Effects of intermittent dieting with break periods on body composition and metabolic adaptation: a systematic review and meta-analysis

CONTEXT

Intermittent dieting incorporated with break periods (INT-B) has recently been promoted as an alternative dietary approach for optimal weight management.

OBJECTIVE

This study assessed the effectiveness of INT-B compared with that of conventional continuous energy restriction (CER) for improving body composition and attenuating metabolic adaptation.

DATA SOURCES

A systematic search was conducted on 6 databases using all available records until July 2023.

DATA EXTRACTION

The extracted data included the lead author, year of publication, population characteristics, intervention protocols, duration, and adherence.

DATA ANALYSIS

Random-effects meta-analyses were conducted for within-group and between-group comparisons of anthropometric and metabolic outcomes. Subgroup moderator analysis was performed for the types of INT-B, intervention duration, and population characteristics.

RESULTS

Of the 1469 records, 12 randomized trials (with 881 participants) were included. Within-group analyses demonstrated significant improvements in body mass, fat mass, body mass index, body fat percentage, and waist circumference following both INT-B and CER, with no significant group differences. However, resting metabolic rate (RMR) was significantly reduced following CER only. The compensatory reduction in RMR was significantly smaller following INT-B compared with CER, suggesting a lesser degree of metabolic adaptation. INT-B had a more significant effect on RMR retention in individuals with overweight/obesity compared with resistance-trained individuals.

CONCLUSION

This review provides up-to-date evidence for INT-B as a viable dietary strategy to improve body composition and attenuate metabolic adaptation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023448959.

Effect of Physical Exercise-Based Rehabilitation on Long COVID: A Systematic Review and Meta-analysis

PURPOSE

The number of persons living with post-coronavirus disease 2019 (COVID-19) conditions or long COVID continues to rise worldwide; however, the etiology and the treatment of long COVID remain nebulous. Therefore, efficient, feasible, and cost-effective therapeutic strategies for a large population with long COVID remain warranted. Physical exercise-based rehabilitation is a promising strategy for long COVID, although its therapeutic effects remain to be determined. This systematic review and meta-analysis aimed to examine the effects of physical exercise-based rehabilitation on long COVID.

METHODS

The electronic databases Medline, Embase, Global Health (Ovid), CINAHL (EBSCO), Web of Science, WHO Global Research Database on COVID-19, LitCovid, and Google Scholar were searched from their inception to November 2022. The identified articles were independently screened by three reviewers, and a random-effects model was used to determine the mean differences in the meta-analysis.

RESULTS

Twenty-three studies involving 1579 individuals who had COVID-19 (752 women) were included. Physical exercise-based rehabilitation showed beneficial effects on long COVID-related symptoms characterized by dyspnea, fatigue, and depression, as well as on the 6-min walk test, forced expiratory volume in 1 s/forced vital capacity, and quality of life in people who had COVID-19.

CONCLUSIONS

Physical exercise-based rehabilitation is a potential therapeutic strategy against long COVID and can be applied as a routine clinical practice in people who have recovered from COVID-19. However, customized physical exercise-based rehabilitation programs and their effects on specific types of long COVID require future large-scale studies.

Association of Sedentary Lifestyle with Risk of Acute and Post-Acute COVID-19 Sequelae: A Retrospective Cohort Study

BACKGROUND

Evidence suggests that coronavirus disease 2019 (COVID-19) survivors could experience COVID-19 sequelae. Although various risk factors for COVID-19 sequelae have been identified, little is known about whether a sedentary lifestyle is an independent risk factor.

METHODS

In this retrospective cohort study, 4850 participants self-reported their COVID-19 sequelae symptoms between June and August 2022. A sedentary lifestyle included physical inactivity (<150 min/week of moderate-to-vigorous intensity physical activity) and prolonged sedentary behavior (≥10 h/day) before the fifth COVID-19 wave was recorded. Logistic regression analysis was performed to determine the relationships between sedentary lifestyle and risk of acute and post-acute (lasting ≥2 months) COVID-19 sequelae.

RESULTS

A total of 1443 COVID-19 survivors and 2962 non-COVID-19 controls were included. Of the COVID-19 survivors, >80% and >40% self-reported acute and post-acute COVID-19 sequelae, respectively. In the post-acute phase, COVID-19 survivors who were physically inactive had a 37% lower risk of insomnia, whereas those with prolonged sedentary behavior had 25%, 67%, and 117% higher risks of at least one symptom, dizziness, and "pins and needles" sensation, respectively. For the acute phase, prolonged sedentary behavior was associated with a higher risk of fatigue, "brain fog," dyspnea, muscle pain, joint pain, dizziness, and "pins and needles" sensation. Notably, sedentary behavior, rather than physical inactivity, was correlated with a higher risk of severe post-COVID-19 sequelae in both acute and post-acute phases.

CONCLUSIONS

Prolonged sedentary behavior was independently associated with a higher risk of both acute and post-acute COVID-19 sequelae, whereas physical inactivity played contradictory roles in COVID-19 sequelae.

The Associations Between Accelerometer-Measured Physical Activity Levels and Mental Health in Children and Adolescents with Intellectual Disabilities During the COVID-19 Pandemic

To examine the associations between physical activity (PA) levels and mental health in children and adolescents with intellectual disabilities (IDs) during the COVID-19 pandemic, 117 participants aged between 6 and 17 years with IDs from 10 Hong Kong special schools were included. There were positive dose-response associations between PA (i.e., light PA, moderate PA, and vigorous PA) and mental health, and participants with higher levels of moderate-to-vigorous PA (MVPA) and self-concept (SC) had better social quality of life (QoL) than those with lower levels of MVPA and SC. Moreover, personal and environmental factors such as age, body mass index, school, sex, ID level, and parental education level influenced the PA levels and QoL in children and adolescents with IDs.

Acute Physiological and Perceptual Responses to Whole-Body High-Intensity Interval Training Compared with Equipment-Based Interval and Continuous Training

Low-volume, time-efficient high-intensity interval training (HIIT), which involves whole-body (WB) callisthenics exercises, has gained worldwide popularity in recent years. However, the physiological and perceptual impact of WB-HIIT in comparison to specialised, equipment-based training is relatively less studied. This study compared the acute physiological and perceptual responses to a single session of WB-HIIT, ergometer-based HIIT (ERG-HIIT) and conventional moderate-intensity continuous training (MICT). Fourteen physically inactive adults (age: 28.4 ± 6.5 years, VO2peak: 31.0 ± 6.2 mL· kg-1· min-1) underwent three main trials (WB-HIIT: 12 x 30-s high-intensity callisthenics workout; ERG: HIIT: 12 x 30-s high-intensity cycling bouts; MICT: 30-min cycling at 50% peak power output) in a randomized cross-over order 3-7 days apart. The mean session heart rate (HR) and perceived exertion were comparable across all three protocols (p > 0.05). WB-HIIT attained a similar peak HR (87.4 ± 9.4 %HRmax) as that of ERG-HIIT (83.0 ± 8.6 %HRmax), and significantly greater than that of MICT (78.7 ± 5.5 %HRmax, p = 0.001). However, WB-HIIT induced significantly higher blood lactate levels (7.2 ± 1.8 mmol/L) compared to both ERG-HIIT (5.1 ± 1.3 mmol/L, p < 0.05) and MICT (3.1 ± 1.5 mmol/L, p < 0.001). The participants reported higher self-efficacy and greater enjoyment with WB-HIIT compared to MICT (p < 0.05). The mean HR and perceived exertion responses to WB-HIIT are comparable to those of equipment-based HIIT and MICT; however, WB-HIIT results in greater metabolic strain than both other modalities. Despite this, the overall perceptual responses to WB-HIIT are positive, suggesting that it could be a viable exercise alternative, especially for individuals with limited exercise time and restricted access to facilities and equipment.

