Polypropylene is a material that few people are aware of and even fewer know how to pronounce. But more and more performance clothing manufacturers are using polypropylene as a core fabric in their products. These manufacturers tout polypropylene's ability to keep the wearer warm, dry and comfortable during high aerobic activities such as running, hiking, skiing and snowboarding just to name a few. So what would make polypropylene fabrics an alternative to well known products like Under Armour? Polypropylene, like many other synthetic fabrics on the market today is a polymer or a plastic. This means that it is very lightweight and will absorb little if any water and instead repel water. As a result, polypropylene fabrics dry extremely fast. This feature is particularly useful for next to skin products such as socks and performance underwear. When worn next to your skin, polypropylene will stay dry and helps prevent chaffing and keeping comfortable throughout your aerobic activity.

Another very useful feature of polypropylene is it's ability to retain heat. Polypropylene retains more heat than any other fabric. This means that on top of being very lightweight, thermal underwear made of polypro will be warmer than long johns made of polyester or cotton fabrics.

One of the features I like about polypro is that it typically costs much less than other performance products. I can buy several sets of polypropylene thermals for the price of just one Under Armour thermal top. So the next time you are in the market for some performance active wear, you'll want to check the label to see if it is made of polypropylene.