Background/Objectives: Despite global efforts to promote moderate-to-vigorous physical activity (MVPA) among youth, limited evidence exists regarding adolescents’ knowledge of official physical activity (PA) guidelines. The aim of this study was to assess adolescents’ knowledge of MVPA guidelines and examine its potential association with meeting PA recommendations and levels of sedentary behavior. Methods: This cross-sectional study was conducted in 2025 with a sample of 1032 adolescents (50.5% boys) from northernmost Brazil. Data were collected using a self-administered questionnaire and included information on knowledge of PA guidelines, PA levels, sedentary behavior duration, and sociodemographic characteristics. Associations were tested using logistic regression models. Results: Only 11.7% of adolescents accurately identified all components of the PA recommendations. Boys who met PA guidelines were 15.76 times more likely to be aware of the official recommendations (95% CI: 7.14–24.48), while girls had 10.05 times higher odds (95% CI: 4.43–16.67). Adolescents who were less sedentary (<3 h/day) were significantly more likely to know the guidelines, both among boys (OR = 2.00; 95% CI: 1.08–3.70) and girls (OR = 3.13; 95% CI: 1.12–8.33). Conclusions: The low level of awareness regarding official PA guidelines among adolescents is concerning, particularly given the strong association between such knowledge and the adoption of more active and less sedentary behaviors. Public health and educational strategies should prioritize health literacy in school curricula and community-based programs to promote more active lifestyles and reduce sedentary behavior among youth. Future studies should use longitudinal designs to clarify causal links and test practical interventions.
Pinto et al. (Tue,) studied this question.