Effects of exercise intensity and nutrition advice on myocardial function in obese children and adolescents: a multicentre randomised controlled trial study protocol

Feasibility and efficacy of adding high-intensity interval training to a multidisciplinary lifestyle intervention in children with obesity-a randomized controlled trial

BACKGROUND

Multidisciplinary lifestyle interventions for children with obesity in Denmark often include recommendations regarding physical activity, but no structured exercise program. We hypothesized that adding high-intensity interval training (HIIT) to a multidisciplinary lifestyle intervention would improve BMI z-score (primary outcome), waist circumference, blood pressure, and health-related quality of life (HRQOL).

METHODS

This randomized controlled trial included 173 children and adolescents with obesity. Participants were allocated to 12-months lifestyle intervention (N = 83), or 12-month lifestyle intervention accompanied by a 12-week HIIT program (N = 90). HIIT consisted of three weekly sessions and included activities eliciting intensities >85% of maximal heart rate.

RESULTS

Attendance rate for the 3-months HIIT intervention was 68.0 ± 23.2%. Dropout was lower in HIIT compared to control at three months (7.8% vs. 20.5%) and 12 months (26.5% vs 48.2%). Changes in BMI z-score did not differ between HIIT and control at 3 months (Mean Difference (MD): 0.01, 95% confidence interval (CI): -0.09; 0.12, P = 0.82) or 12 months (MD: 0.06, CI: -0.07;0.19, P = 0.34). Across randomization, BMI z-score was reduced by 0.11 (CI: 0.17; 0.06, P < 0.01) at 3 months and 0.20 (CI: 0.26;0.14, P < 0.01) at 12 months. At 3 months, HIIT experienced a greater increase in HRQOL of 2.73 (CI: 0.01;5.44, P = 0.05) in PedsQL Child total-score and 3.85 (CI: 0.96; 6.74, P < 0.01) in psychosocial health-score compared to control. At 12 months, PedsQL Child physical-score was reduced by 6.89 (CI: 10.97; 2.83, P < 0.01) in HIIT compared to control. No group differences or changes over time were found for waist circumference or blood pressure.

CONCLUSION

Adding a 12-week HIIT program did not further augment the positive effects of a 12-month lifestyle intervention on BMI z-score. Adding HIIT improved HRQOL after 3 months, but reduced HRQOL at 12 months. Implementation of HIIT in community-based settings was feasible and showed positive effects on adherence to the lifestyle intervention.

School-based high-intensity interval exercise program in children with overweight induce a greater improvements in body composition and physical fitness than moderate-intensity continuous exercise

BACKGROUND

High-intensity interval running exercise (HIIE) is emerging as a time-efficient exercise modality for improving body composition and fitness in comparison with moderate-intensity continuous aerobic exercise (MICE); however, existing evidence is still unclear in children with overweight and thus we compared the effects of HIIE and MICE on body composition, muscular, and cardiorespiratory fitness in children with overweight.

METHODS

In this randomized study, 40 male children with overweight aged 7-10 years were divided into an 8-week exercise regime: (1) HIIE group [n = 20; 2 sets of 15 × 20s at 85-95% maximal aerobic speed (MAS) separated by 15 × 20s recovery at 50% MAS, 3 days per week] and (2) MICE group [n = 20; 30 min at 60-70% MAS, 3 days per week]. Body composition, muscular and cardiorespiratory fitness were assessed before and after the 8-week intervention at similar times and conditions of the day.

RESULTS

Following the 8-week HIIE protocol, weight, BMI, and fat mass decreased significantly (weight: - 1.4% vs. 0.2%, p < 0.05; BMI: - 3.1% vs. - 0.7%, p < 0.05; fat mass: - 7.7% vs. - 1.6%, p < 0.01) as compared with MICE; while the VO2peak and MAS increased significantly in both groups, the increase in HIIE group was significantly greater than that of MICE group (VO2peak: 10.3% vs. 3.5%, p < 0.01; MAS:7.7% vs. 4.5%, p < 0.05). Although significant improvements in muscular fitness were observed in HIIE and MICE groups [counter movement jump (CMJ): 7.8% vs. 5.4%; sprinting ability: - 3.7% vs. - 1.7%], no significant differences were seen between them (p > 0.05).

