This study aimed to evaluate the intensity and duration of activities in Physical Education classes and to test their association with cardiorespiratory fitness. It is a cross-sectional study with 614 schoolchildren (51% girls), aged 10 to 17 years old, evaluated by accelerometers in 100 Physical Education classes in Pinhais, Southern Brazil. The intensity of the activities was determined by accelerometry (Actigraph, model WGT3X). The time spent in each intensity (sedentary, light, moderate, intense and very intense) was evaluated. Cardiorespiratory fitness was determined by the Léger test 20 meters. The average duration of the classes was 31.5 minutes (SD = 4.3). On average, boys and girls passed 23.8% and 16.9% (p <0.05) of a class in activities of moderate and vigorous intensity, respectively. The correlation between time in physical activity and cardiorespiratory fitness was significant in boys (Light, moderate and vigorous, respectively: r = 0.12, p = 0.04, r = 0.12, p = 0.04, r = 0.15, p = 0.009). In conclusion, the low correlation between physical activity time in Physical Education classes and cardiorespiratory fitness reinforces the discussion about how this subject can contribute to the public health in young population.

Resumo Fundamento: A hipertensão arterial é um grave problema de saúde pública e, nos últimos anos, tem aumentado consideravelmente em jovens. A identificação de fatores associados com essa condição é importante para guiar estratégias de intervenção nessa população. Objetivo: Determinar a prevalência e os fatores associados com a pressão arterial alterada em adolescentes. Métodos: Foi selecionada amostra probabilística de 1.242 adolescentes da rede pública de ensino de Curitiba (PR). Por meio de questionários, foram obtidos o histórico familiar de hipertensão, o gasto energético diário, informações sobre tabagismo, o consumo diário de gorduras e a classificação econômica. A circunferência da cintura foi medida por procedimentos padronizados. A pressão arterial foi aferida com manguitos adequados em 2 dias consecutivos para a confirmação da pressão arterial alterada. Frequências relativas e intervalos de confiança (IC95%) indicaram a prevalência de pressão arterial alterada. Regressões logística bivariadas e multivariadas testaram a associação dos fatores de risco com a pressão arterial alterada. Resultados: A prevalência de pressão arterial alterada foi de 18,2% (IC95% 15,2-21,6). Mais chances de pressão arterial alterada foram encontradas nos indivíduos que possuíam ambos os pais com hipertensão arterial [odds ratio (OR), 2,22; IC95% 1,28-3,85] e naqueles com a circunferência da cintura aumentada (OR, 2,1; IC95% 1,34-3,28). Conclusão: O histórico familiar positivo de hipertensão arterial e a circunferência da cintura aumentada estiveram associados a pressão arterial alterada em adolescentes. Esses fatores são importantes para guiar intervenções futuras nessa população.

Abstract Background: Arterial hypertension is a major public health problem and has increased considerably in young individuals in past years. Thus, identifying factors associated with this condition is important to guide intervention strategies in this population. Objective: To determine high blood pressure prevalence and its associated factors in adolescents. Methods: A random sample of 1,242 students enrolled in public schools of the city of Curitiba (PR) was selected. Self-administered questionnaires provided family history of hypertension, daily energy expenditure, smoking habit, daily fat intake, and socioeconomic status. Waist circumference was measured following standardized procedures, and blood pressure was measured with appropriate cuffs in 2 consecutive days to confirm high blood pressure. Relative frequency and confidence interval (95%CI) indicated high blood pressure prevalence. Bivariate and multivariate analyses assessed the association of risk factors with high blood pressure. Results: The high blood pressure prevalence was 18.2% (95%CI 15.2-21.6). Individuals whose both parents had hypertension [odds ratio (OR), 2.22; 95%CI 1.28-3.85] and those with high waist circumference (OR, 2.1; 95%CI 1.34-3.28) had higher chances to develop high blood pressure. Conclusion: Positive family history of hypertension and high waist circumference were associated with high blood pressure in adolescents. These factors are important to guide future interventions in this population.