The improving effect of airflow on thermal comfort in moderately hot environment: a comparative study based on...

In China, gyms and fitness centers commonly encounter elevated indoor temperatures during the summer months, which not only adversely affects users' training experience but may also exacerbate associated health risks. Moreover, as these facilities frequently accommodate individuals with diverse exercise backgrounds, notable differences in thermal perception often emerge among them under the same thermal conditions. This study recruited twelve sport college students (SC) and twelve ordinary college students (OC) to represent groups with different exercise backgrounds. Under moderately hot environmental conditions, participants performed exercise activities at moderate, high, and very high intensity levels under both no fan and fan conditions, to investigate the differential effects of airflow on thermal responses across groups. Furthermore, body compositions were measured to explore the underlying mechanisms for differences in thermal sensation between individuals with varying exercise backgrounds. The results indicated that individuals with an exercise background exhibited better thermal adaptation in moderately hot environments. Under the no fan condition, the thermal sensation vote (TSV) of the SC group was 17% to 53% lower than that of the OC group, while their thermal comfort vote (TCV) was 10% to 16% lower. Under the fan condition, the TSV and TCV values decreased by 40%-72% and 50%-80% for the SC and OC groups, respectively. The preferred air speed increased with exercise intensity, but no significant differences were observed between the two groups. During exercise, the preferred air speed was approximately 2.8 m/s for the SC group and 2.7 m/s for the OC group. Body composition is a key reason for the differences in thermal perception between groups with different exercise backgrounds.