Paths towards a healthier BMI among short and adequate sleepers: A pathway network analysis considering movement behaviors in low-income preschoolers.

INTRODUCTION: Short sleep duration has been seen as a predictor of higher body mass index (BMI) in youth. Sleep duration varies substantially along early childhood, and the paths towards a healthier BMI, considering the other movement behaviors (physical activity-PA and screen time) are unexplored in preschoolers. AIM: To construct a sleep-BMI model to capture the direct and indirect paths to intervening towards a healthier BMI, according to low-income preschoolers' compliance with the other movement behaviors. METHODS: Two hundred and seventy two preschoolers (4.5 ± 0.0; 138 boys) participated in the study. Sleep and screen time (ST) were assessed in a face-to-face interview with primary caregivers. PA was assessed using accelerometer (wGT3X-BT). Preschoolers were categorized as compliant or not with sleep, screen time, total and moderate to vigorous PA recommendations. BMIz-score was calculated according to preschoolers' sex and age. All the assessed variables, besides sex and age were included in a Network Pathway Analysis (NPA) according to age as nodes. RESULTS: At 3 years old, a direct and negative path between sleep-BMIz score was observed. At four and 5 years old, this relationship became positive. Further, girls were more compliant with sleep, ST and total PA recommendations. Total PA (TPA) showed the highest expected influence value in the general, 3 and 4 years old NPA. CONCLUSION: The NPA analysis showed different directions for the relationship between sleep and BMIz score, according to age. Intervention strategies to a healthier BMI among preschoolers compliant or not with sleep recommendations should focus in increasing TPA.

Variations in accelerometry measured physical activity and sedentary time across Europe - harmonized analyses of 47,497 children and adolescents.

BACKGROUND: Levels of physical activity and variation in physical activity and sedentary time by place and person in European children and adolescents are largely unknown. The objective of the study was to assess the variations in objectively measured physical activity and sedentary time in children and adolescents across Europe. METHODS: Six databases were systematically searched to identify pan-European and national data sets on physical activity and sedentary time assessed by the same accelerometer in children (2 to 9.9 years) and adolescents (≥10 to 18 years). We harmonized individual-level data by reprocessing hip-worn raw accelerometer data files from 30 different studies conducted between 1997 and 2014, representing 47,497 individuals (2-18 years) from 18 different European countries. RESULTS: Overall, a maximum of 29% (95% CI: 25, 33) of children and 29% (95% CI: 25, 32) of adolescents were categorized as sufficiently physically active. We observed substantial country- and region-specific differences in physical activity and sedentary time, with lower physical activity levels and prevalence estimates in Southern European countries. Boys were more active and less sedentary in all age-categories. The onset of age-related lowering or leveling-off of physical activity and increase in sedentary time seems to become apparent at around 6 to 7 years of age. CONCLUSIONS: Two third of European children and adolescents are not sufficiently active. Our findings suggest substantial gender-, country- and region-specific differences in physical activity. These results should encourage policymakers, governments, and local and national stakeholders to take action to facilitate an increase in the physical activity levels of young people across Europe.

Adherence to 24-hour movement guidelines among Portuguese preschool children: the prestyle study.

PURPOSE: The 24-Hour Movement Guidelines (24 hMG) provide specific recommendations, including physical activity (PA), screen-time and sleep-duration, which preschoolers should achieve for a healthy day (24 h). The aim of the current study was to analyse preschooler's adherence with the 24-Hour Movement Guidelines. METHODS: The sample comprised 739 preschool children. PA was accelerometer-derived. Screen time and sleep duration were parent-reported through questionnaires. Preschoolers were classified as meeting/not meeting in each guideline and as well as for the overall 24hMG. RESULTS/FINDINGS: According to the 24hMG, we found high percentages of preschoolers that met sleep guidelines (80.6%), only around 1/3 of preschool children met PA (28.6%) and a lower proportion met screen-time guidelines (20.3%). We found that 31.7% of the children met at least 2 of the recommendations and that more than half only one (52.8%). Overall, 4.5% of preschool children complied with the 24hMG and 11.1% of the children did not comply with any of the three recommendations. CONCLUSIONS: Few preschoolers met PA and screen-time recommendations, which deeply impacts the preschooler's adherence to the 24hMG. Future work should focus on finding solutions for promoting better adherence and mainly identifying ways to reduce screen time and increase PA at these ages.