CONCLUSION

Our findings suggested that school-based HIIE intervention was highly in improving body composition and cardiorespiratory fitness of children with overweight than the MICE regime; however, MICE still provided improvements over time that were just not to the same magnitude of HIIE.

Effects of school-based high-intensity interval training on body composition, cardiorespiratory fitness and cardiometabolic markers in adolescent boys with obesity: a randomized controlled trial

Background

With accumulating evidence suggesting that CVD has its origins in childhood obesity. The purpose of this study was to determine the effect of a real-world school-based high-intensity interval training intervention on body composition, cardiorespiratory fitness and cardiometabolic markers in obese boys aged 10 to 13 years.

Methods

Forty-five adolescent boys with obesity (age = 11.2 ± 0.7 years, BMI = 24.2 ± 1.0 kg/m²), were randomized to high-intensity interval training group (HIIT, n = 15), moderate-intensity continuous training group (MICT, n = 15), or a control group (CON, n = 15). The intervention groups performed three weekly exercise sessions over 12 weeks. HIIT group performed two sets of eight bouts of 15 s run at high-intensity [90 ~ 100% maximal aerobic speed (MAS)] separated by eight bouts of 15 s recovery run at low-intensity (50% MAS), MICT group performed 30 min run at moderate intensity (60 ~ 70% MAS) and CON group were instructed to continue their normal behaviors. All participants had indices of body composition, cardiorespiratory fitness (CRF) and cardiometabolic markers measured at baseline and post-intervention. Statistical differences between and within groups were determined by use of two-way analysis of variance (ANOVA) with repeated measures.

Results

Following the school-based training program, BMI and body fat mass decreased (BMI: − 1.8 kg/m² vs. – 1.2 kg/m², P < 0.01; FM: − 1.6 kg, P < 0.05 vs. -3.7 kg, P < 0.01) in HIIT and MICT group, but there was no significant difference between the two interventions; \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{\mathrm{V}}{\mathrm{O}}_{2\mathrm{peak}}$$\end{document}V˙O2peak both increased significantly in two intervention groups, and the increment of HIIT group was significantly greater than that of MICT (6.1 mL/kg/min vs. 3.8 mL/kg/min, P < 0.01), Visceral adipose tissue was significant decrease in HIIT group (− 53 g vs. -17 g, P < 0.01) whilst the MICT group experienced a significant decrease in body fat percentage (− 3.1 ± 1.0 kg, P < 0.01), but there were no significant difference between the two interventions. Low-density lipoprotein cholesterol decreased only in HIIT group (− 17.2%, P < 0.05). Significant decrease in the usual index of insulin resistance (HOMA-IR) occurred in HIIT and MICT groups (− 27.3 and − 28.6%, respectively; P < 0.05).

Conclusions

Our results demonstrated that high-intensity interval training based on running can be used to improve the physical health of obese adolescents in school. Further investigations involving a larger cohort of participants, taken from different schools, is recommended.

Trial registration

title Effect of High Intensity Interval Training on Obese Children and Adolescents, time 16/12/2017, IDChiCTR-IOR-17013992, websitehttp://www.chictr.org.cn

Comparison of two methods of cardiopulmonary exercise testing for assessing physical fitness in children and adolescents with extreme obesity

