Efficacy of Exercise Intervention for Weight Loss in Overweight and Obese Adolescents: Meta-Analysis and Implications

Perspectives on high-intensity interval exercise for health promotion in children and adolescents

Physical activity lowers future cardiovascular disease (CVD) risk; however, few children and adolescents achieve the recommended minimum amount of daily activity. Accordingly, there is virtue in identifying the efficacy of small volumes of high-intensity exercise for health benefits in children and adolescents for the primary prevention of CVD risk. The purpose of this narrative review is to provide a novel overview of the available literature concerning high-intensity interval-exercise (HIIE) interventions in children and adolescents. Specifically, the following areas are addressed: 1) outlining the health benefits observed following a single bout of HIIE, 2) reviewing the role of HIIE training in the management of pediatric obesity, and 3) discussing the effectiveness of school-based HIIE training. In total, 39 HIIE intervention studies were included in this review. Based upon the available data, a single bout of high-intensity exercise provides a potent stimulus for favorable, acute changes across a range of cardiometabolic outcomes that are often superior to a comparative bout of moderate-intensity exercise (14 studies reviewed). HIIE also promotes improvements in cardiorespiratory fitness and cardiometabolic health status in overweight and obese children and adolescents (10 studies reviewed) and when delivered in the school setting (15 studies reviewed). We thus conclude that high-intensity exercise is a feasible and potent method of improving a range of cardiometabolic outcomes in children and adolescents. However, further work is needed to optimize the delivery of HIIE interventions in terms of participant enjoyment and acceptability, to include a wider range of health outcomes, and to control for important confounding variables (eg, changes in diet and habitual physical activity). Finally, research into the application of HIIE training interventions to children and adolescents of different ages, sexes, pubertal status, and sociocultural backgrounds is required.

A multidisciplinary intervention programme for overweight and obese children in deprived areas

BACKGROUND

GPs can refer obese children living in deprived areas to multidisciplinary programmes for a weight loss intervention, though the effectiveness of these local initiatives targeted to this specific group is unknown.

OBJECTIVE

To evaluate the effectiveness of the Kids4Fit intervention in deprived areas on child's weight status.

METHODS

Design and setting: cohort study, including a waiting list control period. Subjects: children (N = 154) aged 6-12 years, who signed up for the Kids4Fit intervention programme, led by a dietitian, physiotherapist and child psychologist were included. Measurements of standardized body mass index (BMI-z) and waist circumference were taken at start of the waiting list period, at start and at the end of the intervention and after 52 weeks. Mixed model analyses (random effects models) were used, expressed in effect per week [β with 95% confidence interval (CI)], compared to the waiting list expectancy over the 52-week study period.

RESULTS

Mixed model analyses showed a non-significant trend towards a lower BMI-z up to 52 weeks after start of Kids4Fit (β: -0.0024; 95% CI: -0.0053; 0.0004), compared to the waiting list expectancy. A significantly lower waist circumference was found over time compared to the waiting list expectancy (β: -0.0558; 95% CI: -0.0950; -0.0166). No differences were found in lifestyle and health-related quality of life.

CONCLUSION

A local multidisciplinary intervention programme in deprived areas is effective in reducing waist circumference of obese children, compared to a waiting list expectancy, but no significant changes in lifestyle and quality of life were shown.

The prevalence, metabolic risk and effects of lifestyle intervention for metabolically healthy obesity: a systematic review and meta-analysis: A PRISMA-compliant article

BACKGROUND

We conducted a systematic review and meta-analysis to firstly obtain a reliable estimation of the prevalence of metabolically healthy obese (MHO) individuals in obesity, then assessed the risk of developing metabolic abnormalities (MA) among MHO individuals. At last, we evaluated the effects of traditional lifestyle interventions on metabolic level for MHO subjects.

METHODS

A systematic review and meta-analysis (PRISMA) guideline were conducted, and original studies were searched up to December 31, 2016. The prevalence of MHO in obesity from each study was pooled using random effects models. The relative risks (RRs) were pooled to determine the risk of developing MA for MHO compared with metabolically healthy normal-weight (MHNW) subjects. For the meta-analysis of intervention studies, the mean difference and standardized mean differences were both estimated for each metabolic parameter within each study, and then pooled using a random-effects model.

