Relationships between measures of fitness, physical activity, body composition and vascular function in children

The Effects of a School-Based Physical Activity Program on Physical Fitness in Egyptian Children: A Pilot Study from the DELICIOUS Project

BACKGROUND

Ensuring the physical fitness of Egyptian children is of paramount importance to their overall well-being, given the unique socio-cultural and educational barriers they face that may hinder their active participation. As part of the DELICIOUS project, the "Be Fit Program" aims to increase the level of physical fitness among Egyptian school-aged children. This study explores the effectiveness of a structured, six-week physical activity (PA) program in improving various facets of physical fitness in children, including body composition, speed, coordination, muscular strength, and cardiovascular endurance. With the increasing prevalence of sedentary lifestyles, such efforts are imperative to improve overall health outcomes.

METHODS

A cohort of 125 children, aged 8.50 to 12.25 y (mean age 10.19 ± 1.03 y), participated in the study. Their body composition, speed, coordination, strength, and aerobic fitness were assessed before and after the Be Fit Program using the revised International Physical Performance Test Profile. Paired t-tests were used to detect changes between the pre- and post-tests.

RESULTS

Following the six-week intervention, statistical analyses revealed significant improvements in coordination and lower body strength (p < 0.01). Aerobic endurance showed marginal improvements, approaching statistical significance (p = 0.06). Conversely, there were no statistically significant changes in body composition, speed, or upper body strength (p > 0.05).

CONCLUSIONS

The study confirms that tailored, non-competitive physical activities can positively influence specific fitness components in Egyptian children. However, achieving holistic improvements across all targeted fitness domains may require further strategic adjustments or a longer program duration. This pilot study underscores the importance of culturally tailored, school-based PA programs and highlights the continued need for research and program refinement to comprehensively improve children's fitness in the Egyptian context.

Muscle Mass as a Biomarker for Health Status and Function in Pediatric Individuals with Neuromuscular Disabilities: A Systematic Review

This systematic review aims to investigate the relationship between muscle mass and specific health outcomes in pediatric populations with neuromuscular disorders. A search was performed for any relevant studies published in English from 1996 to 2023 in five databases. To be included in this analysis, articles must have had participants with an average age ≤21, focus on children with neuromuscular disabilities, and primarily examine relationships between muscle mass and any functional or health outcomes measure. Studies including typically developing children were used to contrast and enhance findings. Thirty-two studies were included, with 10,129 unique individuals represented: seventeen studies focused on healthy/typically developing children; seven on children with cerebral palsy; three on children with Duchenne muscular dystrophy; two on children with sarcopenia; and one study each on children with osteoporosis, congenital muscular dystrophy, and other various neurologic disorders. Thirteen studies assessed functional outcomes, ten assessed bone outcomes, and nine assessed other cardiovascular/metabolic outcomes. All of the included studies demonstrated relationships between muscle mass and respective outcomes in varying measures. The results of this review demonstrate that there is a consistently recognized relationship between muscle mass and important health outcomes in children, supporting clinically targeting muscle mass as a means to optimize desired outcomes.

Effects of different types of exercise intensity on improving health-related physical fitness in children and adolescents: a systematic review

A substantial body of empirical evidence reveals that physical activity is associated with a wide range of positive physical and mental health outcomes. However, an absence of comprehensive syntheses is observed concerning the varying effects of different exercise intensities on the improvement of physical health among children and adolescents. The aim of this review is to systematically investigate the effects of different exercise intensities on the physical fitness of children and adolescents, to analyses the optimal exercise intensities for improving physical fitness, and to provide a relevant theoretical basis for optimizing school physical education curricula. A systematic search strategy was used in this study in four online databases (PubMed, Scopus, EBSCO and Web of Science). Intervention studies that met the inclusion criteria underwent a thorough screening process, and their methodological quality was assessed utilizing the PEDro scale. The selected literature was systematically analyzed and evaluated through induction, summary, analysis, and evaluation. These findings indicate that high-intensity exercise training exerts significant positive effects on body composition, cardiopulmonary function and muscle fitness in children and adolescents. Therefore, we suggest that schools should focus on high-intensity sports in their physical education curriculum, which can further improve the student's PHYSICAL FITNESS.

Association between arterial health and cognition in adolescents: The PANIC study

We investigated the associations of the measures of arterial health with cognition in adolescents and whether physical activity (PA) or sedentary time (ST) confounds these associations. One hundred sixteen adolescents (71 boys) aged 15.9 ± 0.4 participated in the study. PA and ST were assessed using a combined accelerometer/heart rate monitor. Overall cognition was computed from the results of psychomotor function, attention, working memory, and paired-associate learning tests. Pulse wave velocity was measured by impedance cardiography, carotid intima-media thickness, and carotid artery distensibility by carotid ultrasonography. Systolic and diastolic blood pressure (SBP and DBP) were measured using an aneroid sphygmomanometer. SBP was inversely associated with overall cognition (standardized regression coefficient [β] = -0.216, 95% confidence interval (CI) -0.406 to -0.027, p = 0.025). Pulse wave velocity (β = -0.199, 95% CI -0.382 to -0.017, p = 0.033) was inversely associated with working memory task accuracy. SBP was directly associated with reaction time in the attention (β = 0.256, 95% CI 0.069 to 0.443, p = 0.008) and errors in the paired-associate learning tasks (β = 0.308, 95% CI 0.126 to 0.489, p = 0.001). Blood pressure was inversely associated with overall cognition. PA or ST did not confound the associations. Results suggest that preventing high blood pressure is important for promoting cognition in adolescents.

A 5-Week Guided Active Play Program Modulates Skin Microvascular Reactivity in Healthy Children

PURPOSE

Children's poor levels of physical activity (PA) participation and early-onset vascular aging are identified as global health challenges. Children's guided activity play (GAP)-based PA programs have emerged as effective strategies to improve cardiovascular risk factors and health-related fitness. This study proposes to investigate whether GAP improves children's cutaneous microvascular reactivity and health-related fitness.

METHODS

Children's (n = 18; 9.8 [1.5] y) PA during a 5-week (4 d/wk; 1 h/d) GAP program was assessed (accelerometry) with preassessments and postassessments for anthropometric, musculoskeletal fitness, blood pressure, estimated aerobic power, and cutaneous microvascular reactivity.

RESULTS

PA averaged 556 (132) kcal·week-1 at 34.7% (7.5%) time at moderate to vigorous intensity. Resting heart rate (-9.5%) and diastolic blood pressure (-7.8%) were reduced without changes in health-related fitness indices. Cutaneous microvascular reactivity to sodium nitroprusside iontophoresis increased the average perfusion (+36.8%), average cutaneous vascular conductance (+30%), the area under the curve (+28.8%), and a faster rise phase (+40%) of perfusion (quadratic modeling; P ≤ .05). Chi-square and crosstabulation analysis revealed significant association between children's PA levels and sodium nitroprusside average perfusion levels, where children with PA levels ≥205.1 kcal.55 minute-1 were overrepresented in the medium/high levels of sodium nitroprusside perfusion.

CONCLUSION

A 5-week GAP modified the microvascular reactivity in children without changes in body mass, musculoskeletal fitness, or estimated aerobic power.

The effect of 4 weeks of high-intensity interval training and 2 weeks of detraining on cardiovascular disease risk factors in male adolescents

NEW FINDINGS

What is the central question of this study? What is the effect of 4 weeks of high-intensity interval training (HIIT) and 2 weeks of detraining on vascular function and traditional cardiovascular disease (CVD) risk factors in male adolescents? What is the main finding and its importance? Four weeks of HIIT improved macrovascular function in adolescents. However, this training period did not measurably change microvascular function, body composition or blood biomarkers. Following 2 weeks of detraining, the improvement in flow-mediated dilatation (FMD) was lost. This highlights the importance of the continuation of regular exercise for the primary prevention of CVD.

