Psychological benefits of green exercise in wild or urban greenspaces: A meta-analysis of controlled trials

Green exercise, the combination of exercise and nature exposure, is known to benefit physical and mental health. However, there is a lack of quantitative evidence to support the psychological advantage of green exercise over non-green exercise. Also, it is unclear if there are psychological differences between green exercise in wild environments and urban greenspaces. Therefore, we conducted a systematic literature search for outcomes concerning measures including the Profile of Mood States (POMS), Spielberger State-Trait Anxiety Inventory (STAI), Semantic Differential Method (SDM), Positive and Negative Affect Schedule (PANAS), and Restorative Outcome Scale (ROS). Nineteen studies with 1662 participants were included in a meta-analysis to examine the advantages of green exercise and compare them in the two types of natural environments. The results indicate that green exercise may lower negative affect, including anxiety, tension, anger, depression, and fatigue. Meanwhile, green exercise may lead to higher positive moods and emotions, including vigor, comfort, natural feeling, and relaxation. Nevertheless, the effect on overall positive affect was not statistically significant. The comparative results suggest that wild environments may be more effective than urban greenspaces in improving vigor and comfort during green exercise. In conclusion, our findings support the advantages of green exercise over non-green exercise, meanwhile implying potential psychological differences between exercises in wild environments and urban greenspaces. Due to the limited number of studies and high heterogeneities, a future review is warranted to re-examine the psychological benefits.