It is well-known that children and adolescents with obesity have increased over recent decades which in turn carries greater risk of co-morbidities and poses a preventive as well as a therapeutic challenge. Currently, there are limited recommendations available on proven methods for recording physical fitness in children and adolescents presenting with extreme obesity. In this study, twenty participants, aged 12-17 years, with a body mass index (BMI) above the 99.5th percentile, were comparatively assessed, using a correlation between their physical fitness on a bicycle (BC) and treadmill (TM) cardiopulmonary exercise testing (CPET) with a lactate diagnostic. The results of the BC and the TM were as follows: maximum heart rate (HR_max) 186.4 ± 8.6 beats per minute (bpm) vs. 190.8 ± 8.8 bpm, peak oxygen consumption (VO₂peak/kg) 23.5 ± 2.9 ml/min/kg vs. 25.4 ± 3.1 ml/min/kg, and maximum lactate (La_max) 6.4 ± 1.6 mmol/l vs. 5.6 ± 1.4 mmol/l. The values of HR_max and VO₂peak/kg were significantly higher for adolescents tested on the TM. However, no significant difference was observed in either La_max values or between the genders.    Conclusions: The higher values of HR_max and VO₂peak/kg could be attributed to the activation of a higher percentage of muscle mass on the TM. Lower La_max values on the TM suggest maximum physical exertion was not achieved. This could be due to the extreme body weight carried by the participants. Both the BC and the TM CPET could be used for assessing physical fitness in children and adolescents with extreme obesity but should not be used interchangeably. What is Known: • Currently, there are only limited recommendations available on proven methods for recording physical fitness in children and adolescents with extreme obesity available. What is New: • Cardiopulmonary exercise testing with maximum physical exertion has been shown to be feasible in children and adolescents with extreme obesity. The results obtained from this study demonstrated that both a bicycle and a treadmill can be effectively used for assessing the physical fitness levels in children and adolescents with extreme obesity.

High-intensity interval training in high-school physical education classes: Study protocol for a randomized controlled trial

Background

School and Physical Education classes (PEC) are privileged spaces, promoters of positive changes for the rest of life. High-Intensity Interval Training (HIIT) is presented as a time-efficient alternative to aerobic training, as it leverages the number of exercise participants, resulting in improvements in health outcomes. Despite the widespread interest in the advantages that the HIIT methodology reveals, there is a lack of randomized controlled studies investigating the impact on adolescents, mainly adressing adolescents’ environment, such as schools. This study aims to evaluate the utility of a HIIT program integrated into high-school PEC, as a strategy that allows students to improve their Physical Fitness, Physical Activity (PA) level, and Motivation for Exercise.

Methods

This study is a two-arm randomized controlled trial design with adolescents from the 10th to 12th grades (15–17 years). The trial will aim to recruit 300 students from 1 secondary school. The HIIT sessions will be applied in the first 10–15 min of each PEC, twice a week, for 16 weeks, ranged from 14 to 20 all-out bouts intervals, adopting a 2:1 work to rest ratio. A cut-point of ≥ 90% of maximal heart rate will be a criterion for satisfactory compliance to high-intensity exercise. A rated perceived exertion scale will be measured in each exercise session to estimate effort, fatigue, and training load. The control group will continue the usual programmed PEC. Study outcomes will be measured at baseline and after the HIIT program. Cardiorespiratory fitness is the primary outcome. Secondary outcomes include: muscular fitness, PA and motivation for exercise.

Discussion

HIIT protocols presents wide applicability in PEC and great adaptation to the facilities. The authors aim to provide novel HIIT protocols for schools.

Impact of Lifestyles (Diet and Exercise) on Vascular Health: Oxidative Stress and Endothelial Function

Healthy lifestyle and diet are associated with significant reduction in risk of obesity, type 2 diabetes, and cardiovascular diseases. Oxidative stress and the imbalance between prooxidants and antioxidants are linked to cardiovascular and metabolic diseases. Changes in antioxidant capacity of the body may lead to oxidative stress and vascular dysfunction. Diet is an important source of antioxidants, while exercise offers many health benefits as well. Recent findings have evidenced that diet and physical factors are correlated to oxidative stress. Diet and physical factors have debatable roles in modulating oxidative stress and effects on the endothelium. Since endothelium and oxidative stress play critical roles in cardiovascular and metabolic diseases, dietary and physical factors could have significant implications on prevention of the diseases. This review is aimed at summarizing the current knowledge on the impact of diet manipulation and physical factors on endothelium and oxidative stress, focusing on cardiovascular and metabolic diseases. We discuss the friend-and-foe role of dietary modification (including different diet styles, calorie restriction, and nutrient supplementation) on endothelium and oxidative stress, as well as the potential benefits and concerns of physical activity and exercise on endothelium and oxidative stress. A fine balance between oxidative stress and antioxidants is important for normal functions in the cells and interfering with this balance may lead to unfavorable effects. Further studies are needed to identify the best diet composition and exercise intensity.