Temporal trends in the physical fitness of Hong Kong children aged 6-12 years between 2003-04 and 2015-16

Low physical fitness in childhood is linked with poor health now and in later life. This study estimated temporal trends in physical fitness for Hong Kong children aged 6-12 years from 2003-04 to 2015-16. Objectively measured body size and physical fitness data for 27,513 children were obtained from four population-representative surveys of Hong Kong primary school students. Temporal trends in means were estimated by population-weighted linear regression. Trends in distributional characteristics were visually described. Overall, there was a small increase in mean height (effect size (ES) = 0.20 (95%CI: 0.13, 0.28)), with a negligible increase (ES < 0.2) in mean body mass. When adjusted for trends in age, gender, and body size, there was a small decline in sit-and-reach performance (ES = -0.43 (95%CI: -0.43, -0.42)), a small improvement in 9-min run/walk performance (9-to-12-year-olds, ES = 0.26 (95%CI: 0.26, 0.27)), with negligible declines in handgrip strength, 6-min run/walk (6-to 8-year-olds), and sit-ups performance. Temporal trends were not always uniform across the population distribution, with declines in run/walk, sit-ups, and sit-and-reach performance generally largest in children with low fitness. Increased national health promotion strategies that address culturally specific factors are encouraged to further improve the existing trends, especially for children with low fitness.

Effects of increasing light versus moderate-to-vigorous physical activity on cardiometabolic health in Chinese adults with obesity

Increasing daily physical activity (PA) is a practical way to decrease the risk of cardiometabolic diseases, while the studies on exercise intensity remain limited. The purpose of the present study was to compare the effects of increasing light PA (LPA) or moderate-to-vigorous PA (MVPA) for 12 weeks on cardiometabolic markers in Chinese adults with obesity. Fifty-three adults were randomly assigned to the 1) control group, 2) LPA group, and 3) MVPA group in free-living settings. The intervention effects on body composition, cardiorespiratory fitness, and cardiometabolic biomarkers were analysed using a generalized estimated equation model adjusted for baseline values and potential confounders. Compared with the control group, the MVPA group showed improvements in body composition, lipids, C-peptide, monocyte chemoattractant protein-1 (MCP-1), interleukin-8, leptin, and E-selectin. A favourable change in triglycerides and E-selectin were observed in the LPA group when compared to the control group. Lastly, improvements in waist circumference, C-reactive protein, and MCP-1 were observed in the MVPA group when compared to those in the LPA group. Although increasing both LPA and MVPA improved certain cardiometabolic biomarkers, the latter may have more benefits. These findings imply that MVPA may reduce cardiometabolic disease risk more effectively than LPA, especially in Chinese adults with obesity.

Temporal Trends in the Physical Fitness of Hong Kong Adolescents Between 1998 and 2015

Low physical fitness in adolescence is linked with increased cardiometabolic risk and early all-cause mortality. This study aimed to estimate temporal trends in the physical fitness of Hong Kong adolescents aged 12-17 years between 1998 and 2015. Physical fitness (9-min run/walk, sit-ups, push-ups, and sit-and-reach) and body size data in a total of 28,059 adolescents tested across five population-representative surveys of Hong Kong secondary school pupils, were reported. Temporal trends in means were estimated at the gender-age level by best-fitting sample-weighted linear regression, with national trends estimated by a post-stratified population-weighting procedure. Overall, there were small declines in 9-min run/walk (effect size (ES)=-0.29 (95%CI: -0.32, -0.26)) and sit-ups performance (ES=-0.24 (95%CI: -0.27, -0.21)), with negligible changes in push-ups and sit-and-reach performance. There were small concurrent increases in both mean height and body mass, with a negligible increase in sum of skinfolds. Trends in mean physical fitness and body size/were not always uniform across the population distribution. The small declines in mean 9-min run/walk and sit-ups performance for Hong Kong adolescents are suggestive of corresponding declines in cardiorespiratory fitness and abdominal/core endurance, respectively. Increased national health promotion strategies are required to improve existing trends.

Methodological Quality of Systematic Reviews on Bodyweight Management Strategies for Children and Adolescents

INTRODUCTION

Systematic reviews (SRs) synthesize empirical evidence from randomized controlled trials, to answer a research question. Methodological flaws in SRs can, however, reduce the trustworthiness of conclusions, subsequently hindering decision making. We aimed to appraise the methodological quality of existing SRs on bodyweight management strategies for children and adolescents.

METHODS

We searched Cochrane Database of Systematic Reviews, MEDLINE, EMBASE, and SPORTDiscus. A MeaSurement Tool to Assess systematic Reviews (AMSTAR 2) was used to evaluate the methodological quality of SRs including 16 individual AMSTAR 2 domains and the total AMSTAR score. Association between bibliographical characteristics and total AMSTAR score of SRs was explored using multiple linear regression analysis.

RESULTS

Three critical domain-specific items of AMSTAR 2 among the included SRs showed unsatisfactory results including (i) justifying deviation from their SR protocols, (ii) using comprehensive literature search strategies, and (iii) giving details of both included and excluded studies. "More recent publication year journal," "higher impact factor of the journal," and "greater number of review authors" were associated with better methodological quality of the included SRs.

CONCLUSIONS

Future SRs' authors in the field of bodyweight management strategies for children and adolescents should improve the following criteria: (i) justify deviations from SR protocol, (ii) explain selection of the included study designs, (iii) use comprehensive literature search strategy, (iv) give details for both included and excluded studies, (v) report funding sources among included studies, and (vi) assess the potential impact of risk of bias among the included studies on meta-analysis results.

A novel physical functioning test to complement subjective questionnaires in chronic low back pain assessments

BACKGROUND CONTEXT

Lifting disability commonly affects patients with chronic low back pain (CLBP) and may not correlate with the existing lifting-related physical assessment tests, such as the loaded forward reach (LFR) test.

PURPOSE

The Lift and Place (LAP) test was developed to assess lifting disability in CLBP based on known risk factors. The LAP test was compared with established physical assessment test, including the LFR test and self-reported disability questionnaires.

STUDY DESIGN/SETTING

This cross-sectional study measured self-reported disability questionnaires along with LAP and other physical assessment test results PATIENT SAMPLE: Eighty three CLBP and 82 asymptomatic participants aged 18 to 55 with normal BMI according to WHO classification.

OUTCOME MEASURES

Oswestry disability index (ODI), Roland-Morris disability questionnaire (RMDQ), Numerical Pain Rating Scale, Trunk Extensor Endurance test, 5 Repetition Sit-To-Stand test, LAP and LFR test.

METHODS

Physical assessment test scores were compared between the two groups. The correlation of assessment test scores with ODI and RMDQ in patients with CLBP was calculated. Receiver operating characteristic (ROC) curve analysis was performed to calculate the area under the curve (AUC) of each assessment tests. Assessment tests, ODI, and RMDQ were measured twice for CLBP patients on separate days to calculate the test-retest intraclass correlation (ICC) reliability. Two researchers scored the assessment tests independently to calculate the inter-rater ICC.

RESULTS

Patients with CLBP were slower in the LAP test (CLBP vs asymptomatic: 21.6±4.9 s vs 18.6±3.6 s) and had shorter reach in the LFR test (CLBP vs asymptomatic: 33.6±6.0 cm vs 36.3±6.6 cm). The LAP was correlated with both ODI (r=0.418) and RMDQ (r=0.390), while the LFR was not. In the ROC analysis, the LAP and LFR bore AUCs of 0.685 and 0.379, respectively. Their test-retest ICCs were 0.913 and 0.858, and their inter-rater ICCs were 0.997 and 0.969, respectively.

CONCLUSIONS

The LAP test demonstrated higher reliability and significant correlation with the ODI and RMDQ, indicating its potential as performance assessment for lifting disability in CLBP. Further studies should investigate the use of LAP and other physical assessments for rapid CLBP screening.

Effects of Wearing a Mask During Exercise on Physiological and Psychological Outcomes in Healthy Individuals: A Systematic Review and Meta-Analysis

BACKGROUND

Wearing face masks in public is an effective strategy for preventing the spread of viruses; however, it may negatively affect exercise responses. Therefore, this review aimed to explore the effects of wearing different types of face masks during exercise on various physiological and psychological outcomes in healthy individuals.

METHODS

A literature search was conducted using relevant electronic databases, including Medline, PubMed, Embase, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials on April 05, 2022. Studies examining the effect of mask wearing (surgical mask, cloth mask, and FFP2/N95 respirator) during exercise on various physiological and psychological parameters in apparently healthy individuals were included. For meta-analysis, a random effects model was used. Mean difference (MD) or standardized MD (SMD) with 95% confidence intervals (CI) were calculated to analyze the total effect and the effect in subgroups classified based on face mask and exercise types. The quality of included studies was examined using the revised Cochrane risk-of-bias tool.

