time (19.5%) and those with 30-60 min/d of exercise time (17.3%). Screen time > 2 h/d (OR = 1.38, P < 0.001) and exercise time < 30 min/d (OR = 1.62, P < 0.001) were positively correlated with psychological symptoms. CONCLUSION: Screen and exercise time are associated with psychological symptoms in Chinese adolescents. A combination of 1-2 h/d of screen time and 30-60 min/d of exercise time is provided as a reference for better mental health.

Effects of morning and nocturnal soccer matches on levels of some trace elements in young trained males.

The aim of this study was to comparatively evaluate effect of morning and nocturnal soccer matches induced metabolic stress on plasma levels of iron (Fe), copper (Cu) and zinc (Zn). Twenty male footballers performed two soccer matches in morning and at night on different days. Blood samples were taken before and after match. The levels of Fe, Zn and Cu were measured through an atomic absorption spectrophotometry. Metabolic stress was evaluated by altered malondialdehyde (MDA) levels that measured using High Performance Liquid Chromatography. In morning and at nocturnal soccer matches, levels of MDA (36% and 27%), Fe (37.4% and 38.9%) and Cu (34.8% and 26.8%) were all increased in all subjects, respectively. However, Zn level decreased -4.5 % in morning (n=10 subjects) and -9.4% at nocturnal (n=12 subjects) soccer matches. In addition, Cu/Zn ratio increased significantly 46.6% in morning and 36.6% at nocturnal soccer matches. Soccer match has significant effects on levels of MDA, Fe and Cu but not Zn levels. The results of this study showed that morning soccer match significantly alters levels of MDA and Cu and Cu/Zn ratio compared to nocturnal soccer match.

Does Restrictive Lung Function Affect the Exercise Capacity in Patients with Repaired Tetralogy of Fallot?

Patients with repaired Tetralogy of Fallot (rTOF) have decreased exercise capacity (XC) and restrictive lung function (RLF). Our objective was to determine the association between RLF and impaired XC in patients with rTOF. This was a single center retrospective review of patients with rTOF who underwent a cardiopulmonary treadmill exercise testing and spirometry from 2005 to 2015. Patients with a respiratory exchange ratio ≥ 1.05 and peak heart rate > 90% of predicted value were included. Forced vital capacity (FVC) and Forced expiratory volume in 1st second of forceful expiration (FEV1) were used to classify the lung function. Exercise parameters such as peak oxygen uptake (VO2), % of predicted VO2 (%VO2), Metabolic equivalents (METS), and exercise time (ET) were compared between the two groups (i) compared patients with normal lung function (normal FEV1, FVC, and FEV1/FVC > 80%) (ii) RLF (FVC < 80%, normal or increased FEV1/FVC > 80%). In our cohort (n = 151, 52% male, mean age ± SD of 22.3 ± 9.1 years), patients with RLF (n = 73) compared to those with normal lung function (n = 86) had a lower peak VO2 (30.8 ± 8.6 vs. 36.6 ± 9.8 mL/kg/min; p < 0.001) and shorter exercise time (9:23 ± 1:78 vs. 10:23 ± 1:62 min, p < 0.001). On multivariate regression analysis, RLF was independently associated with reduced XC (VO2%) (ß-coefficient - 0.182, p < 0.02) after controlling for age and gender. RLF is common in patients with rTOF and is associated with decreased XC. The contribution of RLF to reduced XC in this population should be considered prior to therapeutic decisions.

Trend of Endurance Level Among Healthy Inner-City Children and Adolescents Over Three Decades.