Emerging functions of adipokines in linking the development of obesity and cardiovascular diseases

Increasing evidence shows that obesity is the critical factor in shaping cardio-metabolic phenotypes. However, the pathogenic mechanisms remain incompletely clarified. According to the published reports, adipose tissue communicates with several diverse organs, such as heart, lungs, and kidneys through the secretion of various cytokines named adipokines. The adipocytes isolated from obese mice or humans are dysfunctional with aberrant production of pro-inflammatory adipokines, which subsequently induce both acute and chronic inflammatory reaction and facilitate the process of cardio-metabolic disorder complications. Furthermore, the microenvironment within adipose tissue under obese status also influence the secretion of adipokines. Recently, given that several important adipokines have been completely researched and causally involved in various diseases, we could make a conclusion that adipokines play an essential role in modulating the development of cardio-metabolic disorder diseases, whereas several novel adipokines continue to be explored and elucidated. In the present review, we summarized the current knowledge of the microenvironment of adipose tissue and the published mechanisms whereby adipocytes affects obesity and cardiovascular diseases. On the other hand, we also provide the evidence to elucidate the functions of adipokines in controlling and regulating the inflammatory reactions which contribute to obesity and cardiovascular disease.

Preventive Effects of Different Aerobic Exercise Intensities on the Decline of Cognitive Function in High-Fat Diet-Induced Obese Growing Mice

Background and Objectives: The purpose of this study was to elucidate the effects of different exercise intensities in preventing the decline of cognitive function and lipolysis associated with a high-fat diet-induced obesity in growing mice. Material and Methods: Forty male C57BL/6 mice, aged 4 weeks, were divided into the normal diet (CO, n = 10) and high-fat diet (HF, n = 30) groups to induce obesity for 8 weeks. Subsequently, the HF group was subdivided equally into the HF, HF + low-intensity training (HFLT), and HF + high-intensity training (HFHT) groups, and mice were subjected to treadmill training for 8 weeks. Results: Following the 8-week training intervention, body weight and fat mass were significantly lower in the training groups than in the HF group (p < 0.05). Adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), and monoglyceride lipase levels were significantly higher in the training groups than in the HF group (p < 0.05), and the ATGL and HSL levels were significantly higher in the HFHT group than in the HFLT group (p < 0.05). The Y-maze test showed that the training groups had a higher number of total entries and percent alternation than the HF group (p < 0.05). Hippocampal nerve growth factor, brain-derived neurotrophic factor, and neurotrophin-3 levels were significantly higher in the training group than in the HF group (p < 0.05). However, there was no significant difference according to the exercise intensity among the groups. Conclusions: The results of this study suggested that low-intensity exercise is as effective as a high-intensity exercise in preventing the decline of cognitive function and lipolysis, and far more effective in terms of an expected efficiency of workload and prevention of side effects.

Multidisciplinary lifestyle intervention in children and adolescents - results of the project GRIT (Growth, Resilience, Insights, Thrive) pilot study

BACKGROUND

During childhood and adolescence leading behavioural risk factors for the development of cardiometabolic diseases include poor diet quality and sedentary lifestyle. The aim of this study was to determine the feasibility and effect of a real-world group-based multidisciplinary intervention on cardiorespiratory fitness, diet quality and self-concept in sedentary children and adolescents aged 9 to 15 years.

METHODS

Project GRIT (Growth, Resilience, Insights, Thrive) was a pilot single-arm intervention study. The 12-week intervention involved up to three outdoor High Intensity Interval Training (HIIT) running sessions per week, five healthy eating education or cooking demonstration sessions, and one mindful eating and Emotional Freedom Technique psychology session. Outcome measures at baseline and 12-week follow-up included maximal graded cardiorespiratory testing, the Australian Child and Adolescent Eating Survey, and Piers-Harris 2 children's self-concept scale. Paired samples t-test or Wilcoxon signed-rank test were used to compare baseline and follow-up outcome measures in study completers only.

