As much as 70 percent of your body’s heat can escape through exposed hands, feet, and head. Wet clothes actually conduct heat away from the body. When the Chinese invented the toothbrush in 1490, the bristles were made of animal hairs. Nylon toothbrushes were first sold in the U.S. in 1938. Chewing gum for more than 20 minutes a day stresses your jawbone, gums, and the biting surfaces of your teeth. However, chewing a stick of sugarless gum for a few minutes stimulates your saliva secretion and helps to clean your teeth. Brushing distributes protective and moisturizing natural oils along the whole length of the hair shaft. It also stimulates your scalp and removes loose scales. Poor posture can cause rounded shoulders, backaches, and swayback. It also may keep your internal organs from working properly.