ABSTRACT

High-intensity interval training (HIIT) represents an effective method to improve cardiometabolic health in adolescents. This study aimed to investigate the effect of 4 weeks of HIIT followed by 2 weeks of detraining on vascular function and traditional cardiovascular disease (CVD) risk factors in adolescent boys. Nineteen male adolescents (13.3 ± 0.5 years) were randomly allocated to either a training (TRAIN, n = 10) or control (CON, n = 9) group. Participants in TRAIN completed 4 weeks of HIIT running with three sessions per week. Macro- (flow-mediated dilatation, FMD) and microvascular (peak reactive hyperaemia, PRH) function, body composition (fat mass, fat free mass, body fat percentage) and blood biomarkers (glucose, insulin, total cholesterol, high- and low-density lipoprotein, triacylglycerol) were assessed pre-, 48 h post- and 2 weeks post-training for TRAIN and at equivalent time points for CON. Following training, FMD was significantly greater in TRAIN compared to CON (9.88 ± 2.40% and 8.64 ± 2.70%, respectively; P = 0.036) but this difference was lost 2 weeks after training cessation (8.22 ± 2.47% and 8.61 ± 1.99%, respectively; P = 0.062). No differences were detected between groups for PRH (P = 0.821), body composition (all P > 0.14) or blood biomarkers (all P > 0.18). In conclusion, 4 weeks of HIIT improved macrovascular function; however, this training period did not measurably change microvascular function, body composition or blood biomarkers. The reversal of the FMD improvement 2 weeks post-training highlights the importance of the continuation of regular exercise for the primary prevention of CVD.

The Use of Wearable Technologies in the Assessment of Physical Activity in Preschool- and School-Age Youth: Systematic Review

In recent years, physical activity assessment has increasingly relied on wearable monitors to provide measures for surveillance, intervention, and epidemiological research. This present systematic review aimed to examine the current research about the utilization of wearable technology in the evaluation in physical activities of preschool- and school-age children. A database search (Web of Science, PubMed and Scopus) for original research articles was performed. A total of twenty-one articles met the inclusion criteria, and the Cochrane risk of bias tool was used. Wearable technology can actually be a very important instrument/tool to detect the movements and monitor the physical activity of children and adolescents. The results revealed that there are a few studies on the influence of these technologies on physical activity in schools, and most of them are descriptive. In line with previous research, the wearable devices can be used as a motivational tool to improve PA behaviors and in the evaluation of PA interventions. However, the different reliability levels of the different devices used in the studies can compromise the analysis and understanding of the results.

Cardiorespiratory Fitness, Fat Mass, and Cardiometabolic Health with Endothelial Function, Arterial Elasticity, and Stiffness

PURPOSE

This study aimed to determine whether estimated cardiorespiratory fitness (CRF), fat mass (FM), lean mass (LM), and adiponectin bidirectionally associate with arterial function and structure and if CRF mediates the relationship between cardiometabolic health and arterial outcomes in 9- to 11-yr-old children drawn from the Avon Longitudinal Study of Parents and Children birth cohort, United Kingdom.

METHODS

Brachial artery flow-mediated dilation (FMD), distensibility coefficient (DC), and carotid-radial pulse wave velocity (PWV) were measured by ultrasonography; CRF was measured during the submaximal ergometer test; total FM, trunk FM, and LM were measured by dual-energy x-ray absorptiometry; plasma adiponectin was measured by enzyme assay; and cardiometabolic health was computed based on the International Diabetes Federation criteria for diagnosing metabolic syndrome. We tested bidirectionality by including CRF, FM, LM, and adiponectin as exposures and FMD, DC, and PWV as outcomes, alternatively.

RESULTS

Among 5566 participants (2816 (51%) girls; median age, 9.75 yr), CRF per body mass0.21 was directly related to DC (β (95% confidence interval) = 0.004 (<0.0001 to 0.008); P = 0.046), whereas CRF per LM0.54 was inversely associated with PWV (-0.034 (-0.063 to -0.003); 0.032) after adjusting for covariates. These associations remained in bidirectional analyses. Total FM, trunk FM, and LM were bidirectionally and positively associated with FMD and DC. Total FM and trunk FM but not LM had bidirectional and inverse associations with PWV. Adiponectin was not related to FMD, DC, or PWV. CRF partially mediated the associations of cardiometabolic health with FMD (1.5% mediation), DC (12.1% mediation), and PWV (3.5% mediation).

CONCLUSIONS

Associations of poor cardiometabolic health with adverse arterial structure and function in childhood may be mitigated by increasing CRF. Higher CRF was associated with better arterial structure whereas higher total FM and trunk FM were associated with better arterial function and structure. In the reverse analysis, healthy arterial structure and function were independently associated with increased total FM and trunk FM, suggesting an "arterial paradox."

Vascular Ageing in Youth: A Call to Action

Extensive evidence shows that risk factors for cardiovascular disease (CVD) begin to develop early in life. Childhood obesity and elevated blood pressure (BP) have become overwhelmingly challenging, with 57% of today's children predicted to be obese by the age of 35 years, and global rates of hypertension in children and adolescents increasing by 75% from 2000 to 2015. Thus, there is an urgent need for tools that can assess early CVD risk in youth, which may lead to better risk stratification, preventative intervention, and personalised medicine. Vascular ageing (the deterioration in vascular structure and function) is a pivotal progenitor of health degeneration associated with elevated BP. Exposure to adverse environmental and genetic factors from fetal life promotes the development and accumulation of subclinical vascular changes that direct an individual towards a trajectory of early vascular ageing (EVA)-an independent predictor of target organ damage in the heart, brain, and kidneys. Therefore, characterising vascular ageing from youth may provide a window into cardiovascular risk later in life. However, vascular ageing measurements only have value when techniques are accurate/validated and when reliable thresholds are available for defining normal ranges and ranges that signal increased risk of disease. The aim of this paper is to summarise current evidence on the importance of vascular ageing assessment in youth and the impact of interventions to prevent or delay EVA, to highlight the need for standardisation and validation of measurement techniques in children and adolescents, and the importance of establishing reference values for vascular ageing measures in this population.

Longitudinal associations of physical activity, sedentary time, and cardiorespiratory fitness with arterial health in children - the PANIC study

We investigated the longitudinal associations of physical activity (PA), sedentary time (ST), and cardiorespiratory fitness (CRF) with arterial health among children. In our primary analyses, we investigated 245 children (girls 51.8%) aged 6-9 years participating in the baseline examinations who had data on arterial health at 2-year follow-up. We also utilized a subsample of 90 children who had a complete arterial health data at baseline and 2-year follow-up. ST (≤1.5 METs), light PA (>1.5-4 METs), moderate PA (>4-7 METs), vigorous PA (>7METs), and moderate-to-vigorous PA (MVPA, >4 METs) were assessed by combined movement and heart rate monitoring and CRF by maximal exercise testing on a cycle ergometer at baseline and 2-year follow-up. Stiffness index (SI) as a measure of arterial stiffness and change in reflection index during exercise test (DRI) as a measure of arterial dilation capacity were assessed by pulse contour analysis. Two-year change in vigorous PA was associated with DRI in boys but not in girls (p=0.021 for interaction). In a subsample analyses, 2-year changes in MPA, VPA, and MVPA were inversely associated with 2-year change in SI. In conclusion, promoting PA at higher intensities may confer larger benefits on arterial health than reducing ST and increasing LPA.

Sedentary Behavior in Childhood, Lower Arterial Compliance and Decreased Endothelial Function-Cross Sectional Data From a German School Cohort

BACKGROUND

Endothelial function by flow-mediated dilatation assesses early markers of atherosclerotic progression. Greater amounts of physical activity and physical fitness in children are associated with cardiovascular health benefits. We aimed to explore factors, influencing endothelial function and arterial compliance in a cohort of healthy school children.

METHODS

The 94 participants (41 girls, 53 boys) in the study were young, healthy children from a German school cohort. Anthropometric data, body composition and blood pressure were assessed. Blood was drawn (8 h overnight fast), assessing total cholesterol, high density lipoprotein and low density lipoprotein and triglycerides. Endothelial function was diagnosed by flow-mediated dilatation with ultrasonography (ALOKA/Hitachi, Prosound alpha 6). Tracking gates were set on the intima in B-mode. The waveform of diameter changes over the cardiac cycle was displayed in real time using the FMD-mode of the eTRACKING system. Changes in arterial diameter at baseline, ischaemia and vasodilatation were measured. A symptom limited pulmonary exercise test on a bicycle ergometer was performed to test cardiorespiratory fitness. Physical activity was assessed using GT3x accelerometers (Actigraph, USA), over 4 days (including 1 week-end day), with a minimum wear-time duration of 10 h.

