Int. J. Environment and Health, Vol. x, No. x, xxxx 1 Copyright © 200x Inderscience Enterprises Ltd. Interactions between physical activity and the environment to improve adolescent self-esteem: a randomised controlled trial C. Wood*, G. Sandercock and J. Barton School of Biological Sciences, University of Essex, Colchester, CO4 3SQ, UK E-mail: cjwood@essex.ac.uk E-mail: gavins@essex.ac.uk E-mail: jobarton@essex.ac.uk *Corresponding author Abstract: Natural environments promote physical activity (PA) and are psychologically restorative. In adults, performing PA in nature provides additive benefits for self-esteem (SE). Studies in adolescents indicate no such effect. However, they have not examined the effect of interaction with natural environments. The aim of this study was to analyse the effects of exercising in natural and built environments on adolescent PA and SE. Sixty adolescents participated in a natural and built orienteering course in a randomised order. PA was assessed throughout whilst SE was assessed pre- and post-intervention. There was a significant effect for PA due to environment (P < 0.001) and sex (P < 0.01). Almost half the time in the natural environment was spent in moderate to vigorous PA, compared to a quarter in the built. The PA significantly improved SE (P < 0.05); however there was no environmental effect (P > 0.05). Natural environments should be used as a tool for engaging adolescents in PA. Keywords: interactions; physical activity; environment; self-esteem; randomised controlled trial; green exercise; natural; built; orienteering; adolescents; health. Reference to this paper should be made as follows: Wood, C., Sandercock, G. and Barton, J. (xxxx) ‘Interactions between physical activity and the environment to improve adolescent self-esteem: a randomised controlled trial’, Int. J. Environment and Health, Vol. x, No. x, pp.xxx–xxx. Biographical notes: Carly Wood is a Lecturer and Research Officer in the Centre for Sport and Exercise Science at the University of Essex and is part of the ‘Green Exercise’ research team. Her research focuses on the effects of Green Exercise in children and young people and the use of Green Exercise as a therapeutic intervention for vulnerable groups such as youth at-risk. She is interested in whether natural environments can facilitate physical activity in these populations and also whether taking part in Green Exercise provides benefits for psychological well-being, as has been demonstrated in adults. Gavin Sandercock is a Senior Lecturer in the Centre for Sport and Exercise Science at the University of Essex and course director of the MSc Cardiac Rehabilitation. His research interests include geographical and social interactions with exercise, paediatric physical activity and fitness and prevention and rehabilitation of cardiovascular disease. He is the principal