Effect of temperature and clothing thermal resistance on human sweat at low activity levels

Human sweat is an important factor in calculating body evaporative heat loss. Most studies in this topic focus on extremely high metabolic rates. Therefore, this study performs a quantitative experimental research for human skin temperature and sweat at low activity levels. The experimental results indicate that 15 min is enough to stabilize metabolic rate and skin temperature at low activity levels. Moreover, gender has an important effect on metabolic rate, and the greater the metabolic rate, the greater the difference. Human sweat was positively correlated with metabolic rate, ambient temperature, and clothing thermal resistance. However, the rate change was not static. Change in sweat rate according to one of above three parameters was affected by the other two parameters. Influence of ambient temperature was the greatest, followed by metabolic rate and clothing thermal resistance, respectively. Three commonly used models for predicting human sweat were analyzed and compared. Coefficients of the two models with higher prediction accuracy were revised. •Experiments on effect of temperature and clothing thermal resistance on sweat at low metabolic rate were conducted.•Sweat is significantly influenced by metabolic rate, temperature and clothing thermal resistance.•Sweat change rate according to one of above three parameters was affected by other two.•Influence of temperature was the greatest, followed by metabolic rate and clothing thermal resistance.•Three commonly used models for predicting sweat were compared and revised.