The aim of this study was to understand how endurance time, a proxy for physical fitness, has changed in healthy inner-city children and adolescents in the past three decades. This was a retrospective cross-sectional study. This study used exercise stress test in a laboratory of an inner-city teaching hospital. We reviewed all consecutive healthy children and adolescents who underwent an exercise Bruce protocol treadmill test from 1983 to 2010. The study population was divided into five groups of 5-year intervals based on the year of testing. Temporal trend in endurance time was analyzed, adjusting for gender, ethnicity, age, and body mass index (BMI). We analyzed the records of 435 healthy children and adolescents (mean age 12.6 ± 3.2 years, 57% males).There was a significant difference in the mean endurance time between children grouped in 5-year intervals (P < 0.001) with a significant downward trend in endurance time over the years (P < 0.001), especially after 2001. In contrast, there was no statistically significant change in the mean BMI between children grouped in 5-year intervals (P = 0.205). Multivariate linear regression model demonstrated that the date of testing was independently predictive of endurance time, adjusting for age, gender, BMI, and ethnicity (P < 0.001). Gender was the strongest independent predictor of endurance time, followed by age, BMI, and ethnicity. There is a downward trend in endurance time over the 27-year period among inner-city children and adolescents. Temporal decline in endurance time was independent of factors known to affect this parameter, such as age, gender, BMI, and ethnicity. Factors such as deconditioning due to sedentary lifestyle and lack of motivation to endure on the treadmill among later generations may have played a role in such decline.

Optimal strategies for exercise intervention in older people diabetic patients: The impacts of intensity, form, and frequency on glycemic control: An exercise prescription for older people with diabetes.

OBJECTIVE: This study aims to investigate the optimal exercise intensity, type, and weekly duration for improving glycated haemoglobin (HbA1c) and fasting blood glucose (FBG) levels in older people individuals with diabetes. MATERIALS AND METHODS: PubMed, EMBASE, Web of Science and other databases were searched to identify randomised controlled trials (RCTs) starting from January 2000 to February 2024 that reported improved effects on fasting glucose and glycated haemoglobin after different exercises in middle-aged and elderly diabetic patients. Meta-analyses Review Manager V.5.3 was used. RESULTS: Meta-analysis showed that moderate- and high-intensity exercise had a significant effect on HbA1c levels, with a mean difference (MD) of -0.34 (95 % CI: -0.44 ∼ -0.24, p < 0.01) for moderate-intensity exercise and -0.54 (95 % CI: -0.78 ∼ -0.3, p < 0.001) for high-intensity exercise.. Both moderate-intensity and high-intensity exercise demonstrated statistical significance in lowering fasting blood glucose levels (p < 0.001). Additionally, there was no significant difference between aerobic and resistance exercise forms (p= 0.72). Furthermore, for reducing HbA1c levels, engageing in weekly exercise for at least 2.5 hours showed a MD of-0.44(95 % CI:-0.63∼0.25;p<0.001). CONCLUSIONS: In summary, in terms of exercise intensity, medium and high-intensity exercise can significantly reduce HbA1c and FBG levels in middle-aged and older people diabetic patients; in terms of exercise form, the effects of different exercise forms within medium and high-intensity on HbA1c and FBG are not statistically significant; and in terms of exercise time, in moderate-intensity aerobic exercise, older people exercising for more than 2.5 h per week are more beneficial.

The effect of different times of day for exercise on blood glucose fluctuations.

