I've long wanted to talk about sports underwear, and this is a good opportunity to discuss it with everyone.
Not long ago, I had a chat with a fashion design friend about how people abroad care more about their underwear choices than we do in China. In terms of brand, material, and tactile feel, we tend not to pay as much attention to our undergarments. I agree with this statement—Chinese people indeed focus more on outward appearances than on what's underneath, which is also one of the micro phenomena of the broader era China is in.
Usually, when beginners start skiing, they think more about looking cool in their ski pants and jackets, but they often overlook the choice of the most intimate and experience-defining item: the base layer. I’ll briefly share some thoughts, and everyone can join the discussion.
Now, talking about the niche world of skiing, the current mainstream ski underwear market can be roughly divided into three types: 1. Polyester nylon-based quick-dry fabrics and blends 2. Merino wool blended with various ratios of synthetic fibers 3. Patented fiber materials like X-BIONIC and SKINS.
The first type of material is the cheapest, with low weaving requirements, resulting in low prices and easy availability. From Decathlon to Taobao malls, you can always find European brands’ OEM products or items from big-name brands. Higher-end options include things like Patagonia’s C3 series.
The second type of material is currently very popular abroad. Merino wool fibers with a diameter of less than 18 microns have an excellent tactile feel, not much different from cotton. So wearing wool next to the skin for outdoor activities won’t cause any prickling discomfort—rest assured. In Beijing winters, my base layer is made of 16-micron Merino wool, and I rarely wear cotton anymore (cotton also has its physical drawbacks, which I’ll mention later). New Zealand has a dedicated wool bureau in Beijing, and ultra-fine Merino wool is an important textile export for them. They are actively promoting this natural and eco-friendly fabric. First, the structure of ultra-fine wool fibers can effectively trap air, providing thermal insulation through air layers. Another important factor is that it’s made entirely of natural proteins, which can naturally inhibit bacteria and prevent unpleasant odors (someone asked me: “Can you wear wool socks for 15 days without washing and they won’t stink?” Ha, definitely not as smelly as cotton socks!). This material suits all ages and can be used both functionally and casually.
But if the fabric is 99% wool, that’s a disaster—why? Because it lacks physical strength and is too soft. To increase durability, manufacturers must blend in some synthetic fibers, which also helps with special weaving techniques to create underwear that fits the body’s anatomy. Typically, socks with 90% Merino wool feel great, but they may pill. However, I don’t think that’s a serious issue. If you want the fabric to resist pilling even after repeated washes and stay smoother, you’ll need to increase the proportion of functional fibers—for example, Smartwool socks usually contain about 70–80% wool (Smartwool is a brand that entered China early; actually, there are many foreign wool outdoor brands, but I personally prefer to check out smaller family-run brands abroad—their quality is also quite good). Premium materials like these are occasionally used by big names like PRADA, though of course at sky-high prices. PRADA has also used Gore-Tex material for street-fashion crossover trench coats.
The third type is the new generation of compression functional underwear represented by X-BIONIC, developed based on research results in human bionics. You can just search “X-BIONIC bionics” online—the entries are maintained officially by the company, so the information is comprehensive. I want to focus on the material. First, X-BIONIC’s patented fibers are hollow, allowing them to store sweat effectively. This design stems from X-tech’s parent company in Switzerland completely overturning the decades-old quick-dry technology. “Quick-dry clothes”—“completely get rid of sweat?”—that was the old way of thinking. Now, it’s changed.
First, you need to understand why the human body sweats: sweat is essential for maintaining a constant body temperature of 36–37°C (36–37°C? Yes, because the human body’s structure means different parts operate at different temperatures during activity. If they were all the same, I’d send you straight to the Chinese Academy of Sciences for research). When a lot of sweat is released, it cools the body—the liquid cools down, and when the body feels cold, the pores contract and stop releasing sweat to maintain a 37°C constant temperature. But here’s the problem: what if you go from cold to hot every few minutes within just 10 minutes? Aside from skiing, the most common scenario I encounter is squeezing into the subway in winter—freezing outside, but once you’re in the subway car—it’s stuffy and hot. Wearing all-cotton underwear in that situation is a disaster. The same issue often comes up while skiing, and even during long-distance aerobic exercise. This problem in sports also leads to another issue. According to Swiss lab research, during physical activity, the body needs to ensure the temperature doesn’t exceed 37°C or drop below 36°C (hypothermia). If that happens, the body will divert up to 80–90% of its energy just to maintain temperature. Your muscles will say: “Who took my cheese? Where’s my energy?” It turns out it’s all going to maintaining body heat. Will you still have the strength to keep exercising? In summer, it means dehydration and fainting; in winter, it’s hypothermia, which affects your skiing experience. After intense activity, rapid sweat evaporation from quick-dry underwear can cause your body temperature to plummet sharply. That’s when quick-dry underwear fails.
Tip one: Remember last winter when it was –30°C with strong winds in Chongli and we went skiing? A friend of mine happened to be at the mountaintop that day. While others were freezing their butts off, he stood there completely unfazed. Someone asked, “Dude, aren’t you cold? You’ve got great stamina!” My friend replied, “It’s not about stamina. What era do you think this is?” (He unzipped his ski jacket) “I’m wearing this. Who’s relying on stamina in weather like this? It’s all about gear!” (He was wearing high-insulation base layers). The questioner immediately headed down the mountain to warm up.
Tip two: A friend was doing a fast run down the slopes at Wanlong—why fast? Because of an urgent need… yep, he had to pee. He was so focused on skiing downhill that he ended up peeing… then kept skiing down to the restroom. Thanks to the enhanced moisture-wicking of the base layer, his pants were almost dry by the time he got there…
So, from the perspective of clothing equipment, the characteristics of skin managing sweat need to be transferred to the most intimate and decisive layer (the base layer). This helps with oxygen supply to subcutaneous veins and reduces muscle oscillation during movement (which can waste extra energy in some cases), stabilizing muscles and ligaments to act like a second skin. Therefore, the base layer needs to have a certain degree of compression. The Energy series, part of X’s high-compression line, is extremely elastic with distributed compression (some...runningcompression pants offer full-wrap high compression) can help stabilize muscles and promote blood flow while maintaining comfort.
Download attachment (110.49 KB) Understanding Underwear Functionality
Borrowing someone else’s hard work, here’s a breakdown of the structural design of an Energy-enhanced top. Each of the English phrases above represents a patented design by X.
3D-bionic sphere is a really interesting design—it’s the reinforced triangular zone on the chest (even the simplified Energy series includes this functional area). Based on human bionics, the upper body areas that generate the most heat and sweat during movement are the heart area on the chest and the lung area on the back. These also show up as hotter zones in infrared imaging. To balance body temperature, this special design is used. I need to explain the principle from the fabric’s cross-section—it essentially creates a clever mechanism for sweat evaporation and contraction of the skin.
Part2 13-10-31
One of the three yarns is a patented silver-thread yarn (winner of the 2010 IF Industrial Design Award) with bio-conductive properties that reflect body heat. This silver thread also has strong antibacterial properties. Columbia Outdoor Apparel in the U.S. has a heat-reflective technology that shares origins with the Swiss X-tech parent company X-tech—they have a technical partnership. The heat-reflective features are similar to those of the Energy-enhanced underwear, offering even stronger insulation. However, according to feedback from friends, the fibers are slightly thicker and stiffer. Of course, that varies by individual. Comparatively, the Energy-enhanced version is perfect, with very high sweat-wicking efficiency.