RESULTS

Of the 38 recruited participants (median age 11.4 years, 53% male), 24 (63%) completed the 12-week intervention. Dropouts had significantly higher diet quality at baseline than completers. Completers attended a median 58 (IQR 55-75) % of the 33 exercise sessions, 60 (IQR 40-95) % of the dietary sessions, and 42% attended the psychology session. No serious adverse events were reported. Absolute VO₂peak at 12 weeks changed by 96.2 ± 239.4 mL/min (p = 0.06). As a percentage contribution to energy intake, participants increased their intake of healthy core foods by 6.0 ± 11.1% (p = 0.02) and reduced median intake of confectionary (- 2.0 [IQR 0.0-3.0] %, p = 0.003) and baked products (- 1.0 [IQR 0.0-5.0] %, p = 0.02). Participants significantly improved self-concept with an increase in average T-Score for the total scale by 2.8 ± 5.3 (p = 0.02) and the 'physical appearance and attributes' domain scale by median 4.0 [IQR 0.5-4.0] (p = 0.02).

CONCLUSIONS

The 12-week group-based multidisciplinary lifestyle intervention for children and adolescents improved diet quality and self-concept in study completers. Future practice and research should focus on providing sustainable multidisciplinary lifestyle interventions for children and adolescents aiming to improve long-term health and wellbeing.

TRIAL REGISTRATION

ANZCTR, ACTRN12618001249246. Registered 24 July 2019 - Retrospectively registered.

Effects of high-intensity interval training and nutrition advice on cardiometabolic markers and aerobic fitness in adolescent girls with obesity

The aim of the study was to compare the effects of high-intensity interval training (HIIT) and nutrition advice on cardiometabolic biomarkers, hormonal parameters, and cardiorespiratory fitness in adolescent girls with obesity. Adolescent girls with obesity (n = 44, aged 13-19 years) were randomized into a 12-week intervention as follows: (i) dietary advice and HIIT (n = 22), and (ii) dietary advice only (n = 22). The concentration of biomarkers of inflammation, biochemical and hormonal testing, oral glucose tolerance test, cardiorespiratory fitness, physical activity levels, and nutrition were assessed. After a 3-month intervention, the diet+HIIT group significantly increased insulin sensitivity index (-0.34 ± 1.52 vs. 1.05 ± 3.21; p = 0.001) and work load (0.6 ± 11.3 W vs. 14.6 ± 20.2 W; p = 0.024) and decreased glucose area under the curve (-0.29 ± 4.69 vs. -0.98 ± 4.06; p = 0.040), insulin area under the curve (-9.65 ± 117.9 vs. -98.7 ± 201.8; p = 0.003), and high-sensitivity C-reactive protein (hs-CRP) (0.12 ± 1.92 mg/L vs. -1.47 ± 3.67 mg/L; p = 0.039) in comparison with the diet group. Regarding within-group changes, both groups had significant improvements in body mass index (BMI), BMI-standard deviation score, body fat percentage, and systolic blood pressure. Positive impact on waist circumference, waist circumference/height ratio, diastolic blood pressure, hs-CRP, work load, maximal heart rate, and resting heart rate was observed only after the diet+HIIT intervention. No significant change was noted in peak oxygen uptake, lipid profile, and hormonal parameters between groups after intervention. Novelty HIIT and nutrition advice increased insulin sensitivity and decreased BMI, body fat, systolic blood pressure, and diastolic blood pressure. Nutrition advice decreased BMI, body fat, and systolic blood pressure in adolescent girls with obesity.