Relationship Among Changes in Sedentary Time, Physical Activity, and Body Mass Index in Young Schoolchildren: A 3-Year Longitudinal Study.

PURPOSES: To examine the association between sedentary time (ST) and light physical activity (LPA), moderate- to vigorous-intensity physical activity (MVPA), and body mass index (BMI), and to track these behaviors over a 3-year follow-up in young schoolchildren. METHODS: The final sample was 64 children (female: n = 36 or 56.3%), enrolled in schools in Porto, Portugal. Height and mass of children were measured by standard methods, and BMI was then calculated. ST, LPA, and MVPA were measured by accelerometer. Changes (Δ) and relative changes (Δ%) between 2009/2010 and 2012/2013 of ST, LPA, MVPA, and BMI were computed. Multiple linear regression analyses were fit to predict Δ%ST (outcome variable), by Δ%LPA, Δ%MVPA, and Δ%BMI (exposure variables). RESULTS: ST increased and LPA decreased significantly for whole sample (both Ps < .05). No statistically significant difference was found for MVPA over time. There were no differences for ΔST, ΔLPA, ΔMVPA, and ΔBMI between boys and girls. The Δ%LPA and Δ%MVPA were negatively associated with Δ%ST, whereas Δ%BMI was positively associated. Tracking coefficients varied from moderate to strong. CONCLUSIONS: Time spent in ST increases due to displacement of time in LPA. This reinforces public health measures and suggests the need for interventions focusing on offsetting the decline ST and increasing MVPA during childhood.

Motor fitness and preschooler children obesity status.

The aim of this study was to examine the association between motor fitness (MF) and obesity status in preschool children. The sample comprised 467 children aged 3-6 years. Preschool children body mass index was classified according to International Obesity Task Force and categorised into three levels, normal, overweight and obesity. Total physical activity was assessed by accelerometer and MF test was assessed through two MF tests 10 × 5m shuttle run test (SRT) and a 7 m jumping distance on 2 feet test (J2F). Low MF was considered for MF if SD above 1. A single variable with three categories was created: low MF medium MF and high MF. The prevalence of normal weight, overweight and obesity was 67.6%, 22.7% and 9.7%, respectively. The prevalence of SD > 1 for SRT was 13.7% and 14.4% for J2F, for single variable was 19.2%. Multinomial logistic regression analysis showed that obese preschoolers were more likely six times classified as having low MF level than their non-overweight counterparts (OR: 6.4; IC: 1.3-36.6). This study showed a considerable prevalence of overweight and obesity among preschoolers. Obesity has already been associated with lower MF. Further longitudinal studies are needed to confirm this data.

Association between sedentary behavior time and waist-to-height ratio in preschool children.

OBJECTIVES: To explore the association between sedentary behavior time (SB), and waist-to-height ratio (WHtR) in preschool children. METHODS: This study included 646 preschool children (4- to 6-years old). WHtR was calculated as the ratio of waist/height with a cutoff of 0.5 used to define risk of abdominal obesity. Sedentary behavior was measured during 7 consecutive days by accelerometer. Logistic regression was used to determine the association between SB and WHtR. RESULTS: The prevalence of central obesity (WHtR) was 52.4 and 39.2% for girls and boys, respectively. Boys classified as being at risk for central obesity were more likely to spend more time in SB (OR: 1.6; CI: 1.1-2.5; P ≤ 0.05), adjusted by age (P ≤ 0.001). CONCLUSIONS: Our data suggested that boys classified as having higher SB were more likely to having more central obesity. Am. J. Hum. Biol. 28:746-748, 2016. © 2016 Wiley Periodicals, Inc.