RESULTS

The median age was 12.2 years (11.8-12.8). Children were normal weight, blood lipid profiles (cholesterol, high-density lipoprotein, low-density lipoprotein, triglyceride) were in normal range. Baseline measurements during the diagnostics of endothelial function revealed higher arterial compliance of the brachial artery in boys. Boys' cardiorespiratory fitness was higher than compared to girls. Boys met the recommendations of 60 min moderate to vigorous activity, whereas girls were significantly less active and did not meet current recommendations. More time spent in sedentary activity was the main predictor for lower arterial compliance (adjusted for age and sex), accounting for 14% of the variance. No significant model revealed, analyzing the influencing factors such as anthropometric data, blood lipids, physical activity and fitness on endothelial function.

CONCLUSION

This is the first study on endothelial function in association to objectively measured physical activity and cardiorespiratory fitness in healthy school children in Germany. The study highlights the importance of reducing time spent being sedentary to maintain endothelial health.

The acute effect of high- and moderate-intensity interval exercise on vascular function before and after a glucose challenge in adolescents

NEW FINDINGS

What is the central question of this study? What is the effect of high-intensity and moderate-intensity interval running on macro- and microvascular function in a fasted state and following a glucose challenge in adolescents? What is the main finding and its importance? Both macro- and microvascular function were improved after interval running independent of intensity. This finding shows that the intermittent exercise pattern and its associated effect on shear are important for vascular benefits. In adolescents, macrovascular function was enhanced after an acute glucose load. However, the effect of chronic glucose consumption on vascular function remains to be elucidated.

ABSTRACT

Interventions targeting vascular function in youth are an important strategy for the primary prevention of cardiovascular diseases. This study examined, in adolescents, the effect of high-intensity interval running (HIIR) and moderate-intensity interval running (MIIR) on vascular function in a fasted state and postprandially after a glucose challenge. Fifteen adolescents (13 male, 13.9 ± 0.6 years) completed the following conditions on separate days in a counterbalanced order: (1) 8 × 1 min HIIR interspersed with 75 s recovery; (2) distance-matched amount of 1 min MIIR interspersed with 75 s recovery; and (3) rest (CON). Macro- (flow-mediated dilatation, FMD) and microvascular (peak reactive hyperaemia, PRH) function were assessed immediately before and 90 min after exercise/rest. Participants underwent an oral glucose tolerance test (OGTT) 2 h after exercise/rest before another assessment of vascular function 90 min after the OGTT. Following exercise, both HIIR and MIIR increased FMD (P = 0.02 and P = 0.03, respectively) and PRH (P = 0.04, and P = 0.01, respectively) with no change in CON (FMD: P = 0.51; PRH: P = 0.16) and no significant differences between exercise conditions. Following the OGTT, FMD increased in CON (P < 0.01) with no changes in HIIR and MIIR (both P > 0.59). There was no change in PRH after the OGTT (all P > 0.40). In conclusion, vascular function is improved after interval running independent of intensity in adolescents. Acute hyperglycaemia increased FMD, but prior exercise did not change vascular function after the OGTT in youth.

Association Between Physical Activity Intensity Levels and Arterial Stiffness in Healthy Children

BACKGROUND

Physical activity (PA) has a substantial impact on arterial stiffness in adults; however, evidence regarding children is scarce. The aim of this study was to examine the association between objectively measured PA with different intensities and surrogate measures of arterial stiffness in healthy children.

METHODS

Altogether, 80 children (41 girls and 39 boys, ranging from 8-11 y) participated in this prospective, cross-sectional study. Sedentary time and PA of light, moderate, and vigorous intensity levels were measured over a period of 7 days by accelerometry. Arterial stiffness parameters, including pulse wave velocity and central systolic blood pressure (cSBP), were noninvasively assessed by the oscillometric Mobil-O-Graph. Associations were tested using multiple linear regressions with adjustments for potential confounders (α ≤ .05).

RESULTS

PA of moderate intensity was negatively associated with cSBP (β = -0.266, P = .017). PA of vigorous intensity was inversely related to pulse wave velocity (β = -0.225, P = .045) and cSBP (β = -0.286, P = .010), respectively.

CONCLUSION

Higher time spent in PA of moderate and vigorous intensity is associated with reduced pulse wave velocity and lower cSBP values in children. It suggests that PA is a favorable determinant of arterial health.

Are school-based physical activity interventions effective and equitable? A meta-analysis of cluster randomized controlled trials with accelerometer-assessed activity

The prevalence of childhood obesity is increasing at epidemic rates globally, with widening inequalities between advantaged and disadvantaged groups. Despite the promise of schools as a universal context to access and influence all children, the potential of school-based interventions to positively impact children's physical activity behaviour, and obesity risk, remains uncertain. We searched six electronic databases to February 2017 for cluster randomized trials of school-based physical activity interventions. Following data extraction, authors were sent re-analysis requests. For each trial, a mean change score from baseline to follow-up was calculated for daily minutes of accelerometer-assessed moderate-to-vigorous physical activity (MVPA), for the main effect, by gender, and by socio-economic position (SEP). Twenty-five trials met the inclusion criteria; 17 trials provided relevant data for inclusion in the meta-analyses. The pooled main effect for daily minutes of MVPA was nonexistent and nonsignificant. There was no evidence of differential effectiveness by gender or SEP. This review provides the strongest evidence to date that current school-based efforts do not positively impact young people's physical activity across the full day, with no difference in effect across gender and SEP. Further assessment and maximization of implementation fidelity is required before it can be concluded that these interventions have no contribution to make.

Physical Activity, BMI, and Blood Pressure in US Youth: NHANES 2003-2006

PURPOSE

The objective of this study was to examine the independent and combined association of physical activity and body mass index (BMI) with blood pressure in youth.

METHODS

Youth aged 8-18 years from the 2003-2006 National Health and Nutrition Examination Survey (NHANES) with BMI, blood pressure, and physical activity (accelerometer) were included in the analyses. A total of 2585 subjects (1303 males; 47% of all 8- to 18-year-olds) met these criteria.

RESULTS

Obese youth had a systolic blood pressure that was 8 mm Hg higher than normal weight youth. A significant interaction between BMI and physical activity on blood pressure was found (P < .001), and group differences among the BMI/activity groups showed that the 3 obese groups and the overweight/least active group had significantly higher systolic blood pressure than the normal weight/active group across all analyses. The overweight/least active and normal weight/least active groups had significantly higher diastolic blood pressure than the normal weight/active group as well.

CONCLUSIONS

This study showed a significant independent and combined association of BMI and physical activity with blood pressure in youth. Interventions need to focus on the reduction of fatness/BMI as a way to reduce the cardiovascular risk in youth.

Cardiovascular adaptations after 10 months of intense school-based physical training for 8- to 10-year-old children

This study examined cardiovascular adaptations in 8- to 10-year-old schoolchildren after 10 months (a full school year) of 3 × 40 minute per week of small-sided ball games (SSG, including football, basketball, and/or floorball) or circuit strength training (CST). The study involved 291 Danish schoolchildren, 8-10 years old, cluster-randomized to SSG (n = 93, 4 schools, 5 classes), CST (n = 83, 4 schools, 4 classes), or a control group (CON, n = 115, 2 schools, 5 classes). Before and after the 10-month intervention, resting heart rate and blood pressure measurements were performed as well as comprehensive transthoracic echocardiography and peripheral arterial tonometry (PAT). Analysis of baseline-to-10-months changes showed between-group differences (P < 0.05) after both training interventions in diastolic blood pressure (delta scores: SSG -2.1 ± 6.0 mm Hg; CST -3.0 ± 7.1 mm Hg; CON 0.2 ± 5.3 mm Hg). Moreover, there were between-group differences in delta scores (P < 0.05) in interventricular septum thickness (SSG 0.17 ± 0.87 mm; CST 0.30 ± 0.94 mm; CON -0.15 ± 0.68 mm), left-atrial volume index (SSG 0.32 ± 5.13 mL/m² ; CON 2.60 ± 5.94 mL/m² ), and tricuspid annular plane systolic excursion (SSG -0.4 ± 3.3 mm; CON: 0.1 ± 3.6 mm). No significant between-group differences were observed for the PAT-derived reactive hyperemia index. In conclusion, 10 months of 3 × 40 minutes per week of SSG and CST in 8- to 10-year-old children decreased diastolic blood pressure and elicited discrete cardiac adaptations, suggesting that intense physical exercise in school classes can have effects on cardiovascular health in children.

