Dressing to kill can have a very real, very chilling meaning when applied to people who are exposed to the elements for long stretches of time. Indeed, hiking expert Jeff Alt is blunt about the possible ramifications of wearing cotton clothing: It can kill you. "Cotton retains moisture and can lower your body temperature causing hypothermia. Dress in layers of synthetic clothing and have a rain parka," he says.
When Alt hits the trail, he limits himself to just two outfits -- the one on his body and the other in his pack. Alt points out that more recently developed clothing can protect against the sun and stench. "Some of the latest clothing has UPF protection and antifungal agents that decrease your awful smell," he says. "As a rule of thumb, long distance hikers stink. Always stand up wind from a thru-hiker."