RESULTS

Forty-five studies with 1264 participants (708 men) were included in the systematic review. Face masks had significant effects on gas exchange when worn during exercise; this included differences in oxygen uptake (SMD - 0.66, 95% CI - 0.87 to - 0.45), end-tidal partial pressure of oxygen (MD - 3.79 mmHg, 95% CI - 5.46 to - 2.12), carbon dioxide production (SMD - 0.77, 95% CI - 1.15 to - 0.39), and end-tidal partial pressure of carbon dioxide (MD 2.93 mmHg, 95% CI 2.01-3.86). While oxygen saturation (MD - 0.48%, 95% CI - 0.71 to - 0.26) decreased slightly, heart rate was not affected. Mask wearing led to higher degrees of rating of perceived exertion, dyspnea, fatigue, and thermal sensation. Moreover, a small effect on exercise performance was observed in individuals wearing FFP2/N95 respirators (SMD - 0.42, 95% CI - 0.76 to - 0.08) and total effect (SMD - 0.23, 95% CI - 0.41 to - 0.04).

CONCLUSION

Wearing face masks during exercise modestly affected both physiological and psychological parameters, including gas exchange, pulmonary function, and subjective discomfort in healthy individuals, although the overall effect on exercise performance appeared to be small. This review provides updated information on optimizing exercise recommendations for the public during the COVID-19 pandemic.

SYSTEMATIC REVIEW REGISTRATION NUMBER

This study was registered in the International Prospective Register of Systematic Review (PROSPERO) database (registration number: CRD42021287278).

Moderate-vigorous physical activity attenuates premature senescence of immune cells in sedentary adults with obesity: a pilot randomized controlled trial

Despite the well-known senolytic effects of physical exercise on immune cells in older adults, the effect of physical activity (PA) on premature immune senescence in sedentary adults with obesity remains largely unknown. This pilot study aimed to investigate the role of objectively measured physical behaviors and Fitbit watch-based free-living PA intervention in premature senescence of immune cells in sedentary adults with obesity. Forty-five participants were recruited in the cross-sectional analysis, and forty of them further participated in the randomized controlled trial. We found that objectively measured moderate-vigorous PA was independently and inversely correlated with the expression of p16^INK4a and p21^Cip1 in the peripheral blood mononuclear cell (PBMCs) of adults with obesity; however, chronological age, body mass index, body fat, maximal oxygen consumption, light PA, sedentary behaviors, and sleep duration were not. More importantly, the 12-week PA intervention mitigated the elevated p16^INK4a levels in PBMCs, though it showed no effect on p21^Cip1 and senescence-associated secretory phenotypes. Taken together, physical inactivity is an independent determinant of premature senescence in immune cells, while the 12-week PA intervention is a promising strategy to alleviate premature immune senescence in adults with obesity.

Effect of game-based high-intensity interval training program on the executive function of children with ADHD: Protocol of a randomized controlled trial

Background

Attention-deficit/hyperactivity disorder (ADHD) is a common developmental disorder in childhood, with a 5%-6% worldwide prevalence. Children with ADHD often demonstrate impaired executive function, which is closely related to the development of the commonly observed behavioral problems such as inattention, impaired inhibition, and hyperactivity. The purpose of this study is to examine whether a game-based high-intensity interval training (HIIT) program can improve the executive function of children with ADHD, compared with a traditional structured aerobic exercise program and a non-treatment control group.

Methods/Design

A total of 42 children with ADHD will be recruited to participate in this three-arm school-based randomized controlled trial. An 8-week specially designed game-based HIIT (GameHIIT) program and a traditional game-based structured aerobic exercise (GameSAE) program will be delivered to those children randomly assigned to these two intervention groups, while the children in the control group will maintain their regular physical activity over the same period. A number of outcome measures including executive function, cerebral hemodynamic response, physical activity, physical fitness, and enjoyment and adherence to the intervention will be assessed for both groups at baseline (T0), immediately after the intervention period (T1), and after the follow-up period (T2).

Discussion

HIIT has recently emerged as a feasible and efficacious strategy for increasing physical health outcomes and cognitive function, including executive function, in healthy young people. However, research has yet to investigate whether the executive function of children with ADHD can be effectively enhanced through HIIT. If, as hypothesized, GameHIIT program improves outcomes for children with ADHD, the present research will inform the development of targeted exercise programs that can be more broadly used with this particular population.

Parental Factors Associated With Physical Activity Among East Asian Children/Youth: A Meta-Analysis Based on the Active Healthy Kids Report Cards

Insufficient physical activity (PA) is a leading risk factor for mortality. The Active Healthy Kids Report Cards provide comprehensive evidence related to PA in children/adolescents. Associations of (1) parental support for PA with amount of moderate-to-vigorous-intensity PA (MVPA) performed by children/adolescents and (2) amount of MVPA performed by parents with amount of MVPA performed by children/adolescents, as indicated by Report Cards, have not been critically synthesized in meta-analysis. We selected data in Asian countries/regions Report Cards and performed meta-analyses to assess pooled associations of influence indicators and behavior indicators among children/adolescents in Asian countries/regions. Our meta-analyses included five studies that assessed association of parental support or MVPA performance with child/adolescent MVPA performance. Positive association was observed between the amount of time spent by parents on MVPA per week, regardless of gender, and the amount of time spent by children and adolescents on MVPA per week (r = .11; 95% confidence interval [CI] [0.06, 0.16]; I² = 40%; p < .0001). In East Asia, the amount of MVPA performed by parents appears to be an important factor influencing the participation of children/adolescents in PA.

Active video game on children and adolescents' physical activity and weight management: A network meta-analysis

We synthesized evidence on the effectiveness of active video games (AVGs) versus no AVG-applied comparators on various physical activity (PA) levels and weight management outcomes in children and adolescents. We analyzed the comparative evidence on different sub-categories of AVGs and ranking the best option. An overview of systematic reviews (SRs) and network meta-analysis (NMA) (PROSPERO: CRD42021248499) was employed. A search for relevant literature published in English was conducted in six electronic databases from their inception until April 2021. SRs consisting of randomized control trials (RCTs) and satisfying our PICOS inclusion criteria were included. RCTs included were a comparison of groups among children and adolescents between 6 and 21, where groups with AVG interventions were compared with groups without them. Direct head-to-head pairwise meta-analyses were conducted using weighted mean difference between the two groups, and the comparative effectiveness of different sub-categories of AVGs was analyzed indirectly using NMA. Overall, 17 SRs were identified from the 6036 screened citations. Of these, 350 citations were retrieved, and 12 RCTs were finally included. Compared with no AVG group, AVG groups were shown to be more effective in achieving vigorous, moderate-to-vigorous, and moderate PA levels, and decreased BMI and body fat. NMA showed that rhythmic dance games had the highest probability of being the most effective sub-category for reducing BMI. AVGs are effective in attaining vigorous, moderate to vigorous, and moderate PA levels, and reducing BMI and body fat among children and adolescents. Dance appears to be the best option for reducing BMI among AVG subcategories.

Movement behaviors and mental health of caregivers of preschoolers in China during the COVID-19 pandemic

This study aimed to examine the associations between physical activity (PA), sedentary behavior (SB), sleep, and the mental health of caregivers of preschool children following the COVID-19 outbreak. From 5 October to 16 December 2020, responses from 2476 respondents in China were collated through an online survey or a written questionnaire. Movement behaviors (PA, SB, screen time, and sleep), mental health (depression, anxiety, and stress), and demographic information were self-reported by the respondents. Linear mixed models were used for data analysis. Valid responses were received from 2002 caregivers (35.5 ± 4.9 years old, 76.3% females) of children between 3 and 6 years old in China (Hong Kong 3.2%, Shanghai 20.6%, Guangzhou 34.1%, Guiyang 26.7%, Xuzhou 11.3%, Xi'an 4.1%). A higher level of PA was associated with a lower score of depression, while lower SB and longer sleep duration were associated with lower scores of depression, anxiety, and stress. Meeting the Canadian 24-h movement guidelines was associated with less symptoms of depression, anxiety, and stress. Higher PA was associated with lower levels of depression, while longer sleep and lower SB were associated with better scores of depression, anxiety, and stress. Meeting the Canadian 24-h movement guidelines has been associated with better mental health during the COVID-19 pandemic. Interventions to improve mental health among caregivers should involve enhancing their overall movement behaviors.

Does the gut microbiota contribute to the antiobesity effect of exercise? A systematic review and meta-analysis

OBJECTIVE

The aim of this study was to assess gut microbiota modifications after exercise in humans and animal models with obesity or type 2 diabetes and their role in exercise-induced weight loss.