ULTRASONOGRAPHIC MARKERS OF CARDIOVASCULAR DISEASE RISK IN OBESE CHILDREN

Objective:

To evaluate whether the obesity alters ultrasonographical markers of metabolic and cardiovascular disease risk in children.

Methods:

A cross-sectional study evaluated 80 children aged between 6 and 10 years, comparing 40 obese with 40 normal children. The following parameters were assessed: weight; height; body mass index; arterial blood pressure; body fat; basal metabolic rate; HDL-cholesterol, LDL-cholesterol and total cholesterol; fasting insulin and glucose; quantitative insulin sensitivity check index (QUICKI); homeostasis model of assessment - insulin resistance (HOMA-IR); basal diameter of the brachial artery; brachial artery flow mediated dilation (FMD) and of pulsatility index change (PI-C).

Results:

Significant differences were observed between obese vs. non-obese children: systolic blood pressure (97.7±8.4 vs. 89.0±5.8 mmHg; p<0.01), diastolic blood pressure (64.3±7.9 vs. 52.9±5.1 mmHg; p<0.01), proportion of body fat (45.1±5.9 vs. 21.3±6.0%; p<0.01), basal metabolic rate (1216.1±102.1 vs. 1072.9±66.4 Kcal; p<0.01), total cholesterol (164.7±25.2 vs. 153.4±15.8 mg/dL; p=0.03), fasting insulin (7.1±5.2 vs. 2.8±1.8 pIU/mL; p<0.01), HOMA-IR (1.5±1.1 vs. 0.6±0.4; p<0.01), basal diameter of the brachial artery (2.5±0.3 vs. 2.1±0.3 mm; p<0.01); PI-C (-15.5±27.2 vs. -31.9±15.5%; p<0.01), decreased QUICKI (0.4±0.05 vs. 0.4±0.03; p<0.01), and FMD (6.6±3.2 vs. 15.6±7.3%; p<0.01).

Conclusions:

Obesity worsens ultrasonographical and laboratorial markers of metabolic and cardiovascular disease risk in children.

The CHANGE! Project: Changes in Body Composition and Cardiorespiratory Fitness in 10- to 11-Year-Old Children After Completing the CHANGE! Intervention

PURPOSE

To assess the effects of the Children's Health, Activity and Nutrition: Get Educated! intervention on body size, body composition, and peak oxygen uptake in a subsample of 10- to 11-year-old children.

METHODS

Sixty children were recruited from 12 schools (N = 6 intervention) to take part in the CHANGE! subsample study. Baseline, postintervention, and follow-up measures were completed in October 2010, March-April 2011, and June-July 2011, respectively. Outcome measures were body mass index z score, waist circumference, body composition assessed using dual-energy X-ray absorptiometry (baseline and follow-up only), and peak oxygen uptake.

RESULTS

Significant differences in mean trunk fat mass (control = 4.72 kg, intervention = 3.11 kg, P = .041) and trunk fat % (control = 23.08%, intervention = 17.75%, P = .022) between groups were observed at follow-up. Significant differences in waist circumference change scores from baseline to follow-up were observed between groups (control = 1.3 cm, intervention = -0.2 cm, P = .023). Favorable changes in body composition were observed in the intervention group; however, none of these changes reached statistical significance. No significant differences in peak oxygen uptake were observed.

CONCLUSIONS

The results of the present study suggest the multicomponent curriculum intervention had small to medium beneficial effects on body size and composition health outcomes.

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.

Associations of Objectively Measured Physical Activity and Sedentary Time With Arterial Stiffness in Pre-Pubertal Children

PURPOSE

To investigate the relationships of objectively measured physical activity (PA) and sedentary time (ST) to arterial stiffness in prepubertal children.

METHOD

Altogether 136 children (57 boys, 79 girls) aged 6-8-years participated in the study. Stiffness index (SI) was assessed by pulse contour analysis based on photoplethysmography. ST, light PA, moderate PA, and vigorous PA were assessed using combined acceleration and heart rate monitoring. We investigated the associations of ST (<1.5METs) and time spent in intensity level of PA above 2-7METs in min/d with SI using linear regression analysis. We studied the optimal duration and intensity of PA to identify children being in the highest quarter of SI using Receiver Operating Characteristics curves.

RESULTS

Moderate PA, vigorous PA, and cumulative time spent in PA above 3 (β=-0.279, p = .002), 4 (β =-0.341, P<0.001), 5 (β =-0.349, P<0.001), 6 (β =-0.312, P<0.001), and 7 (β =-0.254, p = .005) METs were inversely associated with SI after adjustment for age, sex, and monitor wear time. The cutoffs for identifying children being in the highest quarter of SI <68 min/d for PA exceeding 5 METs and <26 min/d for PA exceeding 6 METs.

CONCLUSION

Lower levels of PA exceeding 3-6 METs were related to higher arterial stiffness in children.

The gender gap among school children in poor rural areas of western China: evidence from a multi-province dataset

Background

The gender gap remains a major impediment in the path towards equality and it is especially wide in low-income countries. Up to the early 2000s, many studies documented extensive inequalities in China: girls had poorer health, less nutrition and less education than their male counterparts. The goal of this study is to examine whether the gender gap persists, given that China is now making the transition into the ranks of upper-middle income countries. We consider educational outcomes, mental and physical health status, as well as non-cognitive outcomes.

Methods

We draw on a dataset containing 69,565 observations constructed by combining data from 7 different school-level surveys spanning 5 provinces. The surveys were all conducted by the authors between 2008 and 2013 using uniform survey instruments and data collection protocols in randomly selected schools across western provinces in rural China. The sample children range in age from 9 to 14 years (with 79 % of the sample being aged 10 to 12). Our analysis compares rural girls with rural boys in terms of 13 different indicators.

Results

With the exception of anemia rates, the health outcomes of girls are equal to those of boys. Girls and boys are statistically identical in terms of weight-for-age, height-for-age, and prevalence of intestinal worm infections. Girls performed better than boys on five of six cognitive and educational performance indicators. Girls performed worse than boys on all mental health indicators. All estimates are robust to the inclusion of different age ranges, controlling for the level of household assets, ethnic minority status, as well as the addition of provincial dummies.

Conclusions

Our findings suggest that with the exception of non-cognitive outcomes, anemia and standardized math test scores, the gender gap in our study areas in China appears to be diminishing.

The Case for Vigorous Physical Activity in Youth

Although it is widely recognized that regular physical activity is associated with a variety of health-related benefits in youths, the extent to which vigorous physical activity, as opposed to moderate or light physical activity, may be especially beneficial for youths is not completely understood. This review will examine the evidence for the efficacy of vigorous physical activity for promoting the well-being of youths as indicated by body composition, physical fitness, cardiometabolic biomarkers, and cognitive function. Potential caveats associated with the promotion of vigorous physical activity among youths will also be discussed, as will the inclusion of vigorous physical activity in current recommendations by national organizations for physical activity among youths.

Aerobic Function and Muscle Deoxygenation Dynamics during Ramp Exercise in Children

PURPOSE

This study aimed to characterize changes in deoxyhemoglobin ([HHb]) response dynamics in boys and girls during ramp incremental exercise to investigate whether the reduced peak oxygen uptake (peak V˙O2) in girls is associated with poorer matching of muscle O2 delivery to muscle O2 utilization, as evidenced by a more rapid increase in [HHb].

