Physical education (PE) classes provide a unique opportunity for a practice of regular physical activity (PA) to a significant parcel of the population that isn’t sufficiently active. The curriculum of this discipline aims, among other goals, the development of cardiovascular capacity and there is an international calling to raise physical activity levels during these classes. However, there aren’t regular objective assessments that allow determining the level of achievement of those goals. Thus, the aim of this study was to characterize cardiovascular strain during PE classes and its variation according to the level of education, gender and type of exercises. Method: 159 heart rate (HR) recordings of 24 male and 24 female Portuguese students of the basic level of education were assessed during 3 weeks. We observed that students spent only 32.1% of classes’ time in moderate-to-vigorous activity (MVPA). Students of first level of education spend less time in MVPA (p<.01). Boys presented a higher percentage of time in VPA than girls (p=.02). In small-sided games students showed a higher relative percentage of classes’ time in VPA compared to analytical exercises (p=.003). Given the cardiovascular strain presented in this study, PE classes have only a small contribution towards the international recommendations of weekly MVPA for children (420 minutes). Article visualizations