Effects of 6-month soccer and traditional physical activity programmes on body composition, cardiometabolic risk factors, inflammatory, oxidative stress markers and cardiorespiratory fitness in obese boys.

Physical activity is important in obesity prevention, but the effectiveness of different physical activity modalities remains to be determined among children. The main purpose of this study was to compare the effects of a 6-month soccer programme and a traditional physical activity programme on changes in body composition, cardiometabolic risk factors, inflammatory and oxidative markers, cardiorespiratory fitness and perceived psychological status in obese boys. Eighty-eight boys (8-12 years; BMI > +2 standard deviations of WHO reference values) participated in one of three groups: soccer, traditional activity and control. Soccer and traditional activity programmes involved 3 sessions per week for 60-90 min at an average intensity of 70-80% of maximal heart rate. Control group participated in activities of normal daily living. All boys participated in school physical education, two sessions per week of 45-90-min. Measurements were taken at baseline and after 6 months, and included body size and composition, cardiometabolic risk factors, inflammatory and oxidative markers, cardiorespiratory fitness and perceived psychological status. Physical activity and dietary intake were assessed before and immediately following the intervention. The three groups had similar characteristics at baseline. After 6 months, both intervention groups had significantly lower relative fatness (% fat), waist circumference and total cholesterol, and higher cardiorespiratory fitness, self-esteem, perceived physical competence and attraction to physical activity compared with control group. In conclusion, physical activity interventions over 6 months positively influenced several indicators of health status among obese boys. The results also suggested that soccer has the potential as an effective tool for the prevention and reduction of childhood obesity and associated consequences.

Physical Activity, Obesity Status, and Blood Pressure in Preschool Children.

OBJECTIVE: To examine the combined effects of physical activity and weight status on blood pressure (BP) in preschool-aged children. STUDY DESIGN: The sample included 733 preschool-aged children (49% female). Physical activity was objectively assessed on 7 consecutive days by accelerometry. Children were categorized as sufficiently active if they met the recommendation of at least 60 minutes daily of moderate-to-vigorous physical activity (MVPA). Body mass index was used to categorize children as nonoverweight or overweight/obese, according to the International Obesity Task Force benchmarks. BP was measured using an automated BP monitor and categorized as elevated or normal using BP percentile-based cut-points for age, sex, and height. RESULTS: The prevalence of elevated systolic BP (SBP) and diastolic BP was 7.7% and 3.0%, respectively. The prevalence of overweight/obese was 32%, and about 15% of children did not accomplish the recommended 60 minutes of daily MVPA. After controlling for age and sex, overweight/obese children who did not meet the daily MVPA recommendation were 3 times more likely (OR 3.8; CI 1.6-8.6) to have elevated SBP than nonoverweight children who met the daily MVPA recommendation. CONCLUSIONS: Overweight or obese preschool-aged children with insufficient levels of MVPA are at significantly greater risk for elevated SBP than their nonoverweight and sufficiently active counterparts.

Step based physical activity guidelines for preschool-aged children.

OBJECTIVE: Public health organizations recommend that preschool-aged children accumulate at least 3h of physical activity (PA) daily. Objective monitoring using pedometers offers an opportunity to measure preschooler's PA and assess compliance with this recommendation. The purpose of this study was to derive step-based recommendations consistent with the 3h PA recommendation for preschool-aged children. METHOD: The study sample comprised 916 preschool-aged children, aged 3 to 6years (mean age=5.0±0.8years). Children were recruited from kindergartens located in Portugal, between 2009 and 2013. Children wore an ActiGraph GT1M accelerometer that measured PA intensity and steps per day simultaneously over a 7-day monitoring period. Receiver operating characteristic (ROC) curve analysis was used to identify the daily step count threshold associated with meeting the daily 3hour PA recommendation. RESULTS: A significant correlation was observed between minutes of total PA and steps per day (r=0.76, p<0.001). The optimal step count for ≥3h of total PA was 9099 steps per day (sensitivity (90%) and specificity (66%)) with area under the ROC curve=0.86 (95% CI: 0.84 to 0.88). CONCLUSION: Preschool-aged children who accumulate less than 9000 steps per day may be considered Insufficiently Active.