AIMS: This study aims to explore blood glucose variations before and after short-term intensive exercise in the morning or afternoon of a day and the trend of blood glucose fluctuations during exercise in patients with T2DM (type 2 diabetes, T2DM). METHODS: Blood glucose variations of Fouty during morning exercise 8:00-12:00 hours and twenty during afternoon exercise 14:30-18:30 hours). Patients with T2DM discharged from the hospital were analyzed retrospectively, with the baseline data checked through the medical record system before intervention. We were asked to perform seven times of treadmill aerobic exercise, which lasted for 30 minutes with incremental intensity for each time, for two weeks under the supervision of the Continuous Glucose Monitor (CGM) and the heart rate armband. The exercise intensity has been adjusted by the clinicians and specialist nurses from the Department of Diabetes Mellitus according to the blood glucose levels and heart rate curves during exercise; data including the height, weight, body mass index (BMI), waist-to-hip ratio, fasting blood glucose, glycosylated hemoglobin, in-exercise CGM-measured blood glucose value/min, and after-exercise fingertip blood glucose value of patients with T2DM were collected after the intensive exercise (2 weeks). SPSS 22.0 and GraphPad Prism 7 were adopted for statistical analysis using the T-test and ANOVA. RESULT: No difference was observed in the baseline data between the morning and afternoon exercise groups before intervention; compared to the morning exercise group, the fasting C-peptide value (2.15±0.97 vs. 1.53±0.46) in the afternoon exercise group was higher than that in the morning exercise group, with a superior (p=0.029) effect after two weeks of intervention, exhibiting a significant difference in the results. According to the results of repeated variance ANOVA analysis, the time for the appearance of significant improvement in blood glucose in the afternoon exercise group was 5 minutes earlier (11th minute vs 1 minute)than that in the morning exercise group (15th minute vs 1 min); significant differences were observed in both time (p=0.048 vs p<0.01) between the two groups on exercise days, as revealed by the results of bivariate ANOVA; in comparison to the morning exercise group (7.42±1.68), there was a significant difference (p=0.049)in the mean blood glucose between the two groups 25 min after patients with T2DM in the afternoon exercise group (6.25±1.53) started to exercise; in addition, a significant statistical difference (p=0.021) was revealed in the CGM-measured hourly the mean blood glucose on exercise days between the morning(8.18±1.88) and afternoon exercise (6.75±1.40)groups at 4:00 pm in week one and two w. CONCLUSIONS: Glycaemic improvement in the short-term intensive afternoon exercise group may be superior to that of the morning exercise group, which may be related to greater fasting C-peptide secretion and longer effective exercise duration. The time to exercise is a factor affecting blood glucose variations during exercise. However, significant variations in the level of blood glucose during exercise must be further observed through exercise intervention over a more extended period.

Effects of neuroticism on pre-exam irritable bowel syndrome in female middle school students: mediating role of intolerance of uncertainty and moderating role of exercise duration.

Background: China, which is deeply influenced by Confucianism, places special emphasis on students' test scores. Previous studies have shown that neuroticism is associated with irritable bowel syndrome (IBS) in adolescents. However, the mechanisms underlying this association before exams in female secondary school students are unknown. The present study sought to ascertain whether IU mediates the association between neuroticism and pre-exam IBS, and to determine whether exercise duration moderates the relationship between neuroticism and pre-exam IBS. Methods: The sample consisted of 685 Chinese female middle school students (Mage = 14.81, SD = 1.55, range = 11-18) who completed paper questionnaires, including the neuroticism subscale of the Chinese Neuroticism Extraversion Openness Five-Factor Inventory, the IBS Symptom Severity Scale, a simplified version of the Intolerance of Uncertainty Scale, and a movement time questionnaire. Independent samples t-test was used to compare differences between groups and Pearson correlation coefficient was used to investigate the bivariate correlation. The SPSS PROCESS 4.1 plug-in was then used to examine the mediating role of IU as well as the moderating role of movement time between neuroticism and pre-exam IBS. Results: Neuroticism and IU were significantly correlated with pre-exam IBS (r = 0.39, 0.30, respectively; all p < 0.01), and neuroticism was significantly correlated with IU (r = 0.46, p < 0.01). Neuroticism had a direct predictive effect on pre-exam IBS in Chinese female middle school students (ß = 0.32, p < 0.001), and IU also had a positive effect on pre-exam IBS (ß = 0.15, p < 0.001). The mediating effect value of IU on the total effect was 18.09%. The relationship between neuroticism and pre-exam IBS was moderated by movement time (ß = -0.23, p < 0.05). Conclusion: IU plays a mediating role between neuroticism and pre-exam IBS, and exercise time plays a moderating role between neuroticism and pre-exam IBS. These findings provide an evidence for neuroticism intervention, IU management, and pre-exam IBS improvement in female middle school students.

Correlations between aerobic exercise time during physiotherapy and characteristics of patients with subacute stroke: A pilot cross-sectional study.

