This study investigated the association among loneliness, number of friends, and participation in physical education classes, leisure-time physical activities, and active commuting. Data from 102,072 adolescents participating in the National School–based Health Survey aged 11–19 years were analyzed. Information about the study variables was self-reported through a questionnaire. Adolescents more active in physical education classes and leisure were less likely of having social isolation. Those more active in commuting were more likely of having social isolation. Interventions aimed at addressing social isolation in adolescence can prioritize school and leisure-time physical activities.

The aim of this study was to verify the association between school environment and accumulated physical activity in Brazilian adolescents. This is a study with secondary data from sample 1, from the third edition of the National School Health Survey, a study carried out with 102.072 children and adolescents enrolled in the ninth school grade. Questions about characteristics of the school environment and the offer of opportunities for physical activity practices were addressed, focusing on information regarding the structure for physical activity and about the regular practice of accumulated physical activities. Variables were organized from the structure of schools and opportunities for the practice of physical activities, while accumulated physical activity was used as the outcome variable. Data were analyzed from a binary logistic regression model, organized in crude and adjusted models, with a significance level of 5%. Data were analyzed from SPSS for Windows, version 22.0. Results indicate that, from the adjustment of variables, there was an association between the practice of accumulated physical activity and the existence of a sports court under conditions of use (OR=1.22, 95%CI=1.18-1.26), or presence of courtyard for use of physical education classes (OR=1.04, 95%CI=1.01-1.06). Association between the offer of varied physical activities, except for physical education classes, and the practice of accumulated physical activity (OR=1.05, 95%CI=1.02-1.08) was identified. Existence of a sports court/courtyard in schools and the offer of extracurricular physical activities are associated with the practice of accumulated physical activity in young Brazilian students.

This study aimed to examine the association between physical activity (PA) indicators and TV viewing as a function of the Human Development Index (HDI). Method: This cross-sectional study was based on data from the National School Health Survey, which was composed of 102,072 students (14.28±1.03; 51.3% girls). Total PA, active commuting to school (ACS) and TV viewing were assessed by questionnaires and classified through a gradual scale ranging from "F" (low) to "A+" (high). The correlation between total PA, ACS, TV viewing and HDI was verified by Spearman's Correlation and presented in r s. Results: HDI was positively associated with total PA [girls: r s = 0.572 (p < 0.001); boys: r s = 0.843 (p < 0.001)] and ACS [girls: r s = 0.433 (p < 0.001); boys: r s = 0.554 (p < 0.001)]; while a negative correlation was found between HDI and TV viewing [girls: r s =-0.330 (p < 0.001); boys: r s =-0.348 (p < 0.001)]. Conclusions: Brazilian adolescents from states with higher HDI were more active and spent more time watching TV than their counterparts from states with lower HDI.

The present study aimed to verify the contribution of different physical activity domains to “total physical activity” in Brazilian adolescents. This is a cross-sectional study using secondary data from the third edition of the National School Health Survey - PeNSE, 2015. The sample consisted of 100,497 adolescents of both sexes enrolled in the 9th grade of elementary schools. A linear regression model was used to verify how much each domain contributed to total physical activity, considering gender, type of municipality and region. The domain with the largest contribution to “total physical activity” regardless of sociodemographic and environmental variables was “extra-school physical activity” (R2 = 0.60), followed by “active commuting” (R2 = 0.34), and finally “Physical Education classes” (R2 = 0.23). The contribution of the different domains varied by gender, type of municipality and region, and it was concluded that “extra-school physical activity” make the greatest contribution to “total physical activity”, followed by “active commuting” and “Physical Education classes”. In addition, variation was observed in the contribution of domains by gender, type of municipality and region.

Insomnia is defined as persistent difficulty in falling asleep and staying asleep, despite adequate sleep opportunities, 1 and is considered to be the most common sleep disorder during adolescence, with an estimated prevalence ranging from 6% to 30% in this age group. 1 Previous research has shown that insomnia is associated with symptoms of depression, substance abuse, poor school performance, mood disorders, 2,3 social withdrawal and loneliness, 4 lower emotional regulation, 5,6 anxiety and suicidal thoughts. 7 Despite the recommendations that adolescents should sleep for 8 to 10 hours per day, 8 few young people achieve sufficient amounts of sleep, 9 which converges on a secular trend of reduced sleep duration among children and adolescents. 10 This scenario highlights insomnia as an important public health issue, as well as demonstrating the need to establish effective and suitable ways to address this problem during adolescence.In this regard, the scientific literature provides arguments for different strategies for treating insomnia, such as cognitive-behavioral therapy and pharmacotherapy. 11,12 However, although similar efficacy has been demonstrated between these therapies for treating insomnia, 13 both of them are difficult to apply on a large scale, especially in the context of developing countries. 14 Thus, studies have pointed towards physical activity (PA) as a possible low-cost strategy for reducing the effects of insomnia among adolescents. 15 In a meta-analysis on 12 studies that investigated the relationship between PA and sleep among adolescents, it was concluded that individuals with higher PA levels, assessed subjectively and objectively, were more likely to present better sleep quality. 16 Furthermore, the results from a clinical review demonstrated that moderate aerobic exercise training could be prescribed as pertinent non-pharmacological treatment for sleep