METHODS

A systematic search of six databases was conducted on July 31, 2021. The extracted data on body fat or body weight from human and animal studies were analyzed using random-effects meta-analysis.

RESULTS

A total of 28 studies were included, with all studies reporting exercise-induced gut microbiota modifications; however, the modified taxa varied among studies. Proteobacteria was the only taxa reported to be altered by exercise in more than one human and one animal study. Taxa belonging to Firmicutes were the most responsive to exercise in humans and mice, whereas Proteobacteria taxa were the most responsive to exercise in rats. A meta-analysis was conducted to examine the weight-lowering effect of exercise based on data subgrouped by altered or unaltered α-diversity or β-diversity. The association between the weight-lowering effect of exercise and altered β-diversity was observed in humans with obesity but not in animals.

CONCLUSIONS

These findings suggest that gut microbiota modifications contribute to exercise-induced weight loss in obesity; however, their precise contributions, especially those of taxon-level variations, remain to be investigated.

Alternating high-intensity interval training and continuous training is efficacious in improving cardiometabolic health in obese middle-aged men

Background

High-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) alone has been shown to improve metabolic health, but the effects of alternating the two training approaches as often practiced in real life remained unclear.

Purpose

To examine the effects of HIIT or MICT alone or alternating HIIT-MICT on cardiometabolic responses in inactive obese middle-aged men.

Methods

Forty-two participants (age: 42 ± 5 y; BMI: 26.3 ± 2.1 kg m⁻²) were randomly assigned to four groups: HIIT (12 x 1-min running bouts at 80–90% HR_max interspersed with 1-min active recovery at 50% HR_max), MICT (40-min brisk walk at 65–70% HR_max), alternating HIIT-MICT or a non-exercise control group (CON). Exercise sessions were conducted three times per week for 16 weeks. Maximal oxygen uptake (VO_2max), body composition (by bioelectrical impedance analysis), blood pressure, fasting blood glucose, insulin resistance (HOMA-IR) and lipid profile were assessed at baseline and after the 16-week intervention. Enjoyment and self-efficacy were also assessed at the end of intervention.

Results

All exercise groups showed a similar VO_2max increase of ∼15% (HIIT: 34.3 ± 4.4 vs 39.1 ± 5.4; MICT: 34.9 ± 5.0 vs 39.4 ± 7.2; and alternating HIIT-MICT: 34.4 ± 5.0 vs 40.3 ± 4.6 mL kg⁻¹min⁻¹) compared to baseline and CON (all p < 0.05). Weight, BMI, % fat and waist circumference also showed similar reductions in all exercise groups compared to baseline and CON (all p < 0.05). No significant group difference was observed for all blood markers. Compared to baseline, total cholesterol decreased after HIIT-MICT, while HIIT significantly decreased fasting insulin level and improved insulin resistance (p < 0.05). Enjoyment, self-efficacy and adherence were similar among all exercise groups.

Conclusion

HIIT or MICT alone or alternating HIIT-MICT similarly improve cardiovascular fitness and body composition in obese middle-aged men despite differences in total training volume and time commitment.

The Associations Among Physical Activity, Quality of Life, and Self-Concept in Children and Adolescents With Disabilities: A Moderated Mediation Model

OBJECTIVES

This study aimed to examine a moderated mediation model of the associations among physical activity (PA), quality of life (QoL), and self-concept (SC) in children and adolescents with physical disabilities (PDs) and intellectual disabilities (IDs).

MATERIALS AND METHODS

A total of 288 children and adolescents with PDs and IDs, aged between 6 and 17 years, were recruited from 16 special schools in Hong Kong. PA, QoL, and SC were measured using the Physical Activity Questionnaire for Older Children (PAQ-C), Paediatric Quality of Life Inventory (PedsQL), and Physical Self-Description Questionnaire Short Form, respectively. Mediation (i.e., PA, QoL, and SC) and moderation analyses (i.e., age, sex, and parental education level) were conducted by structural equation modelling (SEM) using the M plus and PROCESS macro for SPSS.

RESULTS

Physical activity (PA) was positively associated with SC (PDs: β = 0.373; IDs: β = 0.343), and SC significantly mediated the associations between PA and QoL in children and adolescents with PDs (parent proxy-report QoL: β = 0.114; self-report QoL: β = 0.141) and IDs (self-report QoL: β = 0.204). The mediating effects of SC accounted for 16 and 15% of the total effects of PA on QoL (parent proxy-report and self-report) respectively, in participants with PDs, and 8 and 4%, respectively, in those with IDs. Males and participants with higher parental education levels reported stronger associations among PA, QoL, and SC than their counterparts.

CONCLUSION

This study supports mediating and moderating effects on the associations among PA, QoL, and SC in children and adolescents with PDs and IDs. Future researchers should consider PA intervention in mental health services and provide tailor-made PA programmes based on personal and environmental factors for children and adolescents with disabilities.

Effect of Wearing Surgical Face Masks During Exercise: Does Intensity Matter?

Face masks are widely recommended as means of controlling the coronavirus disease outbreak. This study aimed to examine the physiological and perceptual responses of wearing surgical face masks while exercising at different intensities. Thirteen healthy young adults (mean age, 21.9 ± 1.4 years) conducted randomized crossover trials with or without a surgical face mask. In each trial, participants completed an incremental treadmill protocol, with three 6-min stages (light, moderate, and vigorous at 25, 50, and 75% maximal oxygen uptake, respectively). Physiological outcomes (heart rate, blood lactate, and oxygen saturation level), perceived exertion and discomfort feeling were assessed. No significant differences were observed in physiological outcomes with or without masks at different exercise intensities (p > 0.05). However, the rating of perceived exertion (RPE) was significantly higher when exercising vigorously (mask: 15.5 ± 1.5 vs. no-mask: 14.2 ± 2.1, p < 0.05). Participants wearing masks reported marked discomfort, such as feeling hot, humid, and breathing resistance. Although face mask-wearing during exercise may not have detrimental effects on major physiological parameters, it can increase perceived exertion level and discomfort when the exercise intensity exceeds a certain threshold. Therefore, healthcare professionals should cautiously evaluate each person’s ability to exercise while wearing a mask and tailor their prescription accordingly.

The association between physical activity and mental health in children with special educational needs: A systematic review

The association between physical activity (PA) and mental health in typically developing children has been amply documented, but little is known about the corresponding association in children with special educational needs (SEN). This systematic review aimed to synthesize the evidence for the association between PA and mental health in children with SEN. A systematic literature search of five databases (PsycINFO, SPORTDiscus, PubMed, Web of Science, and CINAHL) was conducted, and the publication year was between October 2010 and February 2021. Two researchers performed abstract and full text screening and extracted the data independently. Inclusion and exclusion criteria followed the PICOS framework, and the quality of eligible studies was assessed using the McMaster critical review form. Eighteen studies that met the inclusion criteria and had quality ratings ≥ 60% were included in this review. PA was positively associated with overall psychological well-being and its subtypes (including enjoyment, self-worth, self-competence, mental wellness, and quality of life), and negatively associated with anxiety and fatigue. Body composition, age, and sex were moderators of the association. The findings of this review indicated that PA was consistently associated with mental health in children with SEN. These associations were the most powerful when PA was conducted in unstructured types such as free play and recess activities. Structured types including physical education classes were more strongly related to mental health than overall PA (combined structured and unstructured types). Future PA interventions are needed to promote mental health in children with SEN.

Effects and dose-response relationship of high-intensity interval training on cardiorespiratory fitness in overweight and obese adults: a systematic review and meta-analysis

This study aims to quantify the effects of high-intensity interval training (HIIT) on cardiorespiratory fitness (CRF) by considering potential moderators and to characterise dose-response relationships of HIIT variables that could maximise CRF improvements in overweight and obese adults. Following a comprehensive search through four electronic databases, 19 studies met eligibility criteria. Random-effects models were applied to weight all included studies and to compute the weighted mean standardised mean differences (SMD_wm). Meta-analysis showed that HIIT was a highly effective approach for improving CRF in overweight and obese adults (SMD_wm = 1.13). Effects were modified by sex and baseline CRF level. Dose-response relationship analysis provided some preliminary data regarding the training period, training intensity, and session duration. However, it is still not possible to provide accurate recommendations currently. Further studies are still needed to identify the most appropriate training variables to prescribe effective HIIT programmes for improving CRF in overweight and obese adults.

