87 / 2025-03-31 15:17:32

Improving thermal comfort and cognitive ability of manual workers by cooling garment based on brain function networks analysis

cooling garment, brain function networks, thermal comfort, cognitive performance

Nowadays, hot waves happened more often in summer due to the global climate change, which leads to hot indoor environment when air conditioning systems are absent, which can be more intolerable for manual workers taking higher activity levels. This study investigates the effects of cooling garments (CG) on thermal comfort, cognitive performance, and brain function networks indices of subjects under a hot condition of 33 °C. 20 subjects were asked to conduct packing activities with metabolic rate of 2.7 met in two conditions (with work garments, WG, with PCCG of 17 °C). Subjective votes (thermal sensation, thermal comfort) were collected. EEG signals and heart rate was measured. Four cognitive tests were performed including letter search test, Stroop test, picture recognition test, and number remember test. Compared to the WG condition, the CG condition significantly reduced the participants' thermal sensation and improved thermal comfort. In terms of heart rate variability, the CG significantly enhanced parasympathetic activity, promoting autonomic nervous system regulation. RMSSD and SDNN were significantly increased compared to the WG condition, while the LF/HF ratio significantly decreased. Participants' cognitive performance was also significantly improved. The CG also effectively improved the connectivity of brain networks, enhancing information exchange between brain regions. Under the CG condition, the clustering coefficient and global efficiency were significantly increased, while the characteristic path length was significantly reduced. The clustering coefficient was positively correlated with the picture recognition test results; global efficiency was positively correlated with the letter search and Stroop test results; and characteristic path length was negatively correlated with the letter search and picture recognition test results. The results indicate that the brain function networks can be used to evaluate thermal comfort and cognitive ability of manual workers during the use of CG.