METHODS

Fifty-two children (31 boys, 9.9 ± 0.6 yr, 1.38 ± 0.07 m, 31.70 ± 5.78 kg) completed ramp incremental exercise on a cycle ergometer during which pulmonary gas exchange and muscle oxygenation parameters were measured.

RESULTS

When muscle [HHb] was expressed against absolute work rate and V˙O2, girls had an earlier change in [HHb], as evidenced by the lower c/d parameter (girls, 54 ± 20 W, vs boys, 67 ± 19 W, P = 0.023; girls, 0.82 ± 0.28 L·min(-1), vs boys, 0.95 ± 0.19 L·min(-1), P = 0.055) and plateau (girls, 85 ± 12 W, vs boys, 99 ± 18 W, P = 0.031; girls, 1.02 ± 0.25 L·min(-1), vs boys, 1.22 ± 0.28 L·min(-1), P = 0.014). However, when expressed against relative work rate or V˙O2, there were no sex differences in ([HHb]) response dynamics (all P > 0.20). Significant correlations were observed between absolute and fat-free mass normalized peak V˙O2 and the HHb c/d and plateau parameters when expressed against absolute work rate or V˙O2. Furthermore, when entered into a multiple regression model, the [HHb] plateau against absolute V˙O2 contributed 12% of the variance in peak V˙O2 after adjusting for fat-free mass, gas exchange threshold, and body fatness (model R2 = 0.81, P < 0.001).

CONCLUSIONS

The sex difference in peak V˙O2 in 9- to 10-yr-old children is, in part, related to sex-specific changes in muscle O2 extraction dynamics during incremental exercise.

Physical activity guidelines and cardiovascular risk in children: a cross sectional analysis to determine whether 60 minutes is enough

BACKGROUND

Physical activity reduces cardiovascular mortality and morbidity. The World Health Organisation (WHO) recommends children engage in 60 min daily moderate-to-vigorous physical activity (MVPA). The effect of compliance with this recommendation on childhood cardiovascular risk has not been empirically tested. To evaluate whether achieving recommendations results in reduced composite-cardiovascular risk score (CCVR) in children, and to examine if vigorous PA (VPA) has independent risk-reduction effects.

METHODS

PA was measured using accelerometry in 182 children (9-11 years). Subjects were grouped according to achievement of 60 min daily MVPA (active) or not (inactive). CCVR was calculated (sum of z-scores: DXA body fat %, blood pressure, VO2peak, flow mediated dilation, left ventricular diastolic function; CVR score ≥ 1SD indicated 'higher risk'). The cohort was further split into quintiles for VPA and odds ratios (OR) calculated for each quintile.

RESULTS

Active children (92 (53 boys)) undertook more MVPA (38 ± 11 min, P < 0.001), had greater VO2peak (4.5 ± 0.8 ml/kg/min P < 0.001), and lower fat % (3.9 ± 1.1 %, P < 0.001) than inactive. No difference were observed between active and inactive for CCVR or OR (P > 0.05). CCVR in the lowest VPA quintile was significantly greater than the highest quintile (3.9 ± 0.6, P < 0.05), and the OR was 4.7 times higher.

CONCLUSION

Achievement of current guidelines has positive effects on body composition and cardiorespiratory fitness, but not CCVR. Vigorous physical activity appears to have beneficial effects on CVD risk, independent of moderate PA, implying a more prescriptive approach may be needed for future VPA guidelines.

The Impact of Acculturation Level on Weight Status and Weight Outcomes in Hispanic Children

BACKGROUND

Previous studies revealed that higher levels of acculturation are related to obesity in Hispanic adults. Conflicting findings exist regarding this relationship in children, and little is known about the impact of acculturation on children's success in pediatric weight management programs. The purposes of the study were to (1) examine the relationship between acculturation and overweight/obese weight status and (2) determine the impact of acculturation on the changes in weight status among overweight/obese children 12 and 24 months after having participated in a weight management intervention.

METHODS

This is a secondary analysis of aggregated data from three randomized control trials that occurred between 2005 and 2009. Height, weight, and level of acculturation using the Child Short Scale for Hispanics (C-SASH) were measured in a sample of Hispanic children (n = 559). Logistic regression models were used to study phase 1 (n = 559) and phase 2 (n = 142), controlling for child and family characteristics.

RESULTS

Children reporting high levels of acculturation had a 52 % lower odds of being overweight or obese. Among overweight/obese children who participated in the intervention, high levels of acculturation demonstrated greater reductions in standardized body mass index (zBMI) at 24 months.

CONCLUSIONS

The results of this study indicate a need to tailor weight management programs for Hispanic children who have lower levels of acculturation.

Two weeks of high-intensity interval training improves novel but not traditional cardiovascular disease risk factors in adolescents

High-intensity interval training (HIIT) improves traditional cardiovascular disease (CVD) risk factors in adolescents, but no study has identified the influence of HIIT on endothelial and autonomic function in this group. Thirteen 13- to 14-yr-old adolescents (6 girls) completed six HIIT sessions over 2 wk. Each training session consisted of eight to ten 1-min repetitions of cycling at 90% peak power interspersed with 75 s of unloaded cycling. Traditional (triglycerides, cholesterol, glucose, insulin, and blood pressure) and novel [flow-mediated dilation (FMD), heart rate variability (HRV)] CVD risk factors were assessed in a fasted and postprandial state before (PRE), 1 day after (POST-1D), and 3 days after (POST-3D) training. Aerobic fitness was determined PRE and POST-3D. Two weeks of HIIT had no effect on aerobic fitness or traditional CVD risk factors determined in the fasted or postprandial state ( P > 0.15). Compared with PRE, fasted FMD was improved POST-1D [ P = 0.003, effect size (ES) = 0.70] but not POST-3D ( P = 0.32, ES = 0.22). Fasted FMD was greater POST-1D compared with POST-3D ( P = 0.04, ES = 0.48). Compared with PRE, postprandial FMD was greater POST-1D ( P < 0.001, ES = 1.01) and POST-3D ( P = 0.01, ES = 0.60). Fasted HRV was greater POST-1D ( P = 0.001, ES = 0.71) and POST-3D ( P = 0.02, ES = 0.44). The test meal lowered HRV in all laboratory visits ( P < 0.001, ES = 0.59), but there were no differences in postprandial HRV between visits ( P > 0.32 for all). Two weeks of HIIT enhanced endothelial function and HRV without improvements in traditional CVD risk factors. However, most of this favorable adaptation was lost POST-3D, suggesting that regularly performing high-intensity exercise is needed to maintain these benefits.

Accumulating exercise and postprandial health in adolescents

PURPOSE

To examine the influence of exercise intensity on postprandial health outcomes in adolescents when exercise is accumulated throughout the day.

METHODS

19 adolescents (9 male, 13.7±0.4 years old) completed three 1-day trials in a randomised order: (1) rest (CON); or four bouts of (2) 2×1 min cycling at 90% peak power with 75 s recovery (high-intensity interval exercise; HIIE); or (3) cycling at 90% of the gas exchange threshold (moderate-intensity exercise; MIE), which was work-matched to HIIE. Each bout was separated by 2 hours. Participants consumed a high fat milkshake for breakfast and lunch. Postprandial triacylglycerol (TAG), glucose, systolic blood pressure (SBP) and fat oxidation were assessed throughout the day.

RESULTS

There was no effect of trial on total area under the curve (TAUC) for TAG (P=0.87). TAUC-glucose was lower in HIIE compared to CON (P=0.03, ES=0.42) and MIE (P=0.04, ES=0.41), with no difference between MIE and CON (P=0.89, ES=0.04). Postprandial SBP was lower in HIIE compared to CON (P=0.04, ES=0.50) and MIE (P=0.04, ES=0.40), but not different between MIE and CON (P=0.52, ES=0.11). Resting fat oxidation was increased in HIIE compared to CON (P=0.01, ES=0.74) and MIE (P=0.05, ES=0.51), with no difference between MIE and CON (P=0.37, ES=0.24).

