RESUMEN
Using endurance training in nature as a resource in inpatient psychotherapy Objectives: Although positive effects of nature on mental health are generally well-documented, clinical studies into the deliberate use of nature as a resource in in-patient psychotherapy are missing. The following study examined whether an endurance training intervention in psychosomatic rehabilitation showed differential effects on patients depending on its implementation in an indoor or outdoor nature setting. Methods: Endurance training indoors (ergometer) was compared to training outdoors in the nature (walking) in N = 88 in-patients of a psychosomatic rehabilitation clinic using a linear mixed effects model. Health effects were examined using a standardized questionnaire on somatic symptoms (Giessener Beschwerdebogen GBB-24) and a mood questionnaire (Aktuelle Stimmungsskala ASTS). Seasonal effects were assessed by testing half of the sample in summer and half in winter. Secondary analyses of the linear mixed effects model were run for depression as primary diagnosis which accounted for half of the sample. Results: A nature setting positively predicted improvements on the ASTS positive mood scale (B = 0.34; t(245) = 3.25; p = .001; pBonferroni = .052). No significant interaction was found between the effect of the training setting and depression as primary diagnosis (B = -0.05; t(245) = -0.30; p = .76) in secondary analyses. Conclusions: The results primarily point to an improvement in mood following endurance training in a nature setting. Improvements are independent of depression as the primary diagnosis.