Trying to decide which type of thermal underwear is best often leads to thoughts about deep winter blizzards and hypothermia. Spring comes along and you stuff your base layers in the same storage bin as your heavy coat and snow gloves. When it comes to your spring and summer recreation, It's time to change your thinking about what thermal underwear is and when to use it.

Consider almost every other fuzzy animal that lives and dies based on its fur coat. When warm weather comes they don't shed every strand of hair and bask in the warm sun with no fur at all. Instead they shed their heavy winter coat and establish a lighter layer of fur to protect them from moisture, wind chill, and even the burning sun. So why do we humans suddenly ditch our common sense and put on a thin layer of non-insulating material as if that is the best option?

There are multiple lightweight or silk weight options that will expand your options beyond the cold temperatures of winter. The Duofold Varitherm Silk Weight thermal is an excellent example. It has a single layer, dri-release, poly/cotton blend that is designed to be worn during cool or warm weather. This makes it a realistic option 365 days per year. Silk weight thermals come in a variety of options including long sleeve, short sleeve, v-neck, tops and bottoms to suit your preference.

Many people want the insulating properties of thermal underwear without sacrificing the comfort they know and love from the feel of cotton. You don't have to shy away from cotton based thermal underwear under the assumption that it doesn't have the moisture wicking properties of wool. There are many cotton/polyester blends that will dry much faster than 100% cotton fabric. The cotton/poly blend also provides a wider variety of colors and styles including white, blue, black, red, camo patterns and more. Most of all you'll notice the considerable price difference in sizes for adults and even children. Many of the thermal underwear options on Outersports have been reduced in price due to the change in season. Don't miss out on a great opportunity to get the thermal base layers you need for any season or occasion.

With temperatures lingering at a frosty 19 degrees you would think that most would cuddle up next to a warm fire and hide. But for one amazing mother in Utah, her fire seems to come from within!

Shawna, of NatureForKids.net, shows that with the proper cross country ski wear, and a touch of scenic beauty, you can get outdoors and enjoy nature even on the coldest of days. She exemplifies the model family camper who isn't afraid to take her children along with her. Knowing how to be prepared with the right thermal layers gives her more confidence and comfort to do what she loves. What does Shawna love? She loves cross country skiing around a high altitude reservoir outside of Brigham City, Utah.

It was no surprise to see her sporting some high quality ColdPruf Extreme Performance Thermals under her coat. Most of all she loves the comfort and bargain of her Merino Wool Outdoor Trail Socks.

In regards to the Merino Wool Trail Socks - Shawna says, "First thing I noticed was how cushioned they were. They fit snug and the seams aren’t bothersome at the toe. They’ve kept my feet warm enough that I haven’t had to give them a second thought while outside."

You can read the full experience, review, and get to know Shawna on her blog by visiting: Nature For Kids

100% Polypropylene - History and Uses

100% Polypropylene underwear has been around for quite some time. Polypropylene was developed in the 1950's. When it was realized that polypro absorbed very little water and retained heat extremely well, it was spun into a thread for use in thermal underwear. Polypropylene has been a very popular performance thermal ever since. It has become a staple for many outdoor industries where the user is exposed to cold wet climates. Cruise liners traveling through the Arctic or Antarctic request that travelers wear polypropylene thermal underwear as a base layer because of its' ability to retain heat better than any other fabric.

U.S. Navy and Coast Guard wear 100% Polypropylene Thermal Underwear

Polypropylene is also very light weight. Available in a thick fleece knit, 100% polypropylene thermal underwear only weighs a fraction of what cotton thermals with the same temperature rating would weigh. One unique and highly desirable feature of 100% polypropylene is the ability to retain heat even when it gets wet. I have a friend that has run river rafting tours on the Colorado River where it winds through The Grand Canyon. One problem river guides have faced over the years is hypothermia due to constant exposure to the cold river water. My friend says he wears polypropylene thermal underwear as a base layer because it is excellent at keeping you warm in cold water. Instead of the cold water sucking the heat away from  your body, the polypropylene insulates you and keeps your body's natural warmth next to your skin.

Polypropylene Thermal Underwear Mandated for Navy and Coast Guard

This leads us to the title of this article. All of the properties I've mentioned so far make 100% polypropylene ideal for the U.S. Navy and the U.S. Coast Guard. Dive and rescue teams that will be entering the cold ocean waters are required to wear a base layer of 100% polypropylene underwear underneath their dry suits. OuterSports has a contract with the U.S. Government to sell polypropylene thermal underwear in bulk to The U.S. Armed Forces. The U.S. Coast Guard and U.S. Navy typically has Outersports supply them with the high quality Coldpruf 100% Polypropylene Thermals. There are many different brands you'll find polypro thermals in. But the Coldpruf brand has a much softer hand so it feels great worn next to your skin. OuterSports also carries 100% polypropylene thermal underwear in a thick two layer fleece. This is used as part of the Extreme Cold Weather Clothing System or ECWCS by all of the U.S. Armed forces. Like its' name infers, the thick fleece polypro part of ECWCS is great for extreme cold. The first rule of thermal insulation is that the more air a fabric is able to trap the better it will insulate and the warmer you will be. Polypropylene in fleece form traps more air while the fabric itself retains more body heat than any other fabric. I love to wear the fleece polypropylene thermals when I go out snowmobiling on colder days so I don't have to worry about getting cold.