Sweaty feet known as palmoplantar hyperhidrosis, means excessive sweating and usually causes smelly feet. The sweat glands in the foot area of the body are what produce the odor. Because the foot has around 250,000 sweat glands, feet tend to sweat more than other parts of the body. These sweat glands have a purpose, however. The reason for all these sweat glands is to keep the skin moist, acting as a thermostat, in a sense, to help regulate the body temperature.