<![CDATA[The mood of late adolescents (ages 17-18) tends to fluctuate due to academic demands, social relationships, and the transition to the workforce or college. Physical activity is viewed as a modifiable behavioral factor that can support adolescents’ emotional well-being; however, local empirical evidence from Brebes Regency remains limited. This study aims to analyze the relationship between physical activity and mood (positive affect and negative affect) among adolescents aged 17-18 years in Brebes Regency. The research method employed a survey design with a cross-sectional approach. The population consisted of students at SMK Semesta Bumiayu, Brebes. A sample of 74 students was selected using convenience sampling. Physical activity was measured using the Indonesian version of the PAQ-A, while mood was measured using the Indonesian version of the PANAS-C. Data were analyzed using the Spearman rank correlation test (SPSS 27). Results: There was a positive and significant relationship between physical activity and positive affect (ρ = 0.661; p = 0.008) as well as a negative and significant relationship between physical activity and negative affect (ρ = –0.486; p = 0.014). Physical activity explained 43.7% of the variance in positive affect and 23.6% of the variance in negative affect. These findings support physiological (neurotransmitters, sleep quality), psychological (self-efficacy, emotion regulation), and social (peer support) mechanisms linking physical activity to mood. The association was stronger for positive affect than for negative affect, consistent with previous research. Conclusion: Higher levels of physical activity are associated with better positive mood and lower negative mood among adolescents aged 17-18 years. This study supports the strengthening of physical activity programs in schools as a strategy to promote adolescents’ psychological well-being.]]>
