Effect of a forest therapy program and the forest environment on female workers' stress

This study aims to determine the effects of forest therapy (FT) program and the frequent use of forest environment in daily life on workers' stress levels on the hypothesis that FT program and frequent use of forest environment in daily life would reduce workers' stress level both psychologically and physiologically. Participants were workers in the healthcare and counseling service industries, which are known for their heavy emotional burden on workers, and thereby had high levels of employee stress and burnout. In total, 211 subjects were recruited and divided into two groups using a screening survey according to the frequency of using the forest environment in daily life. Of the 91 subjects who reported low frequency of use, 19 female workers volunteered to join the FT program and were assigned to the experimental group. Among the 120 subjects with a high frequency of use, 20 female workers volunteered for the assessment of stress levels and were subsequently assigned to the control group. We measured stress levels through heart rate variability, cortisol concentration, natural killer cell activity, and scores on the Maslach Burnout Inventory-General Survey, Worker's Stress Response Inventory, and the Recovery Experience Questionnaire. The results showed subjective stress relief after the FT program. The experimental group exhibited higher scores on the mastery factor of the Recovery Experience Questionnaire. Further, the experimental group showed more recovery experiences following participation in the FT program. The control group showed a significantly higher standard deviation in normal-to-normal intervals and the square root of the mean squared differences of successive NN intervals (measures of heart rate variability) and lower cortisol level as compared to the experimental group. These results suggest that frequent users of the forest environment are less stressed than are low frequency users, and that the FT program relieves participants' psychosocial stress. (C) 2015 Elsevier GmbH. All rights reserved.