The purpose of this study is to explore physiological and psychological changes immediately after a short-term visit to urban parks in an uncontrolled condition. Sixty park visitors completed a short questionnaire evaluating their subjective well-being (SWB) and donated a saliva sample immediately before and after their park visit. In addition, participants wore a pedometer to track their physical activity level during the park visit. Results indicated the levels of all biomarkers (cortisol, dehydroepiandrosterone [DHEA], and cortisol/DHEA ratio) decreased while SWB scores increased after the park visit. The duration of park visit was identified as a key variable significantly associated with cortisol reduction, and changes in SWB scores after the park visit were significantly associated with changes in cortisol level. A park visit duration of 21.8 min has the predictive ability to discriminate park visitors who exhibit reductions in cortisol levels after the park visit from those who do not.