Relationships of physical activity and sedentary behaviour with the previous and subsequent nights' sleep in children and youth: A systematic review and meta-analysis

The interrelationships between sleep and daytime movement behaviours have been examined at interindividual level. Studies of within-person, temporal relationships of daytime physical activity (PA) and sedentary behaviour with the previous and subsequent nights' sleep are increasing. The present systematic review and meta-analysis synthesised the results of studies in school-aged children and youth. Eight databases (MEDLINE, PsycINFO, EMBASE, Global Health, PubMed, Web of Science, SPORTDiscus, and CINAHL) were searched for peer-reviewed articles that examined the association between daytime movement behaviours (including PA, sedentary time, or sedentary recreational screen time) and night-time sleep on the same day, or the association between night-time sleep and daytime movement behaviours the next day, in children and youth. A total of 11 studies comprising 9,622 children and youth aged 5-15 years met the inclusion criteria. Sedentary time was negatively associated with the subsequent night's sleep duration (r = -0.12, 95% confidence interval -0.23 to -0.00; I²  = 93%; p = .04). Positive relationships between PA and the previous or subsequent night's sleep duration were observed only for studies that adjusted for accelerometer wear time. There was some evidence suggesting that a longer sleep duration was associated with less sedentary time and a higher proportion of the daytime spent being physically active and vice versa, although the association was weak and based on a limited number of studies. From a clinical perspective, promotion of either sleep hygiene or daytime PA should be planned with considerations of the virtuous or vicious circle between these behaviours and monitor concurrent effects on the others.

Compliance with the WHO 24-hour movement guidelines and associations with body weight status among preschool children in Hong Kong

This study aimed to investigate the extent to which preschool children in Hong Kong meet the WHO 24-hour movement guidelines and to examine the associations between meeting the guidelines and body weight status. Data from 251 preschoolers (141 boys) aged between three and six years old were analysed. The children wore an activPAL for seven consecutive days to measure physical activity and sleep. Their screen time was reported by their parents using validated questions. Their body weight status was classified as underweight, normal weight or overweight/obese. A total of 2.9% of the preschoolers met all three movement guidelines. Children in compliance with the physical activity, screen time and sleep guidelines accounted for 14.5%, 67.4% and 39.0% of the sample, respectively. There was no significant association between meeting the individual or combined guidelines and body mass index or the odds ratio for being of normal weight. Meeting more guidelines was not associated with body mass index or the odds ratio for being normal weight. Compliance with the 24-hour movement guidelines was extremely low among preschool children in Hong Kong. Meeting the 24-hour movement guidelines was not associated with a favourable weight status among preschoolers. Novelty • Compliance with the WHO 24-hour movement guidelines was extremely low for the early years in Hong Kong. • Further evidence is needed to understand the associations between meeting the guidelines and weight status among preschoolers.

Interval training versus moderate-intensity continuous training for cardiorespiratory fitness improvements in middle-aged and older adults: a systematic review and meta-analysis

Interval training has been promoted as a superior, time-efficient exercise strategy for enhancing cardiorespiratory fitness in the ageing population. This study assessed the effectiveness of interval training compared with that of moderate-intensity continuous training (MICT) for improving cardiorespiratory fitness in middle-aged and older adults. Six databases were systematically searched for studies with exercise interventions (minimum 2-week duration). Meta-analyses were conducted for within-group and between-group comparisons of maximal oxygen uptake (VO_2max). Sub-group analysis was performed using the nature of interval training (high-intensity interval training [HIIT] and sprint interval training [SIT]). Of 3,257 studies, 14 were included (429 participants). Within-group analyses demonstrated significant VO_2max improvements (mL/kg/min) following interval training (mean difference: MD = 2.26; 95% confidence interval [CI] = 1.50-3.02) and MICT (MD = 1.34; 95% CI = 0.45-2.23]. When comparing the modes of training, the gain in VO_2max was significantly greater following interval training (MD = 1.10; CI = 0.55-1.64). Sub-group analysis showed that HIIT (MD = 1.04; CI = 0.21-1.88) and SIT (MD = 1.18; CI = 0.60-1.76) resulted in superior VO_2max gain than MICT. This study provides evidence synthesis for interval training as a viable exercise strategy to improve cardiorespiratory function in healthy ageing.

Associations of Sedentary Patterns with Cardiometabolic Biomarkers in Physically Active Young Males

PURPOSE

Sitting time (ST) is a serious global health issue and positively associated with cardiometabolic disease. The present study investigated associations between objectively measured ST, sedentary patterns, and cardiometabolic biomarkers in physically active young males.

METHODS

Cross-sectional analysis was completed in 94 males 18-35 yr of age. Total ST, prolonged sedentary bouts (≥30 min with no interruption), and sedentary breaks (transitions from sitting/lying to standing/stepping) were assessed using activPAL. Lipids, insulin, C-peptide, C-reactive protein (CRP), vascular cellular adhesion molecule-1, intercellular adhesion molecule 1, E-selectin, P-selectin, leptin, resistin, and adiponectin were measured using assay kits. The expression of specific proteins related to endothelial dysfunction was determined using quantitative real-time polymerase chain reaction. Associations between total ST, prolonged sedentary bouts, and sedentary breaks with cardiometabolic biomarkers and total ST and levels of gene expression were assessed using generalized linear models.

RESULTS

Total ST was significantly associated with triglycerides (B = 1.814), insulin (B = 2.117), homeostasis model assessment of insulin resistance (B = 0.071), and E-selectin (B = 2.052). Leptin (B = 0.086), E-selectin (B = 1.623), and P-selectin (B = 2.519) were significantly associated with prolonged sedentary bouts, whereas leptin (B = -0.017) and CRP (B = -0.016) were associated with sedentary breaks. After adjustment for moderate to vigorous physical activity, the associations between triglycerides (B = 2.048) and total ST, and between CRP (B = -0.016) and sedentary breaks, remained significant. E-selectin mRNA levels (B = 0.0002) were positively associated with ST with or without adjustment for moderate to vigorous physical activity.

CONCLUSIONS

Total ST and prolonged sedentary bouts were positively associated with several cardiometabolic biomarkers, with interruptions in ST potentially contributing to reduced cardiometabolic risk in physically active young male adults.

Effect of sedentary behavior interventions on vascular function in adults: A systematic review and meta-analysis

Sedentary behavior (SB) results in hemodynamic alterations within the vasculature, leading to vascular dysfunction that may be attenuated by various interventions. This systematic review and meta-analysis examined the effect of SB interventions on vascular function in adults using seven databases searched on December 17, 2020. All types of SB interventions were included such as short- and long-term interventions (≥7 days) in participants aged ≥18 years. The pooled effect (mean difference) of intervention on three outcomes, namely, flow-mediated dilation (FMD), shear rate (SR), and pulse wave velocity (PWV), was evaluated using random effects meta-analyses. The revised Cochrane risk-of-bias tool for randomized trials was employed to assess the quality of the included studies. Twenty-six studies (21 short-term and six long-term interventions) involving 669 participants from eight countries were included. Evidence from meta-analysis showed that short-term interventions targeting SB improved FMD by 1.50% (95% confidence interval [CI] 1.00-1.99) and increased SR by 12.70 S^-1 (95% CI 7.86-17.54); no significant pooled effect was found for PWV. Long-term SB interventions resulted in a 0.93% increase in FMD (95% CI 0.25-1.62) and had no significant effect on PWV. Findings of this systematic review and meta-analysis suggest that both short- and long-term SB interventions improved FMD but had no effect on PWV. Short-term interventions had a greater effect in improving lower extremity arterial function. Further studies targeting long-term SB interventions on vascular function in adults are warranted.

Associations between weather conditions and physical activity and sedentary time in children and adolescents: A systematic review and meta-analysis

This systematic review and meta-analysis aimed to investigate the associations between weather conditions and physical activity (PA) and sedentary time (ST) in children and adolescents. A systematic search of six databases identified 11,816 articles, of which 26 studies were included in the review. Several weather conditions were included, such as rainfall, temperature, wind speed, day length, sunlight, humidity, snowfall, and clouds. Meta-analyses showed that higher temperatures were associated with more moderate-to-vigorous PA, while lower temperature and heavily rainfall was associated with longer ST. Children and adolescents showed more PA and less ST during favorable weather conditions. Future longitudinal and intervention studies on PA and ST should focus on how weather conditions promote or hinder these behaviors.