Accuracy of Longitudinal Assessment of Visceral Adipose Tissue by Dual-Energy X-Ray Absorptiometry in Children with Obesity

BACKGROUND

Increased visceral adipose tissue (VAT) is strongly associated with cardiometabolic risk factors. Accurate quantification of VAT is available through magnetic resonance imaging (MRI), which incurs a significant financial and time burden. We aimed to assess the accuracy of dual-energy X-ray absorptiometry- (DXA-) derived VAT (DXA-VAT) against a gold standard MRI protocol (MRI-VAT) in children with normal weight and obesity cross-sectionally, and over the course of a lifestyle intervention.

METHODOLOGY

MRI-VAT and DXA-VAT were quantified in 61 children (30 normal weight and 31 with obesity) at baseline. Children with obesity entered a three-month exercise and/or nutrition intervention after which VAT was reassessed. MRI- and DXA-VAT cross-sectional area, volume, and mass were quantified, and associations were calculated at baseline (n = 61) and pre-post intervention (n = 28, 3 participants dropped out). Method agreement was assessed through Bland-Altman analysis, linear regression, and Passing-Bablok regression.

RESULTS

At baseline, all DXA- and MRI-VAT outcomes were strongly associated (r = 0.90, P < 0.001). However, there were no significant associations between absolute or relative change in DXA- and MRI-VAT outcomes (r = 0.25-0.36, P > 0.05). DXA significantly overestimated VAT CSA (cross-sectional area), volume, and mass when compared with MRI (P < 0.001) at baseline. Significant proportional bias was observed for all DXA-VAT outcomes at baseline and for relative longitudinal changes in DXA-VAT.

CONCLUSIONS

Although DXA-VAT outcomes were strongly associated with MRI-VAT outcomes at baseline, estimates were subject to proportional bias in children with obesity and normal weight. DXA lacks validity for detecting changes in VAT among children with obesity. This trial is registered with NCT01991106.

Effect of High-Intensity Interval Training on Fitness, Fat Mass and Cardiometabolic Biomarkers in Children with Obesity: A Randomised Controlled Trial

BACKGROUND

Paediatric obesity significantly increases the risk of developing cardiometabolic diseases across the lifespan. Increasing cardiorespiratory fitness (CRF) could mitigate this risk. High-intensity interval training (HIIT) improves CRF in clinical adult populations but the evidence in paediatric obesity is inconsistent.

OBJECTIVES

The objectives of this study were to determine the efficacy of a 12-week, HIIT intervention for increasing CRF and reducing adiposity in children with obesity.

METHODS

Children with obesity (n = 99, 7-16 years old) were randomised into a 12-week intervention as follows: (1) HIIT [n = 33, 4 × 4-min bouts at 85-95% maximum heart rate (HR_max), interspersed with 3 min of active recovery at 50-70% HR_max, 3 times/week] and nutrition advice; (2) moderate-intensity continuous training (MICT) [n = 32, 44 min at 60-70% HR_max, 3 times/week] and nutrition advice; and (3) nutrition advice only (nutrition) [n = 34]. CRF was quantified through a maximal exercise test ([Formula: see text]) while adiposity was assessed using magnetic resonance imaging (MRI), dual-energy X-ray absorptiometry (DXA) and air-displacement plethysmography.

RESULTS

HIIT stimulated significant increases in relative [Formula: see text] compared with MICT (+3.6 mL/kg/min, 95% CI 1.1-6.0, P = 0.004) and the nutrition intervention (+5.4 mL/kg/min, 95% CI 2.9-7.9, P = 0.001). However, the intervention had no significant effect on visceral and subcutaneous adipose tissue, whole body composition or cardiometabolic biomarkers (P > 0.05).

CONCLUSION

A 12-week, HIIT intervention was highly effective in increasing cardiorespiratory fitness when compared with MICT and nutrition interventions. While there were no concomitant reductions in adiposity or blood biomarkers, the cardiometabolic health benefit conferred through increased CRF should be noted.

CLINICAL TRIALS REGISTRATION NUMBER

Clinicaltrials.gov; NCT01991106.

