Sweat is a clear, salty liquid produced by the sweat glands in the skin. It primarily consists of water, but also contains small amounts of salts, urea, and other substances. The main purpose of sweating is to regulate body temperature; when the body heats up, sweat evaporates from the skin's surface, cooling the body down. Sweating can occur during physical activity, hot weather, or emotional stress. The process is controlled by the autonomic nervous system, which automatically triggers sweat production without conscious effort. Different people sweat at different rates, influenced by factors such as genetics, fitness level, and environment.