The independent associations of sedentary behaviour and physical activity on cardiorespiratory fitness.

BACKGROUND: During childhood and adolescence, both physical activity (PA) and sedentary behaviour seem to influence cardiorespiratory fitness (CRF); however, the combined association of PA and sedentary behaviour remains to be understood. We analysed the combined association of objectively measured sedentary behaviour and moderate-to-vigorous intensity PA (MVPA) on CRF in Portuguese children and adolescents. METHODS: The sample comprised 2506 Portuguese healthy children and adolescents aged 10-18 years, from a cross-sectional school-based study (2008). PA and sedentary behaviour were assessed with accelerometry. Participants were classified as meeting current PA guidelines for youth versus not meeting, and as low versus high sedentary (according to the median value of sedentary time/day by age and gender), and then grouped as follows: Low active-high sedentary; low active-low sedentary; high active-high sedentary; high active-low sedentary. CRF was assessed with the FITNESSGRAM 20 m shuttle-run test. Binary logistic regression models were constructed to verify the relationship between high CRF and the combined influence of MVPA/sedentary behaviour, adjusting for age, gender, body mass index and accelerometer wear time. RESULTS: Participants classified as high active/low sedentary (OR=1.81; 95% CI 1.21 to 2.69), as well as those classified as low active/low sedentary (OR=1.27; 95% CI 1.01 to 1.61) were more likely to be fit, compared with those from the low-active/high-sedentary group. CONCLUSION: MVPA and sedentary behaviour may act independently in their relation with CRF, and that MVPA levels may not overcome the deleterious influence of high-sedentary time in maximising CRF.

Normative functional fitness standards and trends of Portuguese older adults: cross-cultural comparisons.

This cross-sectional study was designed to develop normative functional fitness standards for the Portuguese older adults, to analyze age and gender patterns of decline, to compare the fitness level of Portuguese older adults with that of older adults in other countries, and to evaluate the fitness level of Portuguese older adults relative to recently published criterion fitness standards associated with maintaining physical independence. A sample of 4,712 independent-living older adults, age 65-103 yr, was evaluated using the Senior Fitness Test battery. Age-group normative fitness scores are reported for the 10th, 25th, 50th, 75th, and 90th percentiles. Results indicate that both women and men experience age-related losses in all components of functional fitness, with their rate of decline being greater than that observed in other populations, a trend which may cause Portuguese older adults to be at greater risk for loss of independence in later years. These newly established normative standards make it possible to assess individual fitness level and provide a basis for implementing population-wide health strategies to counteract early loss of independence.

A school-based physical activity intervention in primary school: effects on physical activity, sleep, aerobic fitness, and motor competence.

Objective: The "Super Quinas" project evaluated the effectiveness of an intervention program to improve physical activity, aerobic fitness, sleep, and motor competence on children in primary school. Methods: The experimental group (n = 19) enrolled in a 12-week intervention program (one more extra-curricular activity class of 60 min per week) compared to the CG (n = 19), all aged 9-10 years. Physical activity (PA) and sleep were measured by accelerometry, and aerobic fitness was measured by Children's Yo-Yo test (YYIR1C) during the 1st week (PRE), the 6th week (DUR), and the 12th week (POST) of the intervention program. Motor Competence in PRE and POST intervention was also assessed by the Motor Competence Assessment (MCA) instrument. Heart rate (HR, assessed using HR monitors), and enjoyment level were recorded during all intervention program classes. A linear mixed model analysis (i.e., within-subject analyses) was performed. Results: Comparing the EG and CG in DUR and POST, the EG spent ~18 min and ~ 34 min more time in moderate to vigorous physical activity (MVPA) per day (p < 0.001); had ~44 min and ~ 203 min less sedentary time per day (p < 0.001); performed more 44 and 128 m in the Children's Yo-Yo test compared to CG (p < 0.001) and slept more 17 and 114 min per night (p < 0.001). In POST motor competence was significantly better (27%) in the EG compared to CG (p < 0.001). The %HRmax during the extra-curricular classes ranged between 65 and 81% (i.e., light to moderate intensities), and the enjoyment between fun and great fun. Conclusion: Our findings suggest that adding one more extra-curricular activity class of 60 min per week for 12 weeks effectively increased the levels of physical activity, aerobic fitness, sleep duration, and motor competence in children aged 9-10 years.

