By Dr. Gabe Mirkin
Yes. A study from Japans shows that women need to work much harder than men to start sweating during exercise. (Experimental Physiology, October 2010). You start to sweat when your body heat reaches a certain temperature. Men start to sweat earlier than women do because they start to sweat at lower temperatures.
You sweat to cool your body. Most women have less body fluid than men, so they become dehydrated more easily, and dehydration can kill. Sweating later and at higher temperatures is an evolutionary adaptation for women to lose less fluid so they can survive fluid loss in hot weather.
Sweating lowers body temperature. Almost 80 percent of the energy you use to power your muscles during exercise is lost as heat. The harder you exercise, the more heat you generate. Increasing body temperature increases your muscles’ requirements for oxygen, so the higher your body temperature, the more oxygen your muscles need to move your body. Anything that increases need for oxygen weakens you and slows you down. Men usually have larger muscles. Starting to sweat at lower body temperatures prevents a rise in body temperature so they can move faster and with more strength.
Out-of-shape people start to sweat later than fit people do. As you become more fit, you sweat earlier in your exercise, at lower temperatures, and lose more fluid through sweating. The untrained women in this study had the most delayed sweating response, required higher body temperatures to start sweating, and did not sweat as much.