Interrupting Prolonged Sitting Reduces Postprandial Glucose Concentration in Young Men With Central Obesity

CONTEXT

Prolonged sitting elevates postprandial metabolic markers, resulting in increased risks of cardiovascular diseases and type 2 diabetes. Interrupting prolonged sitting may reduce these risks. However, more information is needed to understand the patterns of interrupting prolonged sitting to obtain metabolic health benefits.

OBJECTIVE

This study examined the effects of interrupting prolonged sitting with different intensities and durations of walking with an equivalent energy expenditure on postprandial metabolic responses in young Chinese men with central obesity.

DESIGN

A randomized crossover experimental trial was conducted.

SETTING

Participants underwent three 6-hour experiments with a 7-day washout period between each experiment: prolonged sitting, 3 min of light-intensity walking every 30 minutes, and 1.5 minutes of moderate-intensity walking every 30 minutes.

PARTICIPANTS AND SAMPLES

Baseline (fasting) and 6-hour postprandial metabolic glucose and lipid levels were analyzed among 18 young Chinese men with central obesity.

MAIN OUTCOME MEASURES

Generalized estimating equations (adjusted for the potential confounders explaining residual outcome variance (body mass index) and age), trial order, preprandial values, and lead-in activity) were used, and the incremental areas under the curve (iAUC) of each outcome were compared between prolonged sitting and interrupted prolonged sitting conditions.

RESULTS

Compared with prolonged sitting, both interrupting prolonged sitting conditions reduced the iAUCs for glucose (P < .05) but not insulin, C-peptide, triglycerides, or nonesterified fatty acids.

CONCLUSIONS

Both conditions of interrupted prolonged sitting reduced postprandial glucose concentrations in young Chinese men with central obesity when the energy expenditure was equivalent.

Frequency of interruptions to prolonged sitting and postprandial metabolic responses in young, obese, Chinese men

This study aimed to examine the effects of 3-min light-intensity walking every 30 min (3-min) and 6-min light-intensity walking every 60 min (6-min) compared with prolonged sitting (SIT) on the postprandial metabolic responses in young, centrally obese, Chinese men. Twenty-one Chinese men with central obesity (age, 23 ± 4 years; body mass index, 29.8 ± 3.2 kg·m^-2; waist circumference, 98.7 ± 7.1 cm; mean ± SD) underwent three 6-h experiments with a 7-day washout period, SIT, 3-min, and 6-min, in randomized order. Compared with SIT, neither walking condition showed differences in total and net incremental area under the curve (tAUC and iAUC, respectively) for glucose, insulin, nor non-esterified fatty acids. The tAUC and iAUC for triglycerides for the SIT condition (10.8 [9.3, 12.2] and 4.4 [3.7, 5.1] mmol·h·L^-1, respectively; mean [95% confidence interval]) was higher than 3-min (10.4 [9.0, 11.8] and 3.8 [3.3, 4.3] mmol·h·L^-1, respectively, both Ps <0.05) and 6-min (9.6 [8.1, 11.0] and 3.5 [2.9, 4.2] mmol·h·L^-1, respectively, both Ps <0.01) conditions. Interrupting prolonged sitting regardless of frequency-reduced postprandial triglycerides. A higher volume of physical activity may be required to obtain greater glycaemic benefits in young Chinese men with central obesity.

Association of Sedentary Time and Physical Activity With Executive Function Among Children

BACKGROUND

This study aimed to examine individual and combined associations between after-school sedentary time (ST) and daily physical activity (PA) with executive function development in children.

METHODS

The study included 4304 children aged 6 to 12 years. ST and PA were assessed using the International Physical Activity Questionnaire Short Form, and executive function was assessed using the Behavior Rating Inventory of Executive Function (Parent Version). Participants were classified as low (<2 h per day) or high (≥2 h per day) ST and low (not meeting guidelines) or high (meeting guidelines) PA. Resulting groups were defined as 1) low ST/high PA, 2) low ST/low PA, 3) high ST/high PA, and 4) high ST/low PA.

RESULTS

Children in group 4 had the highest mean T-scores for BRIEF indices (48.23 ± 8.44, indicating increased symptoms of executive function dysfunction), followed by those in group 3 (47.10 ± 8.05), group 2 (45.81 ± 7.78), and group 1 (44.41 ± 7.31). ST was positively related to the T-score of all indices, independent of moderate-to-vigorous physical activity (MVPA). Significantly negative associations were observed between MVPA and Metacognition Index only in the high ST subgroup.

CONCLUSIONS

Low ST and high PA were positively associated with executive function development in children. Notably, children with high ST and high PA demonstrated more significant deficits in executive function than those with low ST and low PA, suggesting that intervention efforts should focus on ST reduction in addition to promoting PA.

Results from Hong Kong's 2019 report card on physical activity for children and youth with special educational needs

BACKGROUND

/Objective: The Active Healthy Kids 2019 Hong Kong Report Card on Physical Activity for Children and Youth with Special Educational Needs (SEN) provides evidence-based assessments for nine indicators of physical activity behaviors and related sources of influence for 6- to 17-year-olds with SEN in Hong Kong. This is the first Report Card for this population group in Hong Kong.

METHODS

The best available data between 2008 and 2019 were reviewed by a panel of experts. Following the Active Healthy Kids Global Alliance (AHKGA) development process, letter grades were assigned to nine indicators (Overall Physical Activity, Organized Sport Participation, Active Play, Active Transportation, Sedentary Behaviors, Family & Peers, School, Community & Environment, and Government Strategies & Investments).

RESULTS

Two behavior indicators (Overall Physical Activity: F; Sedentary Behaviors: D+) and two contextual indicators (School: B; Government Strategies & Investments: C-) were assigned a letter grade. The remaining indicators including Organized Sport Participation, Active Play, Active Transportation, Family & Peers, and Community & Environment were not graded due to insufficient data.

CONCLUSIONS

A majority of children and youth with SEN in Hong Kong are physically inactive and have a high level of sedentary behaviors. Schools are ideal settings to promote physical activity for this population. There is a need to develop a comprehensive surveillance system to monitor this population, assess efforts to improve the grades, and promote physical activity opportunities for children and youth with SEN.

COVID-19 Pandemic Brings a Sedentary Lifestyle in Young Adults: A Cross-Sectional and Longitudinal Study

The coronavirus disease 2019 (COVID-19) pandemic continues to pose profound challenges to society. Its spread has been mitigated through strategies including social distancing; however, this may result in the adoption of a sedentary lifestyle. This study aimed to investigate: (1) physical activity (PA) levels, sedentary behavior (SB), and sleep in young adults during the COVID-19 epidemic, and (2) the change in these behaviors before and during the pandemic. A total of 631 young adults (38.8% males) aged between 18 and 35 participated in the cross-sectional study and completed a one-off online survey relating to general information, PA, SB, and sleep. For the longitudinal study, PA, SB, and sleep data, obtained from 70 participants before and during the COVID-19 pandemic, were analyzed. Participants engaged in low PA, high SB, and long sleep duration during the COVID-19 pandemic. Moreover, a significant decline in PA while an increase in time spent in both SB and sleep was observed during the COVID-19 outbreak. The results of this study demonstrated a sedentary lifestyle in young adults during the COVID-19 pandemic, which will assist health policymakers and practitioners in the development of population specific health education and behavior interventions during this pandemic and for other future events.

The effect of low-volume high-intensity interval training on cardiometabolic health and psychological responses in overweight/obese middle-aged men

High-intensity interval training (HIIT) has been proposed as a time-efficient exercise protocol to improve metabolic health, but direct comparisons with higher-volume moderate-intensity continuous training (MICT) under unsupervised settings are limited. This study compared low-volume HIIT and higher-volume MICT interventions on cardiometabolic and psychological responses in overweight/obese middle-aged men. Twenty-four participants (age: 48.1±5.2yr; BMI: 25.8±2.3kg·m^-2) were randomly assigned to undertake either HIIT (10 X 1-min bouts of running at 80-90% HR_max separated by 1-min active recovery) or MICT (50-min continuous jogging/brisk walking at 65-70% HR_max) for 3 sessions/week for 8 weeks (2-week supervised + 6-week unsupervised training). Both groups showed similar cardiovascular fitness (VO_2max) improvement (HIIT: 32.5±5.6 to 36.0±6.2; MICT: 34.3±6.0 to 38.2±5.1mL kg^-1 min^-1, p < 0.05) and %fat loss (HIIT: 24.5±3.4 to 23.2±3.5%; MICT: 23.0±4.3 to 21.5±4.1%, p< 0.05) over the 8-week intervention. Compared to baseline, MICT significantly decreased weight and waist circumference. No significant group differences were observed for blood pressure and cardiometabolic blood markers such as lipid profiles, fasting glucose and glycated haemoglobin. Both groups showed similar enjoyment levels and high unsupervised adherence rates (>90%). Our findings suggest that low-volume HIIT can elicit a similar improvement of cardiovascular fitness as traditional higher-volume MICT in overweight/obese middle-aged men.