Cross validation of ROC generated thresholds for field assessed aerobic fitness related to weight status and cardiovascular disease risk in Portuguese young people.

OBJECTIVES: To examine the efficacy of aerobic fitness thresholds in predicting weight status and cardiovascular disease risk (CVD) in young people. METHODS: A cross-sectional school-based study was conducted on 414 Portuguese young people (235 girls and 179 boys) aged 10-16 years (Mean age ± SD = 13.6 ± 1. 8 years). Height and mass were assessed to determine body mass index (BMI). The 20 m multistage shuttle-fitness test (MSFT) was used as an estimate of aerobic fitness. Capillary blood sampling was used to determine: total cholesterol, triglycerides, high-, and low-density lipoprotein. These were combined with measures of systolic blood pressure as z-scores and summed to create a CVD risk score. RESULTS: Analysis of covariance, controlling for sexual maturation, indicated a significant main effect for BMI as a result of fitness category (P = 0.0001). When applied to CVD risk data, there was no difference between "fit" and "unfit" groups (P = 0.136). Subsequent receiver operating curve (ROC) analysis indicated significant diagnostic accuracy of 20 mMSFT performance for boys and girls (both P = 0.0001) with subsequent cut-offs of estimated VO2 peak of 49.5 ml kg(-1) min(-1) for girls and 47.7 ml kg(-1) min(-1) for boys. When applied to BMI and CVD risk data, there was a significant main effect as a result of fitness category for BMI (P = 0.0001) and CVD risk score (P = 0.0001). CONCLUSIONS: Recently established cut-points proposed by Boddy et al. (Boddy et al. [2012]: PLoS One 7(9): e45755) show validity in distinguishing between weight status but not CVD risk in Portuguese young people. Alternative ROC generated cut points significantly predicted BMI and CVD risk in this sample.

Associations between body mass index, waist circumference and body shape index with resting blood pressure in Portuguese adolescents.

BACKGROUND: Elevated blood pressure (BP) in childhood and adolescence is associated with overweight and obesity. Recently a body shape index (ABSI) has been suggested as superior to body mass index (BMI, kg/m(2)) and waist circumference (WC) as a measure of disease risk. OBJECTIVE: To examine the association between ABSI, BMI, WC and BP in Portuguese adolescents and to consider the role of ABSI, BMI and WC when examining this issue in adolescents. METHODS AND PROCEDURES: Height, body mass, WC and resting blood pressure were assessed in 445 Portuguese adolescents (252 girls and 193 boys) aged 10-17 years. RESULTS: ABSI, BMI and WC were all significantly related to both SBP and DBP (all p = 0.001 or better). ABSI, BMI and WC were all significant predictors of SBP and DBP for the whole sample and when analysed in separate gender groups (p = 0.001 or better in all cases). However, in all cases ABSI was a better predictor of BP than BMI or WC. CONCLUSIONS: Although BMI and WC significantly predict resting BP in adolescents, the use of ABSI explained a greater amount of the variance in BP in this population. When examining the effect of weight status on BP, researchers should consider use of ABSI alongside BMI.

Cardiorespiratory fitness and TV viewing in relation to metabolic risk factors in Portuguese adolescents.

