The purpose of this study was to summarize the effects of physical activity and exercise on peripheral brain-derived neurotrophic factor (BDNF) in healthy humans. Experimental and observational studies were identified from PubMed, Web of Knowledge, Scopus, and SPORT Discus. A total of 32 articles met the inclusion criteria. Evidence from experimental studies suggested that peripheral BDNF concentrations were elevated by acute and chronic aerobic exercise. The majority of the studies suggested that strength training had no influence on peripheral BDNF. The results from most observational studies suggested an inverse relationship between the peripheral BDNF level and habitual physical activity or cardiorespiratory fitness. More research is needed to confirm the findings from the observational studies.

The objective of the present study was to evaluate the effectiveness of a one-year multi-component immersive day-camp weight-loss intervention for children with overweight and obesity. The study design was a parallel-group randomized controlled trial. One hundred fifteen 11-13-year-old children with overweight and obesity were randomized into either: A six-week day-camp intervention arm focusing on increased physical activity, and healthy diet followed by a subsequent one-year family-based intervention, or a standard intervention arm consisting of one weekly exercise session for six weeks. Body mass index (BMI) was the primary outcome. BMI z-score, clustered cardiovascular risk z-score, and body composition were secondary outcomes. All outcomes were measured at baseline, six week-, and 52 week follow-up. After six weeks, children from the day-camp intervention arm had improved their BMI (-2.2 kg/m2 (95% CI -2.6 to -1.7, P<0.001)) and all secondary outcomes when compared to the children from the standard intervention arm. After 52 weeks, the day-camp intervention arm had a lower BMI (-1.2 kg/m2 (95% CI -1.8 to -0.5, P = 0.001)), and BMI z-score (-0.20 (95% CI -0.35 to -0.05, P = 0.008)), and clustered cardiovascular risk z-score (-0.23 (95% CI -0.37 to -0.08, P = 0.002)) compared to the standard intervention arm. No group differences were detected in body composition after 52 weeks. This study shows that the day-camp intervention arm is effective in reducing BMI and improving the metabolic health of children with overweight and obesity. However, the effects seem to be diminishing over time.

Dette er siste tekst-versjon av artikkelen, og den kan inneholde små forskjeller fra forlagets pdf-versjon. Forlagets pdf-versjon finner du på bjsm.bmj.com: http://dx.doi. org/10.1136/bjsports-2012-091958 This is the final text version of the article, and it may contain minor differences from the journal's pdf version. AbstractObjectives: There is paucity in prospective studies investigating the association between carotid sub-clinical atherosclerosis across childhood. Therefore the aim was investigate the association between physical activity (PA) intensity across childhood and sub-clinical atherosclerosis in adolescence. Study design:This was a prospective study of a sample of 254 children (baseline age 8-10 y) with a six year follow-up. The cumulative exposure and the change in minutes spend in moderate-andvigorous and vigorous PA intensity were measured using the Actigraph activity monitor. Subclinical atherosclerosis progression was expressed as carotid intima thickness (cIMT), carotid arterial stiffness and secondarily as a metabolic risk z-score. The summed z-score included a homoeostasis model assessment score of insulin resistance (HOMA-IR), triglycerides, total cholesterol to high-density lipoprotein ratio, inverse of cardio-respiratory fitness, systolic blood pressure and the sum of four skinfolds. Results:No associations were observed between PA intensity variables and cIMT or carotid arterial stiffness (p>0.05). Neither change in PA intensity nor accumulated minutes of moderate-andvigorous PA intensity was associated to the metabolic risk z-score in adolescence (p>0.05).However, a significant inverse association was observed between accumulated minutes of vigorous PA and the metabolic risk z-score in adolescence independent of gender, and biological maturity (std. beta= -0. 19 p=0.01). Conclusion:Accumulation of or changes in minutes spend at higher PA intensities across childhood was not associated to measures of sub-clinical atherosclerosis in the carotid arteries in adolescence. Our observations suggest that a high volume of vigorous PA across childhood independently associated with lower metabolic CVD risk in adolescence.3

BackgroundIn 2014 the Danish Government introduced a wide-ranging school reform that applies to all public schools in Denmark. The reform involves changes in several aspects of the school structure and content. In a physical activity promotion perspective, a distinctive feature of the school reform is that it has become mandatory to integrate an average of 45 min of daily physical activity in the regular school day. The overarching objective of the PHASAR study is to evaluate the implementation and effect of this ambitious policy-driven physical activity promotion initiative on physical activity and overweight. This paper describes in detail the study protocol.MethodsThe evaluation is divided into a quantitative effect evaluation and a combined quantitative and qualitative process evaluation. A total of 31 schools are enrolled in the PHASAR study including more than 2,000 school-aged children. Objectively measured physical activity data are obtained in the PHASAR study in 2017/18 and compared to repeated cross sectional data collected in four historical school-based studies from 1998 to 2012. Body mass index data from 2012 to 2018 will be collected from The Child Database, which includes repeated cross-sectional assessments on approximately 100,000 children annually. In the absence of a control group, interrupted time-series analysis will be used to evaluate pre- and post-reform physical activity and body mass index levels and trends. A characterization of the school environment for physical activity promotion on a political, environmental, organizational and individual level and school implementation processes will be conducted to evaluate the implementation process. Data will be collected using interviews, surveys, document analyses and observations.DiscussionThe PHASAR study is a rare opportunity to evaluate the effectiveness of a nation-wide policy-driven school-based physical activity promotion initiative. The use of objectively measured pre- and post-reform physical activity and body mass index data combined with a characterization of the school implementation processes for physical activity promotion will provide a comprehensive source to evaluate the school reform. The study findings have the potential to influence national and international policy makers, health professionals and school staff.

BackgroundChildhood overweight has noticeable psychological and social consequences for the child and leads to an increased risk of mortality and morbidity later in life. With the high prevalence of overweight in children and adolescents, it is important to identify effective approaches for the prevention and treatment of overweight in children and young individuals. The primary aim of the study is to assess the effect of an intensive day-camp intervention on body mass index (BMI) in overweight children.MethodsThe Odense Overweight Intervention Study is a semi-blinded randomized controlled trial. Overweight children from the Municipality of Odense, Denmark, were invited to participate in the trial. Based on power calculations 98 participants were found to be sufficient to randomize in order to find an effect of minimum 1.5 BMI points. Gender-stratified concealed block randomization with a ratio of 1:1 and random block sizes of two, four, and six ensured balance between study arms. The intervention consisted of a six-week multi-component day camp including increased physical activity, healthy diet and health education followed by 46 weeks of family-based habitual intervention. The standard care arm was offered two weekly hours of physical activity training for six weeks. The outcomes were measured at baseline and at six-week and 52-week follow-ups. Furthermore, BMI will be assessed again at 48-month follow-up. Test personnel were kept blinded. The intervention effect will be evaluated using mixed model analyses. During 2012 and 2013, 115 children were enrolled in the study. Fifty-nine children were randomized to the day-camp intervention arm and 56 to the standard intervention arm.DiscussionThis study will provide novel information about the long-term health effects of an intense day-camp intervention program on overweight children, due to the design and the follow-up period. Moreover, it will add to the knowledge on designing and implementing feasible camp settings for preventing overweight in children.Trial registrationNCT01574352 at http://clinicaltrials.gov on the 8th of March 2012.