A school-based physical activity intervention for children with developmental coordination disorder: A randomized controlled trial

BACKGROUND

Children with developmental coordination disorder (DCD) have lower physical activity (PA) than children with typical development (TD). PA and fundamental movement skills (FMS) are positively associated so interventions that promote FMS of children with DCD are recommended.

AIM

To examine the effects of a school-based FMS training program on motor functions, PA and other psychological outcomes.

METHODS AND PROCEDURES

A total of 131 primary children were allocated to FMS training groups (DCD-FMS n = 35, TD-FMS n = 29), which received FMS training (eight weekly 40-min sessions), or to control groups (DCD-C n = 34, TD-C n = 33), which received conventional physical education lessons. Outcome measures, including accelerometer-assessed PA, motor functions, and self-perceived competence and enjoyment, were measured at baseline, 1-week (immediate effect), 3-months (short-term effect) and 12-months (longer-term effect) after the intervention.

OUTCOMES AND RESULTS

FMS training resulted in improved FMS proficiency and increased PA and enjoyment of activity participation in children. In particular, the DCD-FMS group reported greater enjoyment over time. Some effects were also evident for both short- and longer-term.

CONCLUSIONS AND IMPLICATIONS

The findings suggest that a school-based FMS training program has the potential to promote physical and psychological health in children with DCD in the long run.

Associations of weather conditions with adolescents' daily physical activity, sedentary time, and sleep duration

Weather has been recognized as an environmental factor that affects daily activities. However, the effects of a humid subtropical climate on daily activity behavior are unclear. This study investigated the associations of weather conditions with physical activity (PA), sedentary time (ST), and sleep duration in a sample of 740 Hong Kong adolescents (mean age: 14.7 ± 1.6 years). The activPAL was used to assess the time spent during moderate to vigorous PA (MVPA), ST, and sleep. Weather data (e.g., temperature, relative humidity, rainfall amount, and sunlight duration) were obtained from the Hong Kong Observatory. Linear mixed models were constructed to examine the associations of weather conditions with the durations of MVPA, ST, and sleep on weekdays and weekend days, respectively. The analysis included valid data from 561 students (51.9% male). Among Hong Kong adolescents, a higher relative humidity was associated with reduced MVPA on weekdays and weekends, more ST on weekdays, and a longer sleep duration on weekends. A longer duration of sunlight induced less MVPA on weekends, but a longer sleep duration on weekdays. On weekends, higher temperatures correlated with increases in MVPA and ST but a decrease in sleep duration. Rainfall correlated inversely with sleep duration and positively with ST on weekdays. The associations of rainfall with MVPA exhibited opposite trends on weekdays and weekends. In summary, the relationships between weather conditions and daily activities exhibited day-type patterns. The findings suggest that environment-controlled indoor PA should be recommended during weather conditions of high relative humidity and higher temperatures.

Age-specific affective responses and self-efficacy to acute high-intensity interval training and continuous exercise in insufficiently active young and middle-aged men

Background/objective

High-intensity interval training (HIIT) has been recognized as an emerging trend in public health promotion, but its age-specific differences in psycho-perceptual responses have yet to be investigated. This study compared the psycho-perceptual responses after a single session of HIIT versus moderate-intensity continuous exercise (MICE) and vigorous-intensity continuous exercise (VICE) in twelve young and twelve middle-aged insufficiently active males respectively.

Methods

Using a randomized cross-over design, participants undertook three main trials consisting of: HIIT (10 x 1-min run at 100% VO_2max interspersed with 1-min active recovery), MICE (40-min run at 65% VO_2max) and VICE (20-min run at 80% VO_2max). Affective responses, self-efficacy and exercise preference were assessed for each trial.

Results

Both HIIT and VICE showed more positive in-task affective responses than MICE in young adults, while middle-aged adults reported more positive responses in both HIIT and MICE than in VICE. However, middle-aged adults displayed significantly lower exercise task self-efficacy scores towards HIIT (42.7 ± 25.3) and VICE (49.2 ± 23.9) than MICE (63.4 ± 18.3, both P < 0.01). Additionally, only 17% of participants in the middle-aged group reported a preference to engage in HIIT as opposed to either MICE (50%) and VICE (33%).

Conclusion

Our finding revealed distinct affective and self-efficacy responses to acute HIIT versus both MICE and VICE in the two age groups which assists in our understanding of how individuals in various age populations perceive HIIT. This information will assist in the design and implementation of effective exercise programs for public health, especially for insufficiently active individuals.

Effects of whey protein in carbohydrate-electrolyte drinks on post-exercise rehydration

The purpose of this study was to examine the effects of different amounts of whey protein in carbohydrate-electrolyte (CE) drinks on post-exercise rehydration. Ten males completed 5 trials in a randomised cross-over design. A 4-h recovery was applied after a 60-min run at 65% VO_2peak in each trial. During recovery, the participants ingested a high-carbohydrate CE drink (CE-H), a low-carbohydrate CE drink (CE-L), a high-whey-protein (33 g·L^-1) CE drink (CW-H), a medium-whey-protein (22 g·L^-1) CE drink (CW-M) or a low-whey-protein (15 g·L^-1) CE drink (CW-L) in a volume equivalent to 150% of their body mass (BM) loss. The drinks were provided in six equal boluses and consumed by the participants within 150 min in each trial. After exercise, a BM loss of 2.15% ± 0.05% was achieved. Urine production was less in the CW-M and CW-H trials during recovery, which induced a greater fluid retention in the CW-M (51.0% ± 5.7%) and CW-H (55.4% ± 3.8%) trials than in any other trial (p < .05). The plasma albumin content was higher in the CW-H trial than in the CE-H and CE-L trials at 2 h (p < .05) and 3 h (p < .01) during recovery. The aldosterone concentration was lower in the CE-H trial than in the CW-M and CW-H trials after recovery (p < .05). It is concluded that the rehydration was improved when whey protein was co-ingested with CE drinks during a 4-h recovery after a 60-min run. However, this additive effect was only observed when whey protein concentration was at least 22 g·L^-1 in the current study.

Effect of pre-exercise carbohydrate diets with high vs low glycemic index on exercise performance: a meta-analysis

Context

Although pre-exercise consumption of a low-glycemic-index (LGI) carbohydrate meal is generally recommended, the findings regarding subsequent exercise performance are inconsistent.

Objective

This meta-analytic study was conducted to determine whether a pre-exercise LGI carbohydrate meal leads to greater endurance performance than a pre-exercise high-glycemic-index (HGI) meal.

Data sources

The following electronic databases were searched until April 2016: MEDLINE, SPORTDiscus, Web of Science, and Cochrane Central Register of Controlled Trials. The reference lists of selected articles were searched manually.

Study selection

Randomized controlled or crossover trials comparing the effects of LGI and HGI pre-exercise carbohydrate meals on subsequent exercise performance of healthy participants were included.

Data extraction

The Jadad scale was used to assess the methodological quality of the included studies. A fixed-effects model was used to evaluate overall and subgroup estimates.

Results

In total, 15 eligible studies from 727 articles were included in this meta-analysis. All included studies were of low research quality. The synthesized effect size ( d  = 0.42, z  = 3.40, P  = 0.001) indicated that the endurance performance following an LGI meal was superior to that following an HGI meal. Subgroup analyses demonstrated that the treatment effect did not vary across outcome measures (exercise to exhaustion, time trial, and work output) or athletic status (trained or recreational participants).

Conclusions

Weak evidence supports the claim that endurance performance following a pre-exercise LGI meal is superior to that following a pre-exercise HGI meal. Further high-quality research in this area is warranted.