BACKGROUND: The purpose of this study was to examine whether adolescents who have high levels of cardiorespiratory fitness (CRF) co-existing with low levels of television (TV) viewing present a better metabolic risk profile compared to their low fit and high TV viewing counterparts. SUBJECTS AND METHODS: A total of 372 students (aged 12-15 years old) comprised the sample of this study. Anthropometric data (body mass index and waist circumference) was collected. CRF was calculated based upon the 20 metres shuttle run test. A questionnaire was used to estimate weekly TV viewing. Information about biological maturity and parental education was collected. Participants were then categorized into one of four category profiles according to the scores they achieved: low TV-Fit; high TV-Fit; low TV-Unfit and high TV-Unfit. Metabolic risk score (MRS) was calculated based on the sum of the Z-scores of all the metabolic variables analysed. RESULTS: Logistic regression analyses indicated that the high TV-Unfit group was almost 3-times more likely to be assigned to the high MRS group (OR = 2.85, 95% CI = 1.08-7.50) compared to their low TV-Fit group counterparts. CONCLUSIONS: The data showed that the high TV-Unfit group was associated with an increased metabolic risk in adolescents after adjustment for gender, age, biological maturity and parental education.

Effects of "Football and Nutrition for Health" program on body composition, physical fitness, eating behaviours, nutritional knowledge, and psychological status among 7 to 10 years school children.

Introduction: Noncommunicable diseases and obesity are between the major health threat due to consumption of unhealthy foods and limited time spent on physical activities, a situation of particular concern among children. Since children spend most of their time at school, this study intends to investigate the effect of a school intervention program, which combines recreational football and nutrition education, on body composition, physical fitness, physical activity, blood pressure and heart rate, eating behaviours, nutritional knowledge, and psychological status in elementary school children. Methods: A total of 67 children, between 7 and 10 years old, were allocated into three groups: the Football Group (FG) which held 2 weekly sessions of 60 min of recreational football, the Nutrition and Football Group (NFG) which held 2 sessions per week of 60 min of recreational football plus 60 min of nutritional education and the Control Group (CG) which maintained its usual curriculum. The intervention lasted 12 weeks. All measurements were collected before and after the intervention. Results: Intervention groups significantly (p < 0.05) improved BMI Z-score, rest heart rate, horizontal jump and shuttle test, physical activity level, and psychosocial health. The NFG group significantly decreased (p < 0.05) waist-to-height ratio and blood pressure, and significantly increased (p < 0.05) nutritional knowledge, fruit, and fish consumption. While FG significantly decreased (p < 0.05) the percentage of fat mass and significantly increased (p < 0.05) muscle mass and performance in the 20 m sprint. Discussion: The results have shown to improve nutritional status, explosive strength, aerobic and neuromuscular fitness, as well as increase the level of physical activity. The nutritional education sessions contributed to increase nutritional knowledge and to improve the consumption of healthy food groups in a ludic-educational way. The "Football and Nutrition for Health" program was able to induce short-term improvements in several health markers, highlighting the role of the school curriculum in children's health.

Metabolic syndrome, physical activity and cardiac autonomic function.

BACKGROUND: Our primary aim was to investigate the associations that components of metabolic syndrome and physical activity have with cardiac autonomic nervous system activity as estimated by heart rate variability (HRV) in young adults free of metabolic abnormalities. We also aimed to identify predictors of 3-year changes in HRV. METHODS: Physical activity was assessed annually in 163 healthy participants over 3 years (2008-2010). Components of metabolic syndrome measured annually were; waist circumference, systolic blood pressure, high-density lipoprotein, triglycerides, glucose, and C-reactive protein. A linear mixed regression model was used to assess associations between HRV, metabolic syndrome components and physical activity. Linear regression was used to identify predictors of changes in HRV. RESULTS: Metabolic syndrome components were negatively associated with HRV indices and higher heart rate, while physical activity was associated with higher HRV and lower heart rate. Physical activity and inflammation were predictors of positive and negative changes in HRV indices, respectively. CONCLUSIONS: In participants without significant metabolic abnormalities, metabolic syndrome components were still associated with less favourable HRV profiles. Physical activity and inflammation were both able to predict changes in HRV, albeit in different directions. It appears that the process of autonomic dysfunction starts at a young age and may be mediated in part by inflammation. Metabolic syndrome prevalence is increasing in younger populations; promoting the metabolic and autonomic benefits of exercise remains imperative.