Evaluation of motor proficiency and adiponectin in adolescent students with attention deficit hyperactivity disorder after high-intensity intermittent training

Attention deficit hyperactivity disorder (ADHD) is a chronic condition with frequent comorbidities such as obesity, troubled relationships, low self-esteem, and difficulty in motor proficiency. This study aims to elucidate the effect of high-intensity intermittent training on motor proficiency, adiponectin, and insulin resistance in adolescent students with ADHD disorder. Fifty adolescent students of both genders with ADHD diagnosis participated and assigned into four experimental groups (each group with 15 girls and 10 boys students; two experimental and two control groups). High-intensity intermittent training was performed continuously 3 times a week for 6 weeks in experimental groups. Serum adiponectin level significantly increased in the experimental groups of both genders after 6 weeks intermittent training while insulin resistance levels were markedly decreased. Furthermore, motor proficiency score were significantly improved in the experimental groups of both genders. In addition gender had no significant impact on adiponectin, insulin resistance and motor proficiency rating. The findings of this study suggest that high intensity intermittent training improved physiological systems in ADHD population that leads to reduce risk factors for future development of comorbidities.

Effect of High Intensity Interval Training on Cardiac Function in Children with Obesity: A Randomised Controlled Trial

BACKGROUND

High intensity interval training (HIIT) confers superior cardiovascular health benefits to moderate intensity continuous training (MICT) in adults and may be efficacious for improving diminished cardiac function in obese children. The aim of this study was to compare the effects of HIIT, MICT and nutrition advice interventions on resting left ventricular (LV) peak systolic tissue velocity (S') in obese children.

METHODS

Ninety-nine obese children were randomised into one of three 12-week interventions, 1) HIIT [n = 33, 4 × 4 min bouts at 85-95% maximum heart rate (HR_max), 3 times/week] and nutrition advice, 2) MICT [n = 32, 44 min at 60-70% HR_max, 3 times/week] and nutrition advice, and 3) nutrition advice only (nutrition) [n = 34].

RESULTS

Twelve weeks of HIIT and MICT were equally efficacious, but superior to nutrition, for normalising resting LV S' in children with obesity (estimated mean difference 1.0 cm/s, 95% confidence interval 0.5 to 1.6 cm/s, P < 0.001; estimated mean difference 0.7 cm/s, 95% confidence interval 0.2 to 1.3 cm/s, P = 0.010, respectively).

CONCLUSIONS

Twelve weeks of HIIT and MICT were superior to nutrition advice only for improving resting LV systolic function in obese children.

Metabolism and Exercise During Youth-The Year That Was 2017

Two publications were selected because they are excellent representations of studies examining different ends of the exercise-sedentary behavior continuum in young people. The first study is an acute response study with 13 mixed-sex, mid to late adolescents presenting complete data from 4 different randomized experimental crossover conditions for analyses. Continuous glucose monitoring showed that interrupting prolonged continuous sitting with body-weight resistance exercises reduced the postprandial glucose concentration compared with a time-matched uninterrupted period of sitting. Furthermore, the effects of the breaks in sitting time were independent of the energy content of the standardized meals, but variations in the area under the glucose time curves expression were important. The second study adopted a chronic 12-week exercise training intervention design with a large sample of obese children and adolescents who were allocated randomly to high-intensity interval training (HIIT), moderate-intensity continuous training, or nutritional advice groups. HIIT was the most efficacious for improving cardiorespiratory fitness compared with the other interventions; however, cardiometabolic biomarkers and visceral/subcutaneous adipose tissue did not change meaningfully in any group over the 12 weeks. Attrition rates from both HIIT and moderate-intensity continuous training groups reduce the validity of the exercise training comparison, yet this still provides a solid platform for future research comparisons using HIIT in young people.

Diet, physical activity and behavioural interventions for the treatment of overweight or obese children from the age of 6 to 11 years

BACKGROUND

Child and adolescent overweight and obesity has increased globally, and can be associated with significant short- and long-term health consequences. This is an update of a Cochrane review published first in 2003, and updated previously in 2009. However, the update has now been split into six reviews addressing different childhood obesity treatments at different ages.