BACKGROUND: The amount of aerobic exercise time (AET) is an important factor for improving physical function in patients with stroke. However, there is a lack of evidence regarding the factors for AET during physiotherapy, particularly in stroke patients. OBJECTIVE: To investigate the correlation between AET during physiotherapy and characteristics of patients with subacute stroke. METHODS: In this cross-sectional study, 61 hospitalized subacute stroke patients (age = 72 (11) years, (median (interquartile range)) were enrolled and their exercise intensity was measured by wearable sensors (Mio Alpha 2) worn during physiotherapy sessions. All patients were divided into two groups, non-ambulatory group (functional ambulation classification (FAC); 0-2) and ambulatory group (FAC; 3-5). The correlations between AET and patient characteristics were assessed in each group. RESULTS: There was no significant difference in AET between the ambulatory and non-ambulatory groups (9 (12) min vs 5 (10) min, p = .27, respectively). There was a significant correlation between AET and the functional independent measures (FIM) motor score in the ambulatory group (r = 0.52, p = .005), and between AET and the FIM cognitive score in the non-ambulatory group (r = 0.44, p = .008). CONCLUSION: Correlations between AET and patient characteristics were different according to ambulation capacity in patients with subacute stroke.

The Longitudinal Mediating Effect of Smartphone Dependency on the Relationship between Exercise Time and Subjective Happiness in Adolescents.

The phenomenon of adolescents engaging in less physical activity as they age raises several concerns. Among these, we hypothesized that this trend may negatively impact their mental health and smartphone dependency. Thus, the aim of this study was to longitudinally examine the mediating effect of smartphone dependency in the relationship between adolescents' exercise time and subjective well-being. For analysis, publicly available data from the 2018 Korean Children and Youth Panel Survey were utilized, with a total of 2,242 participants' data included in the analysis. Latent growth modeling results revealed a significant linear decrease in adolescents' exercise time and subjective well-being each year, while smartphone dependency exhibited an increasing trend. Furthermore, the significance tests of indirect effects indicated that the mediating effect of the changing trend in smartphone dependency between the changing trends in exercise time and subjective happiness in adolescents was statistically significant. These findings suggest that as grade levels increase, reducing exercise time can lead to higher smartphone dependency among adolescents, ultimately resulting in decreased subjective well-being.

The effects of physical exercise on anxiety symptoms of college students: A meta-analysis.

Objective: This study aimed to evaluate the effect of an exercise intervention on improving and alleviating anxiety symptoms in college students with a meta-analytical approach. Methods: Several databases (e.g., PubMed, Embase, and the Cochrane Library) were used to search for randomized controlled trials (in short, RCTs) on interventions for physical exercise or aerobic exercise in college students with anxiety symptoms. Stata software, version 16.0, was applied sequentially for traditional meta-analysis, subgroup analysis, and publication bias analysis. Results: A total of nine papers were included. The total literature effect [SMD = -0.55, 95% CI = -0.76 to -0.35, Z = 5.38 (P < 0.001)] indicated that physical activity had a significant effect on alleviating anxiety. Subgroup analysis also showed that exercise interventions using aerobic exercise or yoga were effective in relieving anxiety (SMD = -0.39, 95% CI = -0.74 to -0.04; SMD = -0.76, 95% CI = -1.14 to -0.39). Conclusion: Physical activity interventions were shown to have a positive effect on alleviating anxiety in college students. Aerobic exercise was found to be the optimal mode.

The association between meeting physical activity guidelines and academic performance among junior high school adolescents in China-evidence from the China education tracking survey.