CONCLUSION

Neither exercise trial attenuated postprandial lipaemia. However, accumulating brief bouts of HIIE, but not MIE, reduced postprandial plasma glucose and SBP, and increased resting fat oxidation in adolescent boys and girls. The intensity of accumulated exercise may therefore have important implications for health outcomes in youth.

Impact of Health Status and Lifestyle Modifications on Vascular Structure and Function in Children and Adolescents

Until recently cardiovascular disease is often thought of as a disease that manifests itself during middle age. Researchers and clinicians have begun to realize that the initial signs of cardiovascular disease begin early on in childhood with changes present in both vascular structure and function. This increased recognition has resulted in considerable effort to develop accurate and reliable methods to measure as well as track changes in vascular structure and function applicable to study this process in children and adolescents. Certain genetic abnormalities and chronic diseases, which present or emerge in childhood often result in meaningful changes to vascular structure and function, which aid in our understanding of the vascular disease process. In this review, we will discuss different methods of assessing vascular structure and function, the diseases in childhood associated with decrements and maladaptive changes in the vascular system, and whether modification of lifestyle (ie, weight loss, dietary and/or exercise changes) can affect vascular structure and function in children.

Associations of cardiorespiratory fitness, physical activity, and adiposity with arterial stiffness in children

Associations of cardiorespiratory fitness (CRF), physical activity (PA), sedentary behavior, and body fat percentage (BF%) with arterial stiffness and dilation capacity were investigated in 160 prepubertal children (83 girls) 6-8 years of age. We assessed CRF (watts/lean mass) by maximal cycle ergometer exercise test, total PA, structured exercise, unstructured PA, commuting to and from school, recess PA and total and screen-based sedentary behavior by questionnaire, BF% using dual-energy X-ray absorptiometry, and arterial stiffness and dilation capacity using pulse contour analysis. Data were adjusted for sex and age. Poorer CRF (standardized regression coefficient β = -0.297, P < 0.001), lower unstructured PA (β = -0.162, P = 0.042), and higher BF% (β = 0.176, P = 0.044) were related to higher arterial stiffness. When CRF, unstructured PA, and BF% were in the same model, only CRF was associated with arterial stiffness (β = -0.246, P = 0.006). Poorer CRF was also related to lower arterial dilation capacity (β = 0.316, P < 0.001). Children with low CRF (< median) and high BF% (≥ median; P = 0.002), low CRF and low unstructured PA (< median; P = 0.006) or children with low unstructured PA and high BF% (P = 0.005) had higher arterial stiffness than children in the opposite halves of these variables. Poor CRF was independently associated with increased arterial stiffness and impaired arterial dilation capacity among children.

Exercise intensity and the protection from postprandial vascular dysfunction in adolescents

Acute exercise transiently improves endothelial function and protects the vasculature from the deleterious effects of a high-fat meal (HFM). We sought to identify whether this response is dependent on exercise intensity in adolescents. Twenty adolescents (10 male, 14.3 ± 0.3 yr) completed three 1-day trials: 1) rest (CON); 2) 8 × 1 min cycling at 90% peak power with 75 s recovery [high-intensity interval exercise (HIIE)]; and 3) cycling at 90% of the gas exchange threshold [moderate-intensity exercise (MIE)] 1 h before consuming a HFM (1.50 g/kg fat). Macrovascular and microvascular endothelial function was assessed before and immediately after exercise and 3 h after the HFM by flow-mediated dilation (FMD) and laser Doppler imaging [peak reactive hyperemia (PRH)]. FMD and PRH increased 1 h after HIIE [P < 0.001, effect size (ES) = 1.20 and P = 0.048, ES = 0.56] but were unchanged after MIE. FMD and PRH were attenuated 3 h after the HFM in CON (P < 0.001, ES = 1.78 and P = 0.02, ES = 0.59). FMD remained greater 3 h after the HFM in HIIE compared with MIE (P < 0.001, ES = 1.47) and CON (P < 0.001, ES = 2.54), and in MIE compared with CON (P < 0.001, ES = 1.40). Compared with CON, PRH was greater 3 h after the HFM in HIIE (P = 0.02, ES = 0.71) and MIE (P = 0.02, ES = 0.84), with no differences between HIIE and MIE (P = 0.72, ES = 0.16). Plasma triacylglycerol concentration and total antioxidant status concentration were not different between trials. We conclude that exercise intensity plays an important role in protecting the vasculature from the deleterious effects of a HFM. Performing HIIE may provide superior vascular benefits than MIE in adolescent groups.

Associations between bicycling and carotid arterial stiffness in adolescents: The European Youth Hearts Study

The aim of the study was to investigate the associations between bicycling and carotid arterial stiffness, independent of objectively measured moderate-and-vigorous physical activity. This cross-sectional study included 375 adolescents (age 15.7 ± 0.4 years) from the Danish site of the European Youth Heart Study. Total frequency of bicycle usage was assessed by self-report, and carotid arterial stiffness was assessed using B-mode ultrasound. After adjusting for pubertal status, body height, and objectively measured physical activity and other personal lifestyle and demographic factors, boys using their bicycle every day of the week displayed a higher carotid arterial compliance {standard beta 0.47 [95% confidence interval (CI) 0.07-0.87]} and distension [standard beta 0.38 (95% CI -0.04 to 0.81)]. Boys using their bicycle every day of the week furthermore displayed a lower Young's elastic modulus [standard beta -0.48 (95% CI -0.91 to -0.06)]. Similar trends were observed when investigating the association between commuter bicycling and carotid arterial stiffness. These associations were not observed in girls. Our observations suggest that increasing bicycling in adolescence may be beneficial to carotid arterial health among boys.

Scaling of peak oxygen uptake in children: a comparison of three body size index models

PURPOSE

We aimed to compare three candidate body size index models for the scaling of aerobic fitness (V(˙)O(2peak)) in children: whole body mass, total lean body mass, and the lean mass of both legs.

METHODS

V(˙)O(2peak) and total lean mass of the body and both legs (via dual-energy x-ray absorptiometry) were assessed in 126 girls and 87 boys aged 9-11 yr. We applied nonlinear allometric models of the form V(˙)O(2peak) = a×body size, adjusted for biological sex and maturity offset (years from peak height velocity). We assessed goodness of fit using the Akaike information criterion.

RESULTS

The Akaike weights (Akaike differences) were as follows: lean mass of both legs = 0.69 (0), total lean body mass = 0.31 (1.6), and whole body mass = <1e-8 (36.6). The size exponent (90% confidence interval) for the lean mass of both legs was 0.55 (0.46-0.64). V(˙)O(2peak) was 17% (13%-21%) lower in girls after controlling for the lean mass of both legs and maturity offset. After controlling for body size and sex, a 1-yr increase in maturity offset (closer to peak height velocity) was associated with a 6% (4%-9%) higher V(˙)O(2peak).

CONCLUSIONS

Allometric scaling of V(˙)O(2peak) by the lean mass of both legs provides the best model for quantifying growth-related changes in aerobic fitness in pediatric populations, although this model is only marginally superior to the total lean body mass model. There is no support for the total body mass model. Maturity and sex are also important covariates exerting a size-independent influence on peak aerobic fitness.

Assessment of biochemical liver markers, physical activity, fitness and body mass index for a cardiometabolic risk model in childhood

AIM

The aim of this study was to investigate clustered cardiometabolic risk scores in healthy 10- to 12-year-olds using anthropometric characteristics, measurements of cardiorespiratory fitness (CRF) and physical activity and blood markers of metabolic disease. We also evaluated how including markers of liver cell injury would affect the clustered cardiometabolic risk assessment model.

METHODS

This cross-sectional study focused on 99 children aged 10-12 years. The main outcome included assessing participants with increased and low cardiometabolic risk factors using a clustered risk score model that incorporated markers implicated in metabolic syndrome pathogenesis. Two clustered risk scores were calculated, one incorporating markers of liver cell injury.

RESULTS

Children classified as 'increased risk' exhibited significantly lower CRF and higher body mass index Z-scores than their 'low-risk' peers. No significant differences in physical activity were observed. This trend remained unchanged when markers of liver injury were included in the clustered risk assessment model.

