The Evolution of Sweating: A Week in the Heat

Ever wondered how our bodies adapt to heat? A recent study explored this by tracking the changes in the amount of skin covered in sweat over seven days of heat acclimation. Nine adults, with both men and women, were put through a heat test every two days. They cycled for two hours in a hot, humid room. The heat and humidity were gradually increased until their bodies couldn't handle it anymore, which was when they started to sweat more. Between these tests, they also cycled for an hour and a half to get used to the heat. The study found that the amount of skin covered in sweat (ωmax ) increased over the seven days. On the first day, only about 68% of their skin was covered in sweat, but by the seventh day, it was up to 87%. The whole-body sweat rate and the number of active sweat glands also increased, especially on the fifth and seventh days. The amount of sweat each gland produced didn't change much. So, the body adapts to heat by increasing the number of active sweat glands, not the amount of sweat each gland produces.