Catalán, AnaTognin, StefaniaHammoud, RyanAymerich, ClaudiaPedruzo, BorjaBilbao González, AmaiaSalazar de Pablo, GonzaloPacho, MaleinFusar Poli, PaoloGonzález Torres, Miguel Ángel2025-06-052025-06-052023-11Catalan, A., Tognin, S., Hammoud, R., Aymerich, C., Pedruzo, B., Bilbao-Gonzalez, A., Salazar de Pablo, G., Pacho, M., Fusar-Poli, P., & Gonzalez-Torres, M. Á. (2023). Understanding the relationship between time spent outdoors, mental well-being and health-related behaviours in a Spanish sample: a real time smartphone-based study. Psychiatry Research, 329. https://doi.org/10.1016/J.PSYCHRES.2023.1154940165-178110.1016/J.PSYCHRES.2023.115494http://hdl.handle.net/20.500.14454/2948Introduction: COVID-19 pandemic has affected our lifestyle and physical and mental well-being. We aimed to study the effect of being outdoors and mental well-being after the COVID-19 pandemic. Material and methods: We used smartphone based ecological momentary assessments (EMA) (Urban Mind app) to study the mental well-being of the Spanish general population. We collected socio-demographic data, past and current physical and mental health, and social and physical environment. Participants were recruited during 5 months (February to June 2021). Longitudinal associations between EMA and anxiety, depression, loneliness, tiredness, and happiness during the assessments were investigated using random intercept ordinal logistic regression models. Results: 274 subjects downloaded the app and completed the baseline assessment. 66 participants completed at least 50 % of the assessments. Being outdoors was related to a lower likelihood of anxiety (OR: 0.48, 95 %CI 0.34–0.66), depression (OR: 0.40, 95 %CI 0.28–0.56), tiredness (OR: 0.47, 95 %CI 0.35–0.63), and loneliness (OR: 0.59, 95 %CI 0.42–0.84), and a higher likelihood of happiness (OR: 2.14, 95 %CI 1.57–2.93). Conclusions: Being outdoors is related to better mental health in the general population independently of other factors (baseline mental well-being or socio-demographic characteristics). Public policies should include measurements to promote outdoor spaces in urban settings.eng© 2023 The Author(s)AnxietyCOVID-19DepressionMental well-beingOutdoorsjournal article2025-06-051872-7123