RESULTS

Overall, 40 population-based studies reported the prevalence of MHO in obesity, 12 cohort studies and 7 intervention studies were included in the meta-analysis. About 35.0% obese individuals were metabolically healthy in the obese subjects. There were dramatic differences in the prevalence among different areas. However, 0.49 (95% confidence intervals [CI]: 0.38 to 0.60) of the MHO individuals would develop one or more MA within 10 years. Compared with MHNW subjects, the MHO subjects presented higher risk of incident MA (pooled RR = 1.80, 95%CI: 1.53-2.11). Following intervention, there was certain and significant improvement of metabolic state for metabolically abnormal obesity (MAO) subjects. Only diastolic blood pressure had reduced for MHO individuals after intervention.

CONCLUSIONS

Almost one-third of the obese individuals are in metabolic health. However, they are still at higher risk of advancing to unhealthy state. Therefore, it is still needed to advise MHO individuals to maintain or adopt a healthy lifestyle, so as to counterbalance the adverse effects of obesity.

Changes in physical fitness and body composition according to the physical activities of Korean adolescents

This study comparatively analyzed obesity, lean balance, and physical fitness related to growth and development in female middle school students to investigate the importance of regular physical activity on body composition and physical fitness in adolescence. The subjects were 31 elementary school students in grades 5–6 in Seoul, consisting of 16 students in the regularly active group and 15 students in the inactive group. Body composition and physical fitness factors were measured. Height, weight, body mass index (BMI), fat mass, and fat-free mass were measured using Inbody 3.0. Physical fitness factors such as muscle strength (grip strength), muscle endurance (situps), flexibility (body flexion), agility (side stepping), and lean balance (balancing with eyes closed), were measured as described herein. The results of comparing the two groups’ obesity-related body composition, the weight (P<0.001), body fat mass (P<0.001), BMI (P<0.002), and % body fat (P<0.033) were significantly higher in the inactive group compared to the physically active group. Comparison of lean balance was there was a significant difference in muscle mass between the left and right Arm (P<0.001), left and right leg (P<0.002) in the inactive group. comparing physical fitness between groups was trunk flexion (P<0.001) and side stepping (P<0.001) were higher in the physically active than the inactive group. This study found significant differences in weight, body fat, BMI, flexibility, and side stepping between the physically active and inactive groups, which may negatively affect health indicators related to adolescents’ growth, development, and obesity. Therefore, attempts to promote physical activity in growing adolescents are crucial.

Metabolic effects of resistance or high-intensity interval training among glycemic control-nonresponsive children with insulin resistance

BACKGROUND

Little evidence exists on which variables of body composition or muscular strength mediates more glucose control improvements taking into account inter-individual metabolic variability to different modes of exercise training.

OBJECTIVE

We examined 'mediators' to the effects of 6-weeks of resistance training (RT) or high-intensity interval training (HIT) on glucose control parameters in physically inactive schoolchildren with insulin resistance (IR). Second, we also determined both training-induce changes and the prevalence of responders (R) and non-responders (NR) to decrease the IR level.

METHODS

Fifty-six physically inactive children diagnosed with IR followed a RT or supervised HIT program for 6 weeks. Participants were classified based on ΔHOMA-IR into glycemic control R (decrease in homeostasis model assessment-IR (HOMA-IR) <3.0 after intervention) and NRs (no changes or values HOMA-IR⩾3.0 after intervention). The primary outcome was HOMA-IR associated with their mediators; second, the training-induced changes to glucose control parameters; and third the report of R and NR to improve body composition, cardiovascular, metabolic and performance variables.

RESULTS

Mediation analysis revealed that improvements (decreases) in abdominal fat by the waist circumference can explain more the effects (decreases) of HOMA-IR in physically inactive schoolchildren under RT or HIT regimes. The same analysis showed that increased one-maximum repetition leg-extension was correlated with the change in HOMA-IR (β=-0.058; P=0.049). Furthermore, a change in the waist circumference fully mediated the dose-response relationship between changes in the leg-extension strength and HOMA-IR (β'=-0.004; P=0.178). RT or HIT were associated with significant improvements in body composition, muscular strength, blood pressure and cardiometabolic parameters irrespective of improvement in glycemic control response. Both glucose control RT-R and HIT-R (respectively), had significant improvements in mean HOMA-IR, mean muscular strength leg-extension and mean measures of adiposity.