CONCLUSION

The clustered risk score model is a scientifically robust method of cardiometabolic risk assessment, which reiterates the importance of weight reduction and CRF promotion in childhood. Our study did not show a significant contribution of liver injury markers, and further research is needed to evaluate their effect on cardiometabolic risk stratification in childhood.

Physical activity, cardiorespiratory fitness, and clustered cardiometabolic risk in 10- to 12-year-old school children: the REACH Y6 study

OBJECTIVES

(1) Investigate whether clustered cardiometabolic risk score, cardiorespiratory fitness (CRF), sedentary time (ST), and body mass index Z-scores (BMI Z-scores), differed between participants that met and did not achieve ≥60 min of daily moderate to vigorous intensity physical activity (MVPA). (2) Compare clustered cardiometabolic risk score, BMI Z-score, ST, and MVPA by CRF status.

METHODS

One hundred and one (n = 45 boys) 10- to 12-year-old participants took part in this cross-sectional study, conducted in Liverpool (Summer 2010) and Ulster (Spring 2011) UK. Assessments of blood markers, stature, sitting stature, body mass, waist circumference, flow mediated dilation (FMD), and resting blood pressure (BP) were completed. CRF (VO2 peak) was estimated using an individually calibrated treadmill protocol. Habitual MVPA and ST were assessed using an individually calibrated accelerometer protocol. Clustered cardiometabolic risk scores were calculated using blood markers, FMD (%), BP and anthropometric measures. Participants were classified as active (≥60 min MVPA) or inactive and as fit or unfit. Multivariate analysis of covariance (MANCOVA) was used to investigate differences in cardiometabolic risk, BMI Z-score, CRF, and ST by activity status. MANCOVA was also completed to assess differences in cardiometabolic risk, MVPA, ST, and BMI Z-score by fitness status.

RESULTS

Inactive children exhibited significantly higher clustered cardiometabolic risk scores and ST, and lower CRF than active children. Unfit participants exhibited significantly higher clustered cardiometabolic risk scores, BMI Z-scores and ST and lower MVPA in comparison to fit participants.

CONCLUSIONS

This study highlights the importance of children achieving 60 min MVPA daily and provides further evidence surrounding the importance of CRF for health.

Obesity impairs vasodilatation and blood flow increase mediated by endothelial nitric oxide: an overview

Obesity dramatically increases the risk of development of cardiovascular and metabolic diseases. Endothelial dysfunction induced by obesity is an important risk factor that impairs blood flow controls in various organs. Impaired endothelial function occurs early in life in obese children. Obesity-induced endothelial dysfunction is associated with decreased nitric oxide (NO) production due to impaired endothelial NO synthase activity and expression and increased production of superoxide anion and the endogenous NOS inhibitor ADMA, together with increased vasoconstrictor factors, such as endothelin-1 and sympathetic nerve activation. Decreased endothelial progenitor cells are also involved in endothelial cell senescence in obese individuals. Insulin resistance and diabetes mellitus augment obesity-induced endothelial dysfunction. Adipokines liberated from adipose tissues play roles in modulating endothelial function; adiponectin and ghrelin have beneficial effects on endothelial cells. Effects of leptin on endothelial function are controversial. Decreased body weight by physical exercise, dietary interventions, and bariatric surgery are effective measures that reverse endothelial dysfunction; however, the weight control is not only the reason for improving of endothelia function. Pharmacological therapies with β-adrenoceptor antagonists, resveratolol, anti-obesity agents, nifedipine, and NADPH oxidase inhibitors may also be effective; however, these treatments have to be utilized under the basis of exercise and dietary controls.

The effect of exergaming on vascular function in children

OBJECTIVES

To assess whether exergaming can induce measurable changes in heart rate (HR), energy expenditure (EE), and flow-mediated dilation (FMD) arterial function in healthy children.

STUDY DESIGN

Fifteen children (8 males, 10.1 ± 0.7 years, body mass index 17.9 ± 2.4 kg.m(-2)) undertook a graded exercise test and 2 × 15 minute exergaming sessions (Xbox 360-Kinect); high intensity exergaming (HiE, Kinect Sports-200 m Hurdles) and low intensity exergaming (LoE, Kinect Sports-Ten Pin Bowling). Brachial artery FMD, a measure of endothelial function and arterial health, was measured before and immediately after each exergaming intervention. Actihearts were used to measure EE and HR during game play and a physical activity enjoyment scale assessed enjoyment.

RESULTS

Average HR during HiE (146 ± 11 beats per minute) was greater than during LoE (104 ± 11 beats per minute, P < .05), a pattern reinforced by EE data (HiE 294.6 ± 75.2 J.min(-1).kg(-1), LoE 73.7 ± 44.0 J.min(-1).kg(-1), P < .05). FMD decreased after HiE (P < .05), whereas no change was observed following LoE. Subjects reported no differences in enjoyment between LoE and HiE.

CONCLUSION

HiE, but not LoE, induced large HR and EE responses that were associated with effects on vascular function. This study suggests that an acute bout of HiE exergaming may provide a substrate for beneficial arterial adaptations in children.

Achieving long-term weight maintenance in Mexican-American adolescents with a school-based intervention

PURPOSE

This study evaluated 24-month outcomes of a school-based intensive lifestyle weight management program targeting overweight Mexican-American adolescents.

METHODS

We recruited a total of 71 adolescents (32 males; 45.1%) between the ages of 10 and 14 years, at or above the 85th percentile for body mass index (BMI). Participants were randomized to a 6-month instructor-led intervention (ILI) or a self-help (SH) program. Both interventions were aimed at modifying eating and physical activity behaviors using behavior modification strategies. We assessed changes in participants' standardized BMI and BMI percentile at baseline, 1, and 2 years.

RESULTS

Repeated-measures analyses showed that ILI participants showed significantly greater decreases in standardized BMI at 1 and 2 years (F = 8.58, p < .01; and F = 9.27, p < .01, respectively) compared with SH controls. Similar results were found for changes in BMI and BMI percentile. At 2 years, the ILI condition decreased their average BMI percentile by 3.9 percentile points, compared to an increase of 1.6 percentile points in the SH condition.

CONCLUSIONS

A school-based intervention resulted in improved weight outcomes in overweight Mexican-American adolescents and results were maintained over 2 years.

Vascular transcriptional alterations produced by juvenile obesity in Ossabaw swine

We adopted a transcriptome-wide microarray analysis approach to determine the extent to which vascular gene expression is altered as a result of juvenile obesity and identify obesity-responsive mRNAs. We examined transcriptional profiles in the left anterior descending coronary artery (LAD), perivascular fat adjacent to the LAD, and descending thoracic aorta between obese (n = 5) and lean (n = 6) juvenile Ossabaw pigs (age = 22 wk). Obesity was experimentally induced by feeding the animals a high-fat/high-fructose corn syrup/high-cholesterol diet for 16 wk. We found that expression of 189 vascular cell genes in the LAD and expression of 165 genes in the thoracic aorta were altered with juvenile obesity (false discovery rate ≤ 10%) with an overlap of only 28 genes between both arteries. Notably, a number of genes found to be markedly upregulated in the LAD of obese pigs are implicated in atherosclerosis, including ACP5, LYZ, CXCL14, APOE, PLA2G7, LGALS3, SPP1, ITGB2, CYBB, and P2RY12. Furthermore, pathway analysis revealed the induction of proinflammatory and pro-oxidant pathways with obesity primarily in the LAD. Gene expression in the LAD perivascular fat was minimally altered with juvenile obesity. Together, we provide new evidence that obesity produces artery-specific changes in pretranslational regulation with a clear upregulation of proatherogenic genes in the LAD. Our data may offer potential viable drug targets and mechanistic insights regarding the molecular precursors involved in the origins of overnutrition and obesity-associated vascular disease. In particular, our results suggest that the oxidized LDL/LOX-1/NF-κB signaling axis may be involved in the early initiation of a juvenile obesity-induced proatherogenic coronary artery phenotype.

