Keeping warm in Antarctica is not simply a matter of piling on more clothes. In fact, overdressing can be as hazardous as underdressing. If you get too hot, you sweat, which can lead to freezing, because moist skin transmits heat almost 20 times faster than dry skin. Similarly, if your clothes get wet, your skin can lose as much heat as if it had no covering at all. The best way to keep properly insulated is to wear clothes that repel wind but allow both body moisture to escape and air spaces to form between the clothing and your skin. Finally, you must wear a warm hat at all times, since up to 80 percent of your body heat can escape through your head.