Physical activity around the clock:objectively measured activity patterns in young children of the GECKO Drenthe cohort

Background: Given the widespread problem of physical inactivity, and the continued growth in prevalence of childhood and adolescent obesity, promotion of regular physical activity (PA) among young people has become a public priority. A greater understanding of children's PA patterns throughout the day is needed to effectively encourage children to be more physically active. Hence this study looking at the distribution of PA in young children throughout the day and its relevance to overweight. Methods: Accelerometers (ActiGraph GT3X, weartime > 600 min/day, >= 3 days) were used to measure the PA of 958 children (aged 5.7 +/- 0.8 years, 52% boys) enrolled in the GECKO Drenthe cohort. Levels of sedentary time (ST), light PA (LPA) and moderate-to-vigorous PA (MVPA) were recorded throughout the day and analysed in segments (07: 00-09:00, 09:00-12:00, 12:00-15:00, 15:00-18:00, 18:00-21:00). Body mass index was measured by Preventive Child Healthcare nurses and Cole's (2012) definition of overweight was used. General linear mixed models, adjusted for age, sex and season, were used to analyse patterns of PA and ST throughout the day. Results: Children were most sedentary in the early morning (07:00-09:00) and evening (18:00-21:00), and exhibited the most time spent engaged in LPA and MVPA in the afternoon (12:00-15:00) and late afternoon (15:00-18:00). The greatest inter-individual variation in ST, LPA and MVPA among the children occurred in the late afternoon and evening (approximately 40, 30 and 15 min difference per time segment between 25th and 75th percentile, respectively). The most active children (highest quartile of MVPA) were found to be more active and less sedentary throughout the entire day than the least active children (lowest quartile of MVPA). Furthermore, children with overweight were no less active than children without overweight. Conclusions: At this young age, the relevance of different PA patterns to childhood overweight was minimal. Children were most active in the afternoon and late afternoon. To encourage PA in general, ST can be reduced and PA increased in the early morning and evening. Targeted PA interventions to specifically stimulate the least active children could take place in the late afternoon or evening

Physical fitness, cognitive functioning and academic achievement in healthy adolescents

Purpose: Examine the association between health-related physical fitness (cardiorespiratory fitness and muscular fitness) and skill-related physical fitness (speed-agility) and both cognitive functions and academic achievement in adolescents (12–15 years). Methods: Data of 423 Dutch adolescents were analyzed (46.8% boys, age = 13.45 ± 0.43 years). Physical fitness was assessed using five subtests of the Eurofit test battery measuring cardiorespiratory fitness (20 m Shuttle Run Test), muscular fitness (Broad Jump and Sit-Ups) and speed-agility (10 × 5 m Shuttle Run Test and Plate Tapping Test). Cognitive functions were assessed by the Digit Span Task, the Grid Task and an adapted version of the Attention Network Test. Finally, academic achievement was assessed by two standardized tests assessing mathematic skills and language skills. Multilevel regression analyses were performed in MlWin to examine the relations of interest adjusting for sex and age. Results: Multilevel regression analysis showed that speed-agility was significantly related to visuospatial working memory (β = 0.159; p = 0.014), information processing and control (β = 0.238; p < 0.001) and interference control (β = 0.156; p = 0.039), but not to the other cognitive or academic achievement outcomes. Cardiorespiratory fitness and muscular fitness were not related to any of the cognitive or academic achievement outcomes. Conclusion: The results suggest that skill-related physical fitness is related to cognitive functions and health-related physical fitness is not. Therefore it can be argued that improved levels of skill-related physical fitness may lead to improved cognitive functioning

Adiposity and High Blood Pressure during Childhood:A Prospective Analysis of the Role of Physical Activity Intensity and Sedentary Time in the GECKO Drenthe Cohort

Whereas in adults, physical inactivity is strongly related to obesity and hypertension, in young children the evidence is inconsistent and scarce. We examined the association between physical activity (PA) behaviours at 5-6 years of age and adiposity and blood pressure (BP) at 10-11 years in 947 children (51% boys) from the Groningen Expert Center for Kids with Obesity (GECKO) Drenthe cohort. Sedentary time (ST) and light, moderate, and vigorous PA were assessed using accelerometry (ActiGraph GT3X, wear time > 600 min/day, >= 3 days). Body mass index (BMI), waist circumference (WC), and systolic and diastolic BP were measured at 5-6 and 10-11 years of age and standardized as age- and sex-adjusted (and height-adjusted, for BP) z-scores. Adjusted linear and logistic regression models showed that most PA behaviours were not related to standardized BMI or WC, overweightness/obesity, abdominal overweightness/obesity, standardized systolic or diastolic BP, pulse pressure, or prehypertension at 10-11 years of age. Only if children spent more time in vigorous PA was WC slightly lower (B (95% CI) = -0.08 (-0.16, -0.01) SD, std beta = -0.068) and the increase in WC over the years was less (B (95% CI) = -0.10 (-0.18, -0.01) SD; std beta = -0.083). To conclude, at this very young age, PA behaviours are not a strong predictor for overweightness/obesity or hypertension later in childhood