When people exercise, their bodies sweat and their clothes get wet. And that means their clothes, like their bodies, can smell. This is especially true if they are wearing synthetic clothesones made of material not found in nature. These materials, like polyester, are designed to be lightweight, to move sweat away from a person’s body, and to dry quickly. But these clothes can keep that bad smell a body makes when it sweats. What causes the smell? Bacteria. For years, manufacturers have been making exercise and travel clothes with different kinds of anti-odor technology. Some add chemicals or put small holes in the garments to allow the sweat and smell to escape. Others use threads or small pieces of silver in the fabric. The goal is to make clothes that one can wear longer without having to wash them. That might not sound very pleasant. But it helps people who are carrying all their supplies for camping in the wilderness.