We reviewed the literature concerning the maximal sweating rate (SRmax) during heat acclimatization, walking in desert heat and marathon running, and analyzed it from the viewpoint of sex, age, level of maximal oxygen uptake, and experimental conditions, i.e., ambient temperature, relative humidity, work intensity, work type, working duration, seasonal factors and the techniques of heat acclimatization. Exercise simulation, walking, running or bicycling, to induce the SRmax was conducted in a hot climatic chamber or in the desert. The SRmaxs due to marathon running were 1,000 to 1,200 g.h-1 in the cold season and 1,500 to 2,000 g.h-1 in the hot season. After several days of heat acclimatization, sweating capacity in the exercise simulation reached a maximum rate, over 2,000 g.h-1. There was a sexual difference in the SRmax, and the sweating capacity in the female was less than that in the male. Thus, the maximal sweating capacity in human was observed by prolonged moderate muscular exercise under thermal stress and internal and/or external heat loads.