Effects of a forest therapy camp on cancer survivors’ stress, mood and natural killer cells in Korea

Purpose: This study investigated changes in psychological and physiological indices in cancer survivors who participated in a forest therapy camp in Korea.Methods: A total of 37 cancer survivors (19 and 18 in the experimental and control groups, respectively) participated in this study. Over a 2-night and 3-day period, the participants in the experimental group took part in a forest therapy camp that included activities such as gymnastics, walking, five-senses experiences, and meditation. Both groups completed self-report questionnaires that measured their stress levels and profile of mood states, both before and after the forest therapy camp. Blood samples were collected to measure the levels of cortisol, serotonin, and natural killer (NK) cells.Results: After the forest therapy camp, the experimental group exhibited reduced stress levels (p = .031) and a significant improvement in total mood disturbance (p = .047) when compared with the control group. The level of serotonin also significantly increased (p < .001). However, in contrast to the prediction, a significant increase in cortisol was noted in the experimental group relative to the control group (p = .016). Moreover, no significant difference in NK cells was noted between the two groups.Conclusion: Forest therapy can be easily applied to cancer survivors. The positive psychological effects of the forest therapy camp were confirmed by improvements in stress and mood states and the increased level of serotonin in forest therapy camp participants. However, there is a need for a follow-up evaluation of cortisol and NK cells due to the absence of significant between-group differences.