Influence of thermal comfort of green spaces on physical activity: Empirical study in an urban park in Chongqing, China

The thermal comfort of green spaces, an important factor affecting physical activity, is the premise of outdoor physical exercise. Currently, the way in which thermal comfort influences outdoor physical activities is not fully understood. This study aimed to investigate the effect of thermal comfort in green spaces on the participants' attendance, duration, metabolic rate, and frequency of physical activity during hot summer. We used questionnaire surveys and activity records to evaluate physical activity, and numerical simulations to reproduce the thermal environment in five green spaces in an urban park in Chongqing, China. Thermal comfort was evaluated by physiological equivalent temperature (PET) and thermal sensation vote (TSV). Results showed that: 1) Attendance showed a double peak in shaded spaces, and a single peak in less shaded spaces that offered activity facilities. 2) The hourly average activity duration reached its maximum (37 min) at PET was 30.46 °C. Large areas of tree-shaded squares and pavilions, and fitness trails were more conducive to longer durations of outdoor activity. 3) PET negatively affected the hourly per capita metabolic rate (R2 = 0.9321). Metabolic rate was barely affected by the PET of older adults over the age of 65 years. 4) TSV was inversely proportional to frequency. Well-shaded spaces and spaces that provide activity facilities could increase the activity frequency. These results may serve as a reference for designing improved green spaces that can promote outdoor exercise while safeguarding health.