CONCLUSIONS

The improvements in the lower body strength and the decreases in waist circumference can explain more the effects of the improvements in glucose control of IR schoolchildren in R group after 6 weeks of RT or HIT, showing both regimes similar effects on body composition or muscular strength independent of interindividual metabolic response variability.

A Blended Web-Based Gaming Intervention on Changes in Physical Activity for Overweight and Obese Employees: Influence and Usage in an Experimental Pilot Study

Background

Addressing the obesity epidemic requires the development of effective interventions aimed at increasing physical activity (PA). eHealth interventions with the use of accelerometers and gaming elements, such as rewarding or social bonding, seem promising. These eHealth elements, blended with face-to-face contacts, have the potential to help people adopt and maintain a physically active lifestyle.

Objective

The aim of this study was to assess the influence and usage of a blended Web-based gaming intervention on PA, body mass index (BMI), and waist circumference among overweight and obese employees.

Methods

In an uncontrolled before-after study, we observed 52 health care employees with BMI more than 25 kg/m², who were recruited via the company’s intranet and who voluntarily participated in a 23-week Web-based gaming intervention, supplemented (blended) with non-eHealth components. These non-eHealth components were an individual session with an occupational health physician involving motivational interviewing and 5 multidisciplinary group sessions. The game was played by teams in 5 time periods, aiming to gain points by being physically active, as measured by an accelerometer. Data were collected in 2014 and 2015. Primary outcome was PA, defined as length of time at MET (metabolic equivalent task) ≥3, as measured by the accelerometer during the game. Secondary outcomes were reductions in BMI and waist circumference, measured at baseline and 10 and 23 weeks after the start of the program. Gaming elements such as “compliance” with the game (ie, days of accelerometer wear), “engagement” with the game (ie, frequency of reaching a personal monthly target), and “eHealth teams” (ie, social influence of eHealth teams) were measured as potential determinants of the outcomes. Linear mixed models were used to evaluate the effects on all outcome measures.

Results

The mean age of participants was 48.1 years; most participants were female (42/51, 82%). The mean PA was 86 minutes per day, ranging from 6.5 to 223 minutes, which was on average 26.2 minutes per day more than self-reported PA at baseline and remained fairly constant during the game. Mean BMI was reduced by 1.87 kg/m² (5.6%) and waist circumference by 5.6 cm (4.8%). The univariable model showed that compliance, engagement, and eHealth team were significantly associated with more PA, which remained significant for eHealth team in the multivariable model.

Conclusions

This blended Web-based gaming intervention was beneficial for overweight workers in becoming physically active above the recommended activity levels during the entire intervention period, and a favorable influence on BMI and waist circumference was observed. Promising components in the intervention, and thus targets for upscaling, are eHealth teams and engagement with the game. Broader implementation and long-term follow-up can provide insights into the sustainable effects on PA and weight loss and into who benefits the most from this approach.

Factor structure and internal reliability of an exercise health belief model scale in a Mexican population

Background

Mexico is one of the countries with the highest rates of overweight and obesity around the world, with 68.8% of men and 73% of women reporting both. This is a public health problem since there are several health related consequences of not exercising, like having cardiovascular diseases or some types of cancers. All of these problems can be prevented by promoting exercise, so it is important to evaluate models of health behaviors to achieve this goal. Among several models the Health Belief Model is one of the most studied models to promote health related behaviors. This study validates the first exercise scale based on the Health Belief Model (HBM) in Mexicans with the objective of studying and analyzing this model in Mexico.

Methods

Items for the scale called the Exercise Health Belief Model Scale (EHBMS) were developed by a health research team, then the items were applied to a sample of 746 participants, male and female, from five cities in Mexico. The factor structure of the items was analyzed with an exploratory factor analysis and the internal reliability with Cronbach’s alpha.

Results

The exploratory factor analysis reported the expected factor structure based in the HBM. The KMO index (0.92) and the Barlett’s sphericity test (p < 0.01) indicated an adequate and normally distributed sample. Items had adequate factor loadings, ranging from 0.31 to 0.92, and the internal consistencies of the factors were also acceptable, with alpha values ranging from 0.67 to 0.91.

Conclusions

The EHBMS is a validated scale that can be used to measure exercise based on the HBM in Mexican populations.