This experimental study investigated differences in perceived restorativeness, mood, attention capacity and physiological reactions when visiting city and forest environments. Twenty female patients diagnosed with exhaustion disorder visited three different forest environments and one city environment in randomized order. They performed a standardized 90-min test procedure in each of these environments. Evaluation of the environments and psychological effects in mood were studied with self-administered questionnaires. Attention capacity was studied with Necker Cube Pattern Control task. Physiological responses were measured with regularly scheduled controls of heart rate and blood pressure, and a single test of heart rate recovery. Visits to the forest environments were perceived as significantly more restorative, enhancing mood and attention capacity compared to the city. This also applies to the results of heart rate and to some extent to the results of the diastolic blood pressure. The results from this experimental study support our hypothesis that short visits to forest environments enhance both psychological and physiological recovery and that visits to forest environments are likely to be beneficial when suffering from exhaustion disorder. 

It has been suggested that humans suffering from mental exhaustion recover better in environments that do not demand directed attention. Hence, we hypothesized that forests have restorative effects and examined whether the boreal forest in northern Sweden can be used for rehabilitation from stress-related exhaustion in a pilot study. Six participants suffering from stress-related exhaustion were offered visits twice a week, for 11 weeks, in six different forest settings: pine forest, mixed forest, spruce forest, forest by the lake, the forest with a small stream and rock outcrops. The participants chose one forest setting prior to each visit, and the mental state of each participant was evaluated before and after each visit. Interviews focusing on the experience of the forest were conducted after the 22 visits. Solitude and forest settings with light were identified as positive factors for recovery. Despite the limited amount of data, the results showed that the forest visits had significant positive effects on the participants' mental state. The interviews also indicated that the concept is suitable for use in larger randomized studies and that it is important to provide various forest settings to meet individual preferences of the participants and to offer the possibility of solitude.

Modern society is faced with increasing incidence of mental and behavioural disorders. The objective of this study was to evaluate whether visits to boreal forests can be utilised for rehabilitation from exhaustion disorder (ED). This randomised controlled trial comprised of a forest rehabilitation group (n = 35) and a waiting list group (control group) (n = 43) with subsequent cognitive behavioural rehabilitation (CBR) for all participants in both groups. The recovery from ED was compared between the forest rehabilitation and the control group at baseline, after the forest rehabilitation (3 months), and at the end of the CBR (1 year). Both groups had enhanced recovery from ED after the 3-month intervention period and at the end of the CBR (1 year), and there were no significant differences between the groups in terms of psychological health measures. Mental state, attention capacity and preferences for different forest environments were studied during the forest visits. Mental state was improved, but it showed some seasonal differences. A significant effect on attention capacity was found for single forest visits, but there was no effect found for the rehabilitation period as a whole. The most popular forest environments contained easily accessible, open and bright settings with visible water and/or shelter. Forest rehabilitation did not enhance the recovery from ED compared to the control group, but the participants’ well-being was improved after single forest visits.