Isotemporal Substitution Analysis for Sedentary Behavior and Body Mass Index

PURPOSE

This study examined the prospective associations of reallocating time spent in different types of sedentary behavior, physical activity, and sleep with body mass index (BMI) in children using isotemporal substitution analysis.

METHODS

Chinese children in grades 1-3 were recruited to a cohort study in 2009 and were followed up over a 2-yr period. Reports were gathered from the parents on children's sedentary behavior, sleep duration, and sociodemographic variables. The reported sedentary behavior types were then grouped into three categories: screen time (e.g., watching TV), academic-related activities (e.g., doing homework), and other sedentary behaviors (e.g., sitting and talking). Moderate-to-vigorous physical activity (MVPA) and light-intensity physical activity were assessed by ActiGraph accelerometry (ActiGraph, Pensacola, FL). Isotemporal substitution models were performed to examine the effects of time allocation on BMI.

RESULTS

A total of 672 children (359 boys, mean age at recruitment = 7.6 yr) who had provided valid accelerometer data for at least one assessment time point were included in the analysis. Controlling for covariates and total behavior time, isotemporal substitution models indicated that the displacement of 30 min·d of other sedentary behaviors with equal amounts of screen time (B = 0.12; 95% confidence interval, 0.04-0.20) or academic-related activities (B = 0.13; 95% confidence interval, 0.04-0.21) was associated with higher BMI. Reallocating 30 min·d of MVPA with each of the sedentary behavior variables resulted in increased BMI.

CONCLUSIONS

The substitution of screen time or academic-related activities with other sedentary behaviors or MVPA was associated with lower BMI in Chinese children.

Children with Physical Disabilities at School and Home: Physical Activity and Contextual Characteristics

The purpose of this study was to assess the physical activity (PA) of children with physical disabilities (PD) in school and home settings and to simultaneously examine selected contextual characteristics in relation to PA in those settings. Children with PD (N = 35; Mean age = 15.67 ± 4.30 years; 26 boys) were systematically observed using BEACHES (Behaviors of Eating and Activity for Children’s Health: Evaluation System) at school (before school, recess, lunch break, after class) and at home (before dinner) during four normal school days. The children spent most of their time in all five settings being physically inactive, but had slightly more PA during recess and lunch break periods. Hierarchical multiple regression revealed that selected contextual characteristics explained 18.9–56.0% (p < 0.01) of the variance predicting moderate-to-vigorous physical activity (MVPA) after controlling for demographic variables. Prompts to be active were positively associated with MVPA at school and the presence of fathers and fathers being motivators at home. This study highlights how little PA that children with PD receive and identifies the importance of the provision of prompts for PA at both school and home with this special population.

Post-exercise appetite was affected by fructose content but not glycemic index of pre-exercise meals

The purpose of this study was to investigate whether both glycemic index (GI) and breakfast fructose content affect appetite during the postprandial period and recovery period after 1 hr of brisk walking. Ten healthy young men (age: 21.7 ± 1.5 y, body mass index: 20.9 ± 1.1 kg∙m(-2), VO2max: 53.7 ± 3.7 mL∙kg(-1)∙min(-1)) completed 1 hr of brisk walking at 46% VO2max 2 hr after eating one of three isocaloric breakfasts: a low-GI breakfast not including fructose content (LGI), a low-GI breakfast including fructose beverage (LGIF) and a high-GI breakfast (HGI). All breakfasts provided 1.0 g∙kg(-1) body weight carbohydrates, and the calculated GI values for the three breakfasts were 41, 39, and 72, respectively. In the LGIF and HGI trials, approximately 25% of participants' energy was derived from either fructose or glucose beverage. Appetite scores were measured every 30 min during the 2-hr postprandial period and 1-hr recovery period. During the postprandial period, the incremental areas under the blood response curve values of glucose and insulin were higher in the HGI trial, compared with those in the LGI and LGIF trials. At 30 and 60 min during the recovery period, the appetite scores were lower in the LGIF trial than those in the LGI and HGI trials. No differences were observed between the LGI and HGI trials. Breakfast fructose content, rather than GI, seems to affect appetite during the recovery period after 1 hr of brisk walking.

Effects of protein addition to carbohydrate-electrolyte solutions on postexercise rehydration

Background/Objective

This study aimed to examine the effects of the addition of whey or casein protein, the two major proteins in milk, to carbohydrate-electrolyte (CE) solutions on postexercise rehydration.

Methods

Ten young men aged 20.7 ± 1.4 years with an average VO_2max of 60.7 mL/kg/min ran for 60 minutes at 65% VO_2max on three occasions followed by 4 hours' recovery. During recovery, the participants consumed either CE solution with 66 g/L carbohydrate (CHO), or CE plus whey protein solution (CW trial, 44 g/L CHO, 22 g/L whey), or CE plus casein protein solution (CC trial, 44 g/L CHO, 22 g/L casein); the solutions were matched for energy and electrolyte content.

Results

The participants lost 2.36 ± 0.32% of their pre-exercise body weight after the exercise. Total urine output after recovery was greater in the CE and CC trials than CW trial (CE vs. CW vs. CC: 1184 ± 378 mL vs. 1005 ± 214 mL vs. 1256 ± 413 mL; p < 0.05). Fluid retention after ingestion of CW solution was greater than CE and CC solutions (CE vs. CW vs. CC: 46.9 ± 16.5% vs. 54.9 ± 9.2% vs. 45.8 ± 17.3%; p < 0.05). Lower urine specific gravity and urine osmolality were observed by the end of recovery in the CE trial compared with CW trial (p < 0.05). No difference was found in the changes in plasma volume in all trials.

Conclusion

These results suggest that during the 4 hours' recovery after a 60-minute run, the CW solution was more effective for rehydration compared with the CE or CC solution.

Carbohydrate electrolyte solutions enhance endurance capacity in active females

The purpose of the present study was to investigate the effects of supplementation with a carbohydrate-electrolyte solution (CES) in active females during a prolonged session of submaximal running to exhaustion. Eight healthy active females volunteered to perform a session of open-ended running to exhaustion at 70% of their maximal oxygen consumption on a treadmill during the follicular phase of their menstrual cycle on two occasions. During each run, the subjects consumed either 3mL·kg⁻¹ body mass of a 6% CES or a placebo drink (PL) every 20 min during exercise. The trials were administered in a randomized double-blind, cross-over design. During the run, the subjects ingested similar volumes of fluid in two trials (CES: 644 ± 75 mL vs. PL: 593 ± 66 mL, p > 0.05). The time to exhaustion was 16% longer during the CES trial (106.2 ± 9.4 min) than during the PL trial (91.6 ± 5.9 min) (p < 0.05). At 45 min during exercise, the plasma glucose concentration in the CES trial was higher than that in PL trial. No differences were observed in the plasma lactate level, respiratory exchange ratio, heart rate, perceived rate of exertion, sensation of thirst, or abdominal discomfort between the two trials (p > 0.05). The results of the present study confirm that CES supplementation improves the moderate intensity endurance capacity of active females during the follicular phases of the menstrual cycle. However, the exogenous oxidation of carbohydrate does not seem to explain the improved capacity after CES supplementation.

Effect of the glycemic index of pre-exercise snack bars on substrate utilization during subsequent exercise

PURPOSE

To investigate the effect of the glycemic index (GI) of pre-exercise snack bars on substrate utilization during subsequent moderate intensity exercise.

METHODS

Fourteen male participants (Age: 27 ± 5 yr; BMI: 22.5 ± 2.7 kg m(-2); [Formula: see text]: 48.7 ± 6.1 mL kg(-1 )min(-1)) completed two trials in a randomized and counterbalanced crossover design. Two iso-caloric snack bars with different GI values (20, LGI versus 68, HGI) were provided to the participants. Ninety minutes later, all participants completed 45 minutes of ergometer cycling at 65% [Formula: see text]. Substrate utilization was measured using indirect calorimetry.

RESULTS

During exercise, higher fat oxidation and lower carbohydrate (CHO) oxidation were observed in the LGI trial (LGI versus HGI: CHO, 87.3 ± 20.1 versus 99.2 ± 19.0 g, p < 0.05; Fat, 15.0 ± 5.8 versus 9.7 ± 7.0 g, p < 0.05).

CONCLUSION

Compared with an iso-caloric HGI snack bar, pre-exercise LGI snack bar consumption may facilitate a shift of substrate utilization from CHO to fat during subsequent moderate intensity exercise.