Purpose: To examine how well Chinese adolescents meet the physical exercise time and screen time recommendations in the Physical Activity Guidelines for Chinese Residents (2021), and the relationship between adolescents' physical exercise time, screen time and their academic performance. Method: Daily physical exercise time, screen time and academic performance were collected from Grade 8 adolescents (n = 9,449). Academic performance included standardized scores on Chinese, Math and English tests and responses to the School Life Experience Scale. Results: Meeting the physical activity time and screen time in the Physical Activity Guidelines for Chinese Residents was associated with adolescents' academic performance. Specifically, having at least 60 min of physical exercise per day was associated with adolescents' school life experiences compared to adolescents who did not meet the physical exercise time and screen time in the Chinese Residents' Physical Activity Guidelines. Less than 2 h of cumulative screen time per day was associated with adolescent mathematics test scores, English test scores and school life experiences. Meeting both physical exercise time and screen time to be recommended had more significant effects on adolescents' mathematics, Chinese, English and school life experiences. Meeting both the physical exercise time and screen time recommendations in the Physical Activity Guidelines for Chinese Residents was more significantly associated with boys' mathematics test scores, Chinese test scores and School life experience. Meeting both the physical exercise time and screen time requirements in the Physical Activity Guidelines for Chinese Residents had a more significant effect on School life experience for girls. Conclusion: Physical exercise participation of at least 60 min per day and/or less than 2 h of cumulative screen time per day were both associated with adolescent academic performance. Stakeholders should actively promote adolescents to follow the Physical Activity Guidelines for Chinese Residents (2021).

Unbiased comparison and modularization identify time-related transcriptomic reprogramming in exercised rat cartilage: Integrated data mining and experimental validation.

Exercise is indispensable for maintaining cartilage integrity in healthy joints and remains a recommendation for knee osteoarthritis. Although the effects of exercise on cartilage have been implied, the detailed mechanisms, such as the effect of exercise time which is important for exercise prescription, remain elusive. In this study, bioinformatic analyses, including unbiased comparisons and modularization, were performed on the transcriptomic data of rat cartilage to identify the time-related genes and signaling pathways. We found that exercise had a notable effect on cartilage transcriptome. Exercise prominently suppressed the genes related to cell division, hypertrophy, catabolism, inflammation, and immune response. The downregulated genes were more prominent and stable over time than the upregulated genes. Although exercise time did not prominently contribute to the effects of exercise, it was a factor related to a batch of cellular functions and signaling pathways, such as extracellular matrix (ECM) homeostasis and cellular response to growth factors and stress. Two clusters of genes, including early and late response genes, were identified according to the expression pattern over time. ECM organization, BMP signaling, and PI3K-Akt signaling were early responsive in the exercise duration. Moreover, time-related signaling pathways, such as inositol phosphate metabolism, nicotinate/nicotinamide metabolism, cell cycle, and Fc epsilon RI signaling pathway, were identified by unbiased mapping and polarization of the highly time-correlated genes. Immunohistochemistry staining showed that Egfr was a late response gene that increased on day 15 of exercise. This study elucidated time-related transcriptomic reprogramming induced by exercise in cartilage, advancing the understanding of cartilage homeostasis.

Can school health education improve students' physical exercise time? Empirical research based on CEPS (2014-2015) survey data.

Purpose: School health education is an effective strategy for cultivating adolescent physical exercise habits by transmitting healthy knowledge; it helps to form healthy behaviours and encourages students to participate in physical exercise. The purpose of this study was to explore the relationship between school health education and student participation in physical exercise. Methods: CEPS (China Education Penal Survey, 2014-2015) survey data were used to empirically analyse the impact of school health education on the time that students spend on physical exercise and the underlying mechanism of influence. Results: The results showed that receiving a school health education increased the time that students spent on physical exercise. 1) Compared with receiving health education in only primary school or secondary school, receiving health education in both primary and secondary school had a greater impact on students spending time on physical exercise. 2) Receiving a school health education improved the time that students spend on physical exercise by improving students' health perception and their sports interests. 3) Receiving a school health education had a more obvious impact on the physical exercise time of male students, nonrural resident students, and students from multi-child households. These findings can provide a reference for the seasonable settings of health education curriculum in schools.

Morning Exercise Reduces Abdominal Fat and Blood Pressure in Women; Evening Exercise Increases Muscular Performance in Women and Lowers Blood Pressure in Men.

