Factors Affecting the Body Mass Index in Adolescents in Portuguese Schools

The prevalence of overweight and obesity among children is increasing; hence, it was aimed to assess the Body Mass Index (BMI) in school children aged from 10 to 18 years for girls and to 17 for boys, as well as to identify the factors influencing BMI. This study included 742 students who answered a questionnaire previously approved for application in schools. The results showed some sociodemographic factors associated with BMI classes: age, school year, practicing high competition sport, being federate in a sport or having a vegetarian diet. The educational factors associated with BMI classes included only seminars given at school by a nutritionist. Behavioural factors significantly associated with BMI included: learning in classes, playing in the open air, reading books or use of internet. As conclusion, the results demonstrated that several factors affect BMI, and hence some actions could be taken in order to change them so as to reduce the prevalence of overweight, namely reinforcing the role of school and a more active participation of nutritionists in the education of the adolescents.

Natural ventilation and indoor air quality in educational buildings: experimental assessment and improvement strategies

Indoor environmental conditions in classrooms, in particular temperature and indoor air quality, influence students’ health, attitude and performance. In recent years, several studies regarding indoor environmental quality of classrooms were published and natural ventilation proved to have great potential, particularly in southern European climate. This research aimed to evaluate indoor environmental conditions in eight schools and to assess their improvement potential by simple natural ventilation strategies. Temperature, relative humidity and carbon dioxide concentration were measured in 32 classrooms. Ventilation performance of the classrooms was characterized using two techniques, first by fan pressurization measurements of the envelope airtightness and later by tracer gas measurements of the air change rate assuming different envelope conditions. A total of 110 tracer gas measurements were made and the results validated ventilation protocols that were tested afterward. The results of the ventilation protocol implementation were encouraging and, overall, a decrease on the CO2 concentration was observed without modifying the comfort conditions. Nevertheless, additional measurements must be performed for winter conditions.