Over the past few decades, humans have developed some pretty high-tech synthetic fabrics, including membranes with nine billion pores per square inch and bi-layer wicking polyester.
But in spite of our best efforts, the most advanced technical fibers still come from Mother Nature. Take merino wool, which is hard to beat when it comes to warmth, breathability, odor control, and sustainability
That said, I think man-made synthetics can compete with Mother Nature when it comes to wicking abilities. For high-output aerobic excercise, I prefer synthetics over wool—they're softer and usually more durable.
After testing dozens of baselayers for Outside's Winter Buyer's Guide, I found that most of my synthetic favorites had one thing in common: they used Polartec Power Dry or Polartec Power Dry High Efficiency fabric.
There’s a reason why these fabrics perform so well, and it becomes evident when you take a look at the tech details. Polartec patented a "mechanical wicking process," says Allon Cohne, the company's director of marketing. The technology is actually built into the fabric, so it's not a treatment that will wash out over time.
Polartec's Power Dry fabrics both have a bi-component knit, meaning they’re made from two fibers sewn together. The larger fiber next to your skin grabs moisture, which the smaller fiber then absorbs. Together, they pull sweat off your body. And while both fabrics work very well, Power Dry High Efficiency is slightly more breathable and packable due to its lighter-weight fabric and waffle-grid pattern.
Here are five baselayers I would highly recommend that use either Polartec Power Dry or Polartec Power Dry High Efficiency.
Outdoor Research Torque SS ($59)
I haven't tested another baselayer yet that wicks moisture faster than the OR Torque. The Torque uses a blend of polyester and polypropylene that can dry within 10 minutes of a complete soak through. Note: The polypropylene does get very smelly. The LS version has flaps on the sleeves that can cover your hands like mittens, a nice feature for windy trail runs.
Patagonia Capilene 2 ($49) and Capilene 3 ($55) Crew
Capilene 2 has been my go-to baselayer for much of the last decade. When Patagonia decided to start using Polartec Power Dry last season, I was nervous they were going to ruin a great product. But I was pleasantly surprised to find that the new Capilene 2 is as light and supple as ever, and it wicks better than the old fabric. I would recommend both Capilene 2 and 3, depending on how thick you like your baselayers. If you run hot like me, go with Capilene 2. If you prefer a warmer layer, go with Capilene 3.
Patagonia Capilene 4 One Piece ($199)
I have written about this baselayer many times now. I love it. It just so happens it's a staff favorite at Outside. "There are no gaps in the warmth. I can layer so much quicker, it's one and done," Executive Editor Sam Moulton said when I asked him about his favorite gear from 2013. The Polartec High Efficiency fabric makes this one piece breathe extremely well considering how warm it is. I used this as my early morning skinning layer because it kept me warm without making me overheat.
Eider Blow Half Zip ($150)
This French company makes very high-end next-to-skin baselayers built for high-output activities, and the Blow is no exception. Using mostly Power Dry High Efficiency fabric, it wicks well, and the four-way stretch construction won't inhibit your range of motion. It weighs 7.5 ounces, making it very packable.