The ideal exercise time of day (ETOD) remains elusive regarding simultaneous effects on health and performance outcomes, especially in women. Purpose: Given known sex differences in response to exercise training, this study quantified health and performance outcomes in separate cohorts of women and men adhering to different ETOD. Methods: Thirty exercise-trained women (BMI = 24 ± 3 kg/m2; 42 ± 8 years) and twenty-six men (BMI = 25.5 ± 3 kg/m2; 45 ± 8 years) were randomized to multimodal ETOD in the morning (0600-0800 h, AM) or evening (1830-2030 h, PM) for 12 weeks and analyzed as separate cohorts. Baseline (week 0) and post (week 12) muscular strength (1-RM bench/leg press), endurance (sit-ups/push-ups) and power (squat jumps, SJ; bench throws, BT), body composition (iDXA; fat mass, FM; abdominal fat, Abfat), systolic/diastolic blood pressure (BP), respiratory exchange ratio (RER), profile of mood states (POMS), and dietary intake were assessed. Results: Twenty-seven women and twenty men completed the 12-week intervention. No differences at baseline existed between groups (AM vs PM) for both women and men cohorts. In women, significant interactions (p < 0.05) existed for 1RM bench (8 ± 2 vs 12 ± 2, ∆kg), pushups (9 ± 1 vs 13 ± 2, ∆reps), BT (10 ± 6 vs 45 ± 28, ∆watts), SJ (135 ± 6 vs 39 ± 8, ∆watts), fat mass (-1.0 ± 0.2 vs -0.3 ± 0.2, ∆kg), Abfat (-2.6 ± 0.3 vs -0.9 ± 0.5, ∆kg), diastolic (-10 ± 1 vs-5 ± 5, ∆mmHg) and systolic (-12.5 ± 2.7 vs 2.3 ± 3, mmHg) BP, AM vs PM, respectively. In men, significant interactions (p < 0.05) existed for systolic BP (-3.5 ± 2.6 vs -14.9 ± 5.1, ∆mmHg), RER (-0.01 ± 0.01 vs -0.06 ± 0.01, ∆VCO2/VO2), and fatigue (-0.8 ± 2 vs -5.9 ± 2, ∆mm), AM vs PM, respectively. Macronutrient intake was similar among AM and PM groups. Conclusion: Morning exercise (AM) reduced abdominal fat and blood pressure and evening exercise (PM) enhanced muscular performance in the women cohort. In the men cohort, PM increased fat oxidation and reduced systolic BP and fatigue. Thus, ETOD may be important to optimize individual exercise-induced health and performance outcomes in physically active individuals and may be independent of macronutrient intake.

High Prevalence of Obesity but Low Physical Activity in Children Aged 9-11 Years in Beijing.

OBJECTIVE: To investigate the prevalence and associated factors of childhood overweight/obesity in the Shunyi district of Beijing, China. METHODS: This study adopted a cross-sectional survey and included 10,855 children aged 6-18 years in the Shunyi district of Beijing, China. Analyses were stratified by age group (6-8, 9-11, 12-14, and 15-18 years). RESULTS: The prevalence of overweight and obesity among children aged 6-18 years was high with 17.62% and 29.05% in boys, 17.57% and 18.04% in girls, respectively. Both boys and girls aged 9-11 years had the highest rate of obesity in comparison with the other age groups, though the differences in children aged 9-11 years and 12-14 years were not statistically significant. Compared with age 6-8 years, age 9-11 years (OR=1.59, 95% CI 1.41-1.79, P<0.01) and 12-14 years (OR=1.26, 95% CI 1.48-1.73, P<0.01) were independently positively associated with obesity. Importantly, in all subjects, the percentages of being physically active (exercise time ≥120 minutes/week) were lower in children aged 9-11 years in comparison to children in other age groups. This phenomenon remained when this comparison was performed respectively in the normal-weight, overweight, and obesity groups. Even after adjustment for other potential confounders, the probability of being physically active (exercise time ≥120 minutes/week) was lower in children aged 9-11 years (OR=0.86, 95% CI 0.78-0.94, P<0.01), but higher in children aged 12-14 years (OR=1.91, 95% CI 1.69-2.17, P<0.01) and aged 15-18 years (OR=2.22, 95% CI 1.85-2.66, P<0.01), when compared with children aged 6-8 years. CONCLUSION: Children aged 9-11 years had a higher prevalence of obesity, but a lower percentage of being physically active. Targeted intervention programs in this key group are needed to address this problem in China.