Assessment of endothelial dysfunction in childhood obesity and clinical use

The association of obesity with noncommunicable diseases, such as cardiovascular complications and diabetes, is considered a major threat to the management of health care worldwide. Epidemiological findings show that childhood obesity is rapidly rising in Western society, as well as in developing countries. This pandemic is not without consequences and can affect the risk of future cardiovascular disease in these children. Childhood obesity is associated with endothelial dysfunction, the first yet still reversible step towards atherosclerosis. Advanced research techniques have added further insight on how childhood obesity and associated comorbidities lead to endothelial dysfunction. Techniques used to measure endothelial function were further brought to perfection, and novel biomarkers, including endothelial progenitor cells, were discovered. The aim of this paper is to provide a critical overview on both in vivo as well as in vitro markers for endothelial integrity. Additionally, an in-depth description of the mechanisms that disrupt the delicate balance between endothelial damage and repair will be given. Finally, the effects of lifestyle interventions and pharmacotherapy on endothelial dysfunction will be reviewed.

Puberty and microvascular function in healthy children and adolescents

OBJECTIVE

To determine the role of pubertal status on microvascular function in healthy children and adolescents.

STUDY DESIGN

Children and adolescents (n = 112; age 10-16 years) were investigated in 2 separate prospective cross-sectional studies. The main outcome measure was microvascular function, assessed by peripheral arterial tonometry to determine the reactive hyperemic index (RHI). Physical activity was assessed using 7-day recall in one study and accelerometry in the other study. Subjects were grouped based on their self-assessed pubertal status according to Tanner stage: group 1 (prepuberty, Tanner I), group 2 (mid-puberty, Tanner II/III), and group 3 (late puberty, Tanner IV/V). Stepwise multiple regression analysis was performed to identify independent predictors of the RHI.

RESULTS

Complete data were available for 94 subjects (55 females) with a median (IQR) age of 14 (3.0) years and a mean body mass index of 19.0 ± 3.63 kg·m(-2). Significant correlations with RHI were observed for Tanner stage (r = 0.569; P < .001), age (r = 0.567; P < .001), stature (r = 0.553; P < .001), systolic blood pressure (r = 0.494; P < .001), and body mass index (r = 0.309; P = .001), but not for sex and moderate-to-vigorous physical activity. In stepwise regression analysis, pubertal status was the only independent predictor of microvascular function (R(2) = 0.242; β = 0.492; P < .001). Prepubertal children (group 1) had a significantly lower RHI [1.14 (0.24)] compared with group 2 [1.65 (0.57)] and group 3 [1.70 (0.75)] (all P < .001).

CONCLUSION

Pubertal status was the main predictor of microvascular function in healthy children and adolescents. Future studies investigating microvascular function in this age group should assess and control for pubertal maturation.

Variação do diâmetro da artéria braquial em crianças obesas: presente e futuro

OBJETIVO: Revisão da literatura acerca do uso da medida da variação do diâmetro da artéria braquial por ultrassonografia de alta resolução (dilatação mediada por fluxo) como preditor de risco para doença cardiovascular em crianças e adolescentes obesos. FONTES DE DADOS: Levantamento de publicações indexadas no Medline/PubMed de trabalhos publicados entre 2002 e 2011, rastreadas com a combinação dos descritores: "endothelium", "child", "ultrasonography" e "obesity", além de estudos e textos clássicos sobre o tema. Foram encontradas 54 publicações e 32 delas foram incluídas na presente revisão do tema. SINTESE DOS DADOS: O estudo da disfunção endotelial tem sido empregado como preditor de risco para doenças cardiovasculares, tais como aterosclerose e doença cardíaca coronariana, visto que a lesão endotelial é um importante evento na fisiopatologia de tais doenças. CONCLUSÕES: A dilatação mediada por fluxo da artéria braquial mostra-se importante como ferramenta diagnóstica e prognóstica na avaliação da função endotelial de crianças e adolescentes com excesso de peso por ser um método não invasivo, com boa aplicabilidade quanto ao custo, à inocuidade e ao benefício.

Changes in cardiorespiratory fitness in 9- to 10.9-year-old children: SportsLinx 1998-2010

PURPOSE

The study's purposes were to 1) assess changes in cardiorespiratory fitness (CRF) from 1998 to 2010, controlling for decimal age and body mass index (BMI), and 2) repeat the analysis in cohorts from 2005 to 2010, controlling for maturation, deprivation, and BMI.

METHODS

A total of 27,942 (n = 14,247 boys) 9- to 10.9-yr-old participants from one UK city were included in this serial cross-sectional study from 1998-1999 to 2009-2010. An indices of multiple deprivation (IMD) score was assigned to each participant on the basis of home postcode. Stature, sitting stature, and body mass were estimated. BMI and somatic maturity were calculated. Performance on the 20-m multistage shuttle run test (20mSRT) was used to estimate CRF (total shuttles). One-way ANCOVAs were completed to assess temporal trends in CRF, separately by sex. Model 1 assessed changes from 1998 to 2010 and included decimal age and BMI as covariates. Model 2 assessed changes from 2005 to 2010 and included maturity, IMD, and BMI as covariates.

RESULTS

Results indicate that 20mSRT performance has declined in UK schoolchildren. An annual decline of 1.34% and 2.29% was observed in boys and girls, respectively. In model 1, for boys, the baseline cohort performed better than all other groups with the exception of the 1999-2000 group. For girls, declines in 20mSRT performance were observed from 2003 onward. In model 2, for boys, the 2007-2008 and 2008-2009 cohorts completed fewer 20mSRT shuttles than all other groups. For girls, the 2007-2008 and 2008-2009 cohorts also performed worse than all other years.

CONCLUSIONS

The decline in CRF suggests children in the more recent SportsLinx cohorts may be at an increased risk of cardiometabolic illness in comparison with earlier cohorts. The promotion of vigorous physical activity is urged to promote CRF in children.

Arterial structure and function in ambulatory adolescents with cerebral palsy are not different from healthy controls

Physical inactivity in youth with cerebral palsy (CP) places them at increased risk of developing cardiovascular disease. The current study assessed indices of arterial health in adolescents with CP, classified as levels I-II of the Gross Motor Function Classification System (GMFCS) (n = 11, age 13.2 ± 2.1 yr), in comparison to age- and sex-matched controls (n = 11, age 12.4 ± 2.3 yr). Groups were similar in anthropometric measurements, resting blood pressures, and heart rates. There were no group differences in brachial flow-mediated dilation (11.1 ± 7.8 versus 6.1 ± 3.6), carotid intima-media thickness (0.42 ± 0.04 versus 0.41 ± 0.03 mm), and distensibility (0.008 ± 0.002 versus 0.008 ± 0.002 mmHg) or central (4.3 ± 0.6 versus 4.1 ± 0.9 m/s) and peripheral pulse wave velocity (7.1 ± 1.7 versus 7.6 ± 1.1 m/s); CP versus healthy controls, respectively. Vigorous intensity physical activity (PA) was lower in the CP group (CP: 38 ± 80 min versus controls: 196 ± 174 min); groups were similar in light and moderate intensity PA levels. Arterial health of ambulatory youth with CP is not different from a control group despite lower vigorous PA levels. Similar studies need to examine individuals with more pronounced mobility limitations (GMFCS level III–V).

Blood Pressure Control at Rest and during Exercise in Obese Children and Adults

The hemodynamic responses to exercise have been studied to a great extent over the past decades, and an exaggerated blood pressure response during an acute exercise bout has been considered as an indicator of cardiovascular risk. Obesity is a major factor influencing the blood pressure response to exercise since evidence indicates that the arterial pressure response to exercise is exacerbated in obese compared with lean adults. Signs of augmented responses (such as an exaggerated blood pressure response) to physical exertion appear early in life (from the prepubertal years) in obese individuals. Understanding the mechanisms that drive the altered hemodynamic responses during exercise in obese individuals and prevent the progression to hypertension is vitally important. This paper focuses on the evidence linking obesity with alterations of the autonomic nervous system and discusses the potential mechanisms and consequences of the altered sympathetic nervous system behavior in obese individuals at rest and during exercise. Furthermore, this paper presents the alterations in the reflex regulatory mechanisms ("exercise pressor reflex" and baroreflex) in obese children and adults and addresses the effects of training on obesity-related disturbances.