If you listen to commercials, you should never let anyone see you sweat. However, that sweat is very important. "During heavy exercise, your muscles generate enough heat to boil several cups of coffee," Dr. Oz says. Without sweating, "heat would literally cook your internal organs and kill you."
Just below your skin are 3 million sweat glands, each a coiled tube four feet long loaded with liquid. As your body heats up the tubes contract and squeeze a droplet of sweat out onto your skin. As the sweat evaporates, it draws heat away from your body, cooling you.
And, as a special bonus feature, sweat can influence and attract people around you. "The apocrine glands—they're the ones in your armpits and in your genital areas—they actually release chemicals that signal to each other like animals: pheromones. You will instinctively like somebody or not based on their smell," Dr. Oz says.