Our study aimed to evaluate how psychological mood states as well as blood pressure, pulse rate, and the levels of salivary stress biomarkers change between before and after forest or urban walking. In 2016-2018, 33 young people participated in both forest and urban walking, for two hours each. Salivary amylase, blood pressure, and pulse rate were measured before and the next day after walking. Psychological mood states of the participants were also checked using a short form of the Profile of Mood States questionnaire. As the results, the levels of salivary amylase showed decrease in 19 participants (63%) after forest walking, and in 15 participants (45.5%) after urban
walking. However, the mean level of salivary amylase did not show significant differences between before and after walking either in forest or urban environments. On the psychological dimension of the participants, the scores of tension-anxiety (p < 0.01), depression-dejection (p < 0.01), anger-hostility (p < 0.01), fatigue (p < 0.05), and confusion (p < 0.01) significantly decreased after forest walking but not after urban walking. Our findings suggest that immersing the body in forest environment even for a short time would improve negative mood and reduce stress.
