Dose-Response Relationship between Green Walking Distance and Restorativeness of Pedestrians: Insights from a Pilot Study with Micro-Climate Measurements

Walking is a crucial transportation choice and physical activity for urban residents, especially with increasing urbanization and environmental issues. While it is well-established that walking through green spaces offers significant health benefits, the dose-response relationship between green walking exposure and its psychological impacts remains unclear. Additionally, the influence of the thermal environment on these benefits requires further investigation.

A protest-posttest and crossover experiment conducted in a campus green space during a subtropical transitional season. A total of 37 participants were randomly assigned to two walking interventions, each 2 km in length, within the same space. The interventions were separated by a one-week washout period, and the walking directions (clockwise or counterclockwise) were also randomized.

The Perceived Restorativeness Scale and Positive and Negative Affect Scale were used before and after a stress test, at the midpoint of and after the walk. Simultaneously, skin temperature and skin conductance levels were continuously recorded during the trial. Physical environmental parameters during the walks were measured using a mobile weather station carried by a researcher accompanying the participants. These parameters included air temperature, relative humidity, long-wave and short-wave radiation, noise levels, and major air pollutants such as CO and PM_2.5.

Physiological Equivalent Temperature during the walks was calculated, and paired t-tests and correlation analysis  were used in Statistical analysis. The results showed that green walking had significant effects on participants’ physiological and psychological indicators, with noticeable stress reduction and mood improvement. Among the distances tested, a 2 km walk yielded the best restorative benefits, whereas the health benefits were weaker at 1 km and 2.5 km. Additionally, thermal comfort during the walks mediated the relationship between walking and the physiological, psychological, and restorative benefits. The mental health of pedestrians after green walking could be partially offset by thermal stress.