Thermal Clothing

Looking to Buy Thermal Clothing?


Thermal clothing is indispensable when you exercise in cold temperatures. As your body warms up, thermal clothing insulates this warmth and employs it to keep you comfortable during your runs. We advice you to always wear thermal clothing when temperatures drop below zero. But a thermal base-layer can of course also be very welcome when faced with chilly winds or icy showers. With good thermals you reduce the risk of injury and illness and by staying comfortable you can keep your focus on your runs. Our thermal clothing collection includes thermal tops, thermal singlets and thermal pants. At 21RUN you can shop thermal base layers for men and women from top brands such as Odlo, Craft, Falke and Gore.

What is Thermal Clothing?


Thermal clothing has two important functions, namely: warming up the body and regulating body temperature. It is important to know that it’s not the thermal clothing that provides the heat, but it’s your body that does. Base layers with a thermal function ensure that the warmth of your body is retained during sporting activities. Thermal tops fit next-to-skin. They ensure that sweat is actively wicked away from the skin and that your body temperature is well regulated. Regulating your body temperature is important during endurance runs or when for instance running a half marathon. At the start of your run your body warms up, but eventually it cools down again. Thermal clothing keeps your body at the right temperature when it starts cooling down.

Thermal Underwear: Innovation and Technologies

Twenty years ago it took five layers to get warm during runs in colder conditions, today you can manage with three or maybe even just two layers. By constantly innovating and by experimenting with new techniques, the thermal clothing industry has developed rapidly in recent years.

Odlo is famous for its innovative technologies that take your sports performances to the next level. Take for instance their thermal clothing with Active Spine technology. This clothing technology encourages you to find the right posture by activating your spine. Or, their Odlo Blackcomb thermal clothing which fits tightly around the skin and functions best in cold and rough weather conditions.

But Odlo isn’t the only market leader when it comes to thermal underwear. Craft thermal clothing has been popular with runners for years. One of the technologies Craft uses in their underwear is their Fuseknit technology. This technology offers an ergonomic fit and thereby knows to provide excellent comfort. Next to Fuseknit, Craft also boasts the Body-mapping technology, which regulates body temperatures like no other thermal clothing technology to date.

Recently, thermal wear has also become suitable for summer. Instead of keeping you warm, the thermals now ensure that you stay cool. Thermal clothing comes in differents types. There is clothing that’s perfect for extreme cold and there’s clothing for extreme heat, and everything in between of course. Just decide what you’ll be needing and take your pick from our enormous collection.

When to Wear Thermal Clothing?

If temperatures are around or below zero, then we recommend you to start considering thermal clothing in a three-layered outfit. A three-layer outfit is made up of a thermal top, a basic running top and a jacket. By adding 10 degrees to the actual temperature and considering what you would normally wear in these conditions is a good way to decide what to wear in which conditions. Because you’re active your body will heat up and what seams chilly at the start, might turn out to be quite hot once you’ve warmed up. When it’s spring and the sun’s out, a regular running top will probably be enough. When it’s a windy day in winter, good thermal clothing might be essential.

Customer Service


In addition to running, thermal clothing is widely used in other outdoor sports such as football, rugby, hockey, hiking or winter sports in general. At 21RUN you can shop clothing from various top brands. Orders from €50 will be delivered to your doorstep for free. Would you like to learn more about thermal clothing? Our team of running specialists are ready to tell you everything there is to know about thermal clothing.