* Cotton: Depending on where you live, cotton clothing can kill you. Cotton is hydrophilic, meaning it is no good at wicking wetness away from the skin, and can become damp just by being exposed to humidity.
Once wet, cotton feels cold and can lose up to 90 percent of its insulating properties. Wet cotton can wick heat from your body 25 times faster than when it’s dry. What feels like a cool and breezy shirt to you in the hot sun can quickly become dangerous if it cools below 60 degrees at night and your clothes are still wet. In humid conditions, it’s hard for the shirt to dry. People have died from hypothermia in the middle of summer when caught overnight in wet clothes.
cotton fabrics may not be the best choice for particular survival conditions
Both of these 100% cotton garments would keep you warm until they got wet. Then, this clothing can become dangerous to wear!
COOL OFF: On really hot days in a canoe, a cotton shirt can be soaked with water, and worn to cool you down. On a hot, desert hike, you can prevent heat stroke by using a few ounces of water to wet the shirt down. (The water can come from anywhere and doesn’t have to be clean just to use for evaporation.
If necessary to conserve water in an emergency, you can pee on your shirt to wet it.) Just make sure to have another dry shirt with you to change when needed. Because once the cotton gets wet, you could end up in trouble.
Don’t be mislead by the looks and camouflage patterns of 100 percent cotton hunting clothes. These garments may be just fine for a hot, September dove hunt in Mississippi, or unseasonably warm deer hunt in November, but they become cold and clammy when damp or wet. And after sundown you could be mighty uncomfortable. I recommend a wool or polyester blend.
* Polypropylene: This material doesn’t absorb water, so it is a hydrophobic. This makes it a great base layer, since it wicks moisture away from your body. Athletes swear by it since they need the sweat to get off the body as fast as they work it up. For outerwear, there’s poly fleece but it’s not really that warm, unless used as an under layer. The bad news is that polypropylene is made from plastic and it melts, so a spark from the campfire may melt holes in your clothing and burn your skin.
* Polyester: This is essentially fabric made from plastic, and it’s good stuff for keeping you toasty warm by holding in heat. The material has good insulating and wind stopping value, and can be made into many different thicknesses. Many running shirts are loose-weave polyester and they’ll wick away some moisture while providing a windbreak against the chest. But the shirts tend to stain under the arms, and oil stains won’t come out.
* Nylon: The fabric is pretty tough and can be used as your outer layer. It doesn’t absorb much moisture, and what does evaporates quickly. It is best used as a windbreaker, to keep your clothing from being compromised by the wind and light rain. It’s great fabric for a poncho.