It turns out that there actually are differences in the way men and women sweat. According to Yoshimitsu Inoue and his team from Osaka International University, men really do sweat more than women.
The researchers compared roughly equal numbers of physically trained and untrained men and women. Each volunteer was asked to ride an exercise bicycle for an hour. For both men and women, physically fit individuals sweated more than their untrained cohorts. However, men sweated more than women in both the trained and untrained groups, and men showed a greater increase in sweating with physical training.The authors speculate that the difference in the sexes may have to do with the lower total fluid volume of women. A less efficient cooling system may have been an evolutionary trade-off for staving off dehydration. In any case, this finding has implications for both female athletes and for women in extremely hot environments.