Waist circumference percentiles for Portuguese children and adolescents aged 10 to 18 years.

UNLABELLED: The purposes of this study were to develop age- and sex-specific waist circumference reference data for Portuguese children and adolescents aged 10-18 years and to compare them with those from other countries. This was a school-based study performed in Portugal. A total of 22,003 children and adolescents aged 10-18 years were included in the study. Smoothed sex- and age-specific 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentile curves of waist circumference were estimated using Cole's lambda-mu-sigma method. Waist circumference values increased with age in both boys and girls, and boys had higher values than girls at every age and percentile. In both sexes, the Portuguese values in the 90th percentile were closer to the Bolivian values and considerably lower than those of the American children for all age groups. CONCLUSION: The data presented provide information for abdominal risk assessment and clinical and lifestyle intervention; our results also provide useful baseline data information for the implementation of a surveillance system required to monitor trends and factors associated with abdominal obesity in children and adolescents.

Comparisons between inverted body mass index and body mass index as proxies for body fatness and risk factors for metabolic risk and cardiorespiratory fitness in Portuguese adolescents.

OBJECTIVES: To compare inverted body mass index (iBMI, cm(2) /kg) and body mass index (BMI, kg/m(2) ) as predictors of body fatness, metabolic risk, and cardiovascular fitness in adolescents. METHODS: A cross-sectional school-based study was conducted on 445 Portuguese adolescents (252 girls and 193 boys) aged 10-17 years. Height and body mass were assessed to determine iBMI and BMI, percent body fatness was determined from skinfold measures (tricep, subscapular) using the Slaughter et al. (1988: Hum Biol 60: 709-723) regression equation and cardiorespiratory fitness (CRF) was assessed using the 20-m shuttle run test. Capillary blood sampling was used to determine: Total cholesterol, triglycerides, high, and low density lipoprotein. These were combined with measures of systolic blood pressure and waist circumference as z-scores. Metabolic risk (MRS) was constructed by summing the z-scores. RESULTS: iBMI and BMI were both significantly related to percent body fatness, CRF and MRS (all P = 0.005 or better). BMI was not normally distributed (P = 0.0001), whereas iBMI was (P > 0.05). Regression analysis identified that iBMI and BMI, both alongside for age, were significant predictors of percent body fatness, CRF and MRS (all P = 0.005 or better). Compared with BMI, iBMI was a similar predictor of CRF, MRS and body fatness. CONCLUSIONS: iBMI offers a biologically sound alternative to BMI to assess the effect of weight status on MRS and CRF in adolescents and allows appropriate use of parametrical statistical techniques without changing the conclusions drawn from such data.

Influence of body fat and level of physical activity on rate-pressure product at rest in preschool children.

OBJECTIVE: The rate-pressure product (RPP) has strong correlation with the maximal oxygen consumption and is an indicator of myocardium stress being considered as the best indirect method to measure myocardial oxygen consumption. However, to the best of our knowledge, no studies have addressed in preschool children. The aim of this study was to analyze the influence of percentage of body fat (%BF) and physical activity (PA) patterns on RPP at Rest (RPPrest) as a marker of cardiac load in Preschool children. METHODS: The study comprised 593 preschool children aged 3-6 years-old. Heart rate (HR), systolic (SBP), and diastolic (DBP) blood pressure were taken at rest. The RPP was then calculated. The %BF was estimated from four skinfolds thicknesses and PA was assessed during 7 consecutive days by accelerometry. RESULTS: Our data showed that only %BF (P ≤ 0.001) and vigorous PA (P ≤ 0.05) contributed significantly toward RPPrest variation. However, the multivariate analysis showed that only %BF (P ≤ 0.05) had a significant influence on RPPrest variation. CONCLUSION: These findings suggest that on preschoolers there is an association between RPP at rest and %BF.