Comparing psychological and physiological responses to exercise in natural outdoor, urban outdoor and indoor environments

Introduction. Exercising in natural environments (i.e., green exercise) has been suggested to provide greater physiological and psychological health benefits compared to urban or indoor environments (Gladwell et al., 2012). This study evaluated the psychological and physiological restorative effects of a 1-hour light-to-moderate intensity exercise session. Methods. In a randomized crossover design, 15 healthy male subjects (age: 28±5 years) performed a 1-hour walk at a controlled pace (6 km/h) in three different environments: green natural (forest park, G), built outdoor (urban, U) and built indoor (laboratory, I). Questionnaires for psychological assessment were administered to investigate the feeling of restoration, the emotional states, and the enjoyment of physical activity. Physiological indices, including Heart Rate Variability (HRV), Salivary Cortisol and Blood Pressure (BP), were assessed before and after the intervention. Results. A series of repeated-measures ANOVA indicated a statistically significant effect of the environment. Participants reported higher levels of relaxation, lower levels of anxiety, increased feelings of restoration, and greater enjoyment following exercise in the G environment compared to other settings. Halfway through the walk, participants reported a significantly lower perceived effort in G compared to I (mean decrease 0.87±0.20). Systolic BP and salivary cortisol were significantly reduced after the exercise interventions. G was significantly associated with a lower salivary cortisol concentration compared to U and I. A significant effect of the environment was found on HRV indices, which were higher in the post-exercise period in G compared to I. Conclusions. These results indicated that one hour of light-to-moderate intensity exercise conducted in a natural green environment elicited positive physiological and psychological stress-related responses. The study also highlighted the higher restorative power of a green natural environment. Natural environments may promote exercise adherence and increase physical activity levels, supporting a healthy lifestyle.