Ah, the baselayer. Quite possibly the single most important piece of your winter running wardrobe. This is the piece that makes or breaks your run during less than ideal weather conditions, whether it be snow, aggressive windchill, or bitter cold.
Three main things you should know about a baselayer:
made from knit fabric, which gives them stretch in all directions and breathability
fits snug to the skin, serving as your first defense against cold and moving moisture off the skin
generally made from a polyester, nylon or wool blend (COTTON IS ROTTEN)
So a baselayer is the epicenter of your running wardrobe world. It manages the combination of cold air, body heat and sweat, allowing you to run comfortably throughout the winter months. Here’s a primer:
Your CORE warms your whole system (bloodflow originates here), so you want to make sure it is properly insulated. You put on your comfy baselayer, which fits close to the skin on your core.
As you get into your run, you will begin to PERSPIRE (even when it’s cold out). This is because your body is working hard, causing your base internal temperature to rise. Your body then works to cool itself by sweating.
Your baselayer grabs that moisture and takes it right off your skin. The baselayer brings the moisture to the surface of the garment, allowing it to EVAPORATE. Because the baselayer is made of synthetic material, it dries quickly.
Here’s why cotton is rotten: it ABSORBS and HOLDS moisture. So when you sweat, that moisture just sits on the garment, against your skin. And guess what happens when it’s cold out? That wet cotton shirt gets COLD. Imagine holding a cold, wet t-shirt against your skin for the duration of your run. YUCK.