Potential benefits of immersion in nature: stress, sleep quality, and cortisol levels in health workers

Introduction: This pilot study was conducted as part of the project "Effects of Nature Immersion Therapy 'Vitamin N' on Stress Levels in Healthcare Workers in Bogotá: An Intervention Evaluation Study, 2022-2024." Objective: To evaluate the benefits of nature immersion in an active working population, with the aim of reduce perceived stress and anxiety, improve sleep quality, and regulate cortisol levels in saliva. Methodology: A longitudinal study was conducted using a non-probabilistic consecutive sampling method. The intervention took place once a week for one hour per session over the course of a month. Measurements were taken before and after the nature immersion, and participants were divided into three groups (control, parks, and forests). Psychological scales were used to assess perceived stress (PSS-14), subjective fatigue (Yoshitake), anxiety (STAI), and sleep quality (Pittsburgh). Additionally, saliva cortisol levels were measured in a subsample. Differences in mean scores between groups were estimated. Results: The intervention groups in forests and parks showed an average reduction of 2.6 points on the PSS-14 scale, while the control group showed a reduction of only 0.4 points. A decrease in general fatigue was observed in the parks group, but there were no significant changes in physical or mental fatigue. STAI levels did not change in any of the groups after the intervention. Although the intervention groups showed a slight improvement in sleep quality, it remained moderate and not statistically significant. Finally, a reduction in cortisol levels was observed in the intervention groups after the therapy. Conclusions: The results suggest that nature immersion therapy may have beneficial effects in reducing stress and fatigue, as well as in improving sleep quality and regulating cortisol levels in actively working individuals.