PMC

a, Schematic of human body temperature self-regulation mechanism. When body temperature increases, human body perspires to cool down its own temperature, which leads to reduction or suspension of perspiration in reverse. b, Schematic of the artificial sweating skin platform with feedback control loop simulating human body temperature self-regulation mechanism. c, Schematic of the detailed structure of the artificial sweating skin. The schematic in the red dash box shows the working mechanism of the modified Janus-type wicking layer which realizes uniform sweating mimicking human skin sweating scenario. d, Measurement results of skin temperature and sweating rate for bare skin, i-Cool (Cu) and commercial textiles (skin power density: 750 W/m², ambient temperature: 22 °C). Insets show the photographs of i-Cool (Cu) and cotton after one-hour stabilization during the tests. Asterisk, Statistical significance of skin temperature and sweating rate between the i-Cool (Cu) and other textiles, Welch’s t-test p < 0.001. e, Measurement results of skin temperature and sweating rate for bare skin, i-Cool (Cu) and other conventional textiles under different skin power densities. Asterisk, Statistical significance of skin temperature and sweating rate between the i-Cool (Cu) and other textiles at 750 W/m², 880 W/m² and 1035 W/m², Welch’s t-test p < 0.001. f, Measured skin temperature and sweating rate at high ambient temperature (40 °C). 750 W/m² power density was applied. Asterisk, Statistical significance of skin temperature and sweating rate between the i-Cool (Cu) and other textiles, Welch’s t-test p < 0.001. g, Measured skin temperature and sweating rate in high relative humidity ambient (~80%). Asterisk, Statistical significance of skin temperature and sweating rate between the i-Cool (Cu) and other textiles, Welch’s t-test p < 0.001. All the error bars represent standard deviation of measured data.

Frequency histograms of (a) absolute whole-body sweating rate and (b) relative whole-body sweating rate from 461 athletes (327 adults, 134 youth; 369 male, 92 female) of various sports (e.g. American Football, basketball, baseball, soccer, tennis, and endurance) tested during training or competition in various environmental conditions (15–50 °C, 20–79% relative humidity). The vertical line represents the mean value. Reproduced from Baker et al. [], with permission

Regional sweating rate vs. regional sweat [Na]. Data points represent the group (26 subjects) mean ± SEM at each regional site (DFA, dorsal forearm; VFA, ventral forearm). Regional sweating rate and sweat [Na] measured with the absorbent patch technique during cycling exercise in the heat (30°C, 42% relative humidity). Redrawn from Baker et al. 2018 [].

Whole-body sweating rate and whole-body sweat [Na] and [Cl] comparison between low (45% maximal oxygen uptake) and moderate (65% maximal oxygen uptake) intensity cycling exercise in a warm (30°C and 44% relative humidity) environment (n = 11 men and women). Solid circles show individual data. Open circles show mean data (p < 0.05 between low and moderate intensity for sweating rate, sweat [Na] and sweat [Cl]). Redrawn from Baker et al. 2019 [].