Healthy behaviors competing for time: associations of sleep and exercise in working Americans.

OBJECTIVE: Exercise and sleep are two important health promoting behaviors, but large parts of the population do not exercise or are chronically sleep deprived. We investigated to what degree exercise and sleep compete with each other and with other waking activities for time. METHODS: Analyses are based on 2003-2016 American Time Use Survey data of a representative sample of N = 47,862 working Americans aged 18-65 years interviewed on weekdays. Models were adjusted for various sociodemographic variables and time spent working on the interview day. RESULTS: Long work hours and several sociodemographic variables were associated both with short sleep and low exercise rates. Respondents who exercised slept on average 15.5 min less (95% CI: -18.4 min; -12.7 min, P < .0001) than those who did not exercise. Sleep duration decreased with exercise duration in a dose-dependent manner. The strongest association between exercise and sleep duration was observed for exercise between 6 AM and 8 AM (ie, before work) and between 9 PM and 11 PM (ie, before bed). However, unless exercise was performed before work in the morning, exercise durations of up to 1 h were not associated with relevantly curtailed sleep. CONCLUSIONS: These results confirm that exercise and sleep compete with each other for time. However, exercise regimens that follow current guidelines are unlikely to curtail sleep substantially, especially since exercise has been shown to positively affect sleep structure and quality. Public health efforts should nevertheless emphasize the importance of both exercise and sleep, and of not sacrificing one activity for the other.

Time of Day and Training Status Both Impact the Efficacy of Caffeine for Short Duration Cycling Performance.

This project was designed to assess the effects of time of day and training status on the benefits of caffeine supplementation for cycling performance. Twenty male subjects (Age, 25 years; Peak oxygen consumption, 57 mL·kg-1·min-1) were divided into tertiles based on training levels, with top and bottom tertiles designated as 'trained' (n = 7) and 'untrained' (n = 7). Subjects completed two familiarization trials and four experimental trials consisting of a computer-simulated 3-km cycling time trial (TT). The trials were performed in randomized order for each combination of time of day (morning and evening) and treatment (6mg/kg of caffeine or placebo). Magnitude-based inferences were used to evaluate all treatment effects. For all subjects, caffeine enhanced TT performance in the morning (2.3% ± 1.7%, 'very likely') and evening (1.4% ± 1.1%, 'likely'). Both untrained and trained subjects improved performance with caffeine supplementation in the morning (5.5% ± 4.3%, 'likely'; 1.0% ± 1.7%, 'likely', respectively), but only untrained subjects rode faster in the evening (2.9% ± 2.6%, 'likely'). Altogether, our observations indicate that trained athletes are more likely to derive ergogenic effects from caffeine in the morning than the evening. Further, untrained individuals appear to receive larger gains from caffeine in the evening than their trained counterparts.

Toward a customized program to promote physical activity by analyzing exercise types in adolescent, adult, and elderly koreans.

The purpose of this study was to examine the relationship between the perceived physical health status of Korean adolescents, adults, and elderly adults and their frequency, intensity, time, and duration of exercise. In 2012, 1,144 adolescents (under 18 years old), 6,474 adults (19-64 years old), and 1,382 elderly adults (over 65 years old) participated in the Korean Survey on Citizens' Sports Participation Project (N = 9,000). The association between self-reported health status and exercise was assessed using multivariate logistic regression analyses, controlling for sex and age. The study found that the health status of adolescents showed little or no association with the frequency, intensity, time, or duration of exercise. However, the health status of adults and elderly Koreans was associated with the frequency, intensity, time, and duration of exercise. The physical condition and health status of adolescents was better than that of adults and the elderly, many of whom had declining health. Our findings show the need for exercise-promotion programs customized for particular age groups. The limitations and strengths of the study are discussed, as well as the implications for future research and managerial applications for promoting exercise in each age group.