Forest bathing (Shinrin-Yoku) as an integrative strategy for mental and cardiovascular health: a quasi-experimental study in Brazil

Forest bathing (Shinrin-Yoku) therapy has emerged as a promising environmental health intervention with measurable physiological and psychological benefits. Evidence from the United States, Europe, and Asia indicates that exposure to natural environments reduces stress-related biomarkers, including salivary cortisol, anxiety symptoms, and blood pressure. However, Brazilian evidence remains limited, particularly in the Cerrado biome and within the context of the public health system. To analyze the effects of forest bathing therapy, compared with guided urban exposure, on physiological and psychological markers of stress, anxiety, and depression among adults residing in the Federal District, Brazil. A quasi-experimental study was conducted with two parallel groups: an intervention group participating in eight forest bathing sessions and a control group exposed to guided urban environments over the same period. Primary outcomes included systolic and diastolic blood pressure (SBP, DBP), salivary cortisol levels, perceived stress (PSS-10), and psychological symptoms assessed by the Depression, Anxiety and Stress Scale (DASS-21). Intragroup and intergroup comparisons were performed using the Wilcoxon rank-sum test (Mann–Whitney U-test), Stuart–Maxwell test, and Fisher’s exact test, adopting a 5% significance level. Groups were comparable at baseline. No significant intergroup differences were observed for SBP or DBP; however, cortisol reduction was significantly greater in the intervention group ( p = 0.024). Within-group analyses demonstrated significant reductions in SBP (119.50 → 108.00 mmHg; p = 0.001) and salivary cortisol (0.29 → 0.16 μg/dL; p = 0.002) among participants exposed to forest bathing. Psychologically, the proportion classified as low stress increased from 17.4 to 52.2% ( p = 0.006). DASS-21 results showed significant redistribution toward the normal category for anxiety (52.2% → 95.7%; p = 0.042) and stress (26.17% → 69.6%; p = 0.018). Forest bathing produced acute reductions in physiological and psychological stress markers, supporting its role as a nature-based, complementary public health strategy. These findings highlight its potential integration into Brazil’s Unified Health System (SUS), particularly Integrative and Complementary Health Practices (ICHP), reinforcing the relevance of environmental exposures in mental health promotion.