Clothing – 1st layer (NEW!)
You have plenty of options for your 1st layer, but the priorities are always the same: comfort, freedom of movement, and moisture management over long durations. You’ll try to manage your effort and layers to avoid sweating, but it won’t always work 100%. When it happens, you want a base layer that moves moisture away from your skin and dries quickly.
1st layers range from very thin to more insulating options. The right choice depends on the conditions, how you personally handle the cold, and how the piece integrates into your overall layering system.
A higher percentage of merino wool can help manage odor. That said, merino isn’t for everyone – make sure your skin tolerates it over extended wear. I like merino, but over time it dries out my skin and becomes itchy. It also doesn’t always move moisture as efficiently as synthetics. While it retains warmth when wet, running for hours in a damp layer isn’t ideal. That’s why many brands blend merino with synthetic fibers to balance comfort and performance.
Winter running tights aren’t listed below, but they can work well as a base layer. In milder conditions, they may be all you need for your legs. Just be careful with wind exposure – non-windproof tights can become a liability. You may not immediately notice it, but sustained exposure to cold wind can increase the risk of frostbite.
Other things to consider:
- Does the shirt have a zip collar with a metal puller? If so, does the puller come into contact with your skin (= potential for frostbite)?
- How does your base layer interact with your other layers?
- What’s your drop bag strategy – what are you carrying, and what are you planning to swap out later in the race?
Other options / Things to consider
There is too much product on the market for me to be certain I am not forgetting anything interesting.
One brand that I really like is X-BIONIC. They have an incredible amount of features in their first layers the moisture management is excellent. It’s an interesting option for anyone who can’t use merino wool or wants to complement merino layers with something 100% synthetic.
Another type of product that seems to be on the rise is underwear of things that I have tried are with netting (e.g. Aclima WoolNet). The idea is that is saves weight but does not compromise on insulation because the trapped air also keeps warm. And of course it breathes well and dries quicker.
Saving weight
When it comes to saving weight with 1st layers, the question is not so much about what fabric to use. You will definitely want a thin and a medium weight 1st layer. A thicker layer of Polartec® PowerStretch® Pro™ or similar is also good to have. It’s more about how many sets of underwear you want to take … Ideally, you use your drop bag well for this, i.e. obviously don’t carry the underwear for the entire race with you if you can deposit some in your drop bag. The rest is personal preference. If your sled ends up being too heavy, the quantity of underwear you have with you is something you can re-visit.