OBJECTIVES

To assess the effects of diet, physical activity and behavioural interventions (behaviour-changing interventions) for the treatment of overweight or obese children aged 6 to 11 years.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, LILACS as well as trial registers ClinicalTrials.gov and ICTRP Search Portal. We checked references of studies and systematic reviews. We did not apply any language restrictions. The date of the last search was July 2016 for all databases.

SELECTION CRITERIA

We selected randomised controlled trials (RCTs) of diet, physical activity, and behavioural interventions (behaviour-changing interventions) for treating overweight or obese children aged 6 to 11 years, with a minimum of six months' follow-up. We excluded interventions that specifically dealt with the treatment of eating disorders or type 2 diabetes, or included participants with a secondary or syndromic cause of obesity.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened references, extracted data, assessed risk of bias, and evaluated the quality of the evidence using the GRADE instrument. We contacted study authors for additional information. We carried out meta-analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 70 RCTs with a total of 8461 participants randomised to either the intervention or control groups. The number of participants per trial ranged from 16 to 686. Fifty-five trials compared a behaviour-changing intervention with no treatment/usual care control and 15 evaluated the effectiveness of adding an additional component to a behaviour-changing intervention. Sixty-four trials were parallel RCTs, and four were cluster RCTs. Sixty-four trials were multicomponent, two were diet only and four were physical activity only interventions. Ten trials had more than two arms. The overall quality of the evidence was low or very low and 62 trials had a high risk of bias for at least one criterion. Total duration of trials ranged from six months to three years. The median age of participants was 10 years old and the median BMI z score was 2.2.Primary analyses demonstrated that behaviour-changing interventions compared to no treatment/usual care control at longest follow-up reduced BMI, BMI z score and weight. Mean difference (MD) in BMI was -0.53 kg/m2 (95% confidence interval (CI) -0.82 to -0.24); P < 0.00001; 24 trials; 2785 participants; low-quality evidence. MD in BMI z score was -0.06 units (95% CI -0.10 to -0.02); P = 0.001; 37 trials; 4019 participants; low-quality evidence and MD in weight was -1.45 kg (95% CI -1.88 to -1.02); P < 0.00001; 17 trials; 1774 participants; low-quality evidence.Thirty-one trials reported on serious adverse events, with 29 trials reporting zero occurrences RR 0.57 (95% CI 0.17 to 1.93); P = 0.37; 4/2105 participants in the behaviour-changing intervention groups compared with 7/1991 participants in the comparator groups). Few trials reported health-related quality of life or behaviour change outcomes, and none of the analyses demonstrated a substantial difference in these outcomes between intervention and control. In two trials reporting on minutes per day of TV viewing, a small reduction of 6.6 minutes per day (95% CI -12.88 to -0.31), P = 0.04; 2 trials; 55 participants) was found in favour of the intervention. No trials reported on all-cause mortality, morbidity or socioeconomic effects, and few trials reported on participant views; none of which could be meta-analysed.As the meta-analyses revealed substantial heterogeneity, we conducted subgroup analyses to examine the impact of type of comparator, type of intervention, risk of attrition bias, setting, duration of post-intervention follow-up period, parental involvement and baseline BMI z score. No subgroup effects were shown for any of the subgroups on any of the outcomes. Some data indicated that a reduction in BMI immediately post-intervention was no longer evident at follow-up at less than six months, which has to be investigated in further trials.

AUTHORS' CONCLUSIONS

Multi-component behaviour-changing interventions that incorporate diet, physical activity and behaviour change may be beneficial in achieving small, short-term reductions in BMI, BMI z score and weight in children aged 6 to 11 years. The evidence suggests a very low occurrence of adverse events. The quality of the evidence was low or very low. The heterogeneity observed across all outcomes was not explained by subgrouping. Further research is required of behaviour-changing interventions in lower income countries and in children from different ethnic groups; also on the impact of behaviour-changing interventions on health-related quality of life and comorbidities. The sustainability of reduction in BMI/BMI z score and weight is a key consideration and there is a need for longer-term follow-up and further research on the most appropriate forms of post-intervention maintenance in order to ensure intervention benefits are sustained over the longer term.