According to Science Daily, men are more efficient than women at sweating and thus sweat more during physical exertion. A study conducted by Japanese scientists at Osaka International University and Kobe University have shown that women require higher intensities of exercise and higher temperatures overall in order to match the perspiration capabilities of men. Testosterone is believed to play a role.
Science Daily, citing the Japanese study, asserts that the reason men sweat more than women may be due to an evolutionary change. As women have less fluid in their bodies compared to men, they dehydrate more easily. Being less prone to sweating, even during physical activities and higher environmental temperatures, preserves the fluids in the body of a woman.