Look for apparel that uses 37.5 Technology, which is designed to help keep your body at its ideal core temperature of 37.5 degrees Celsius and the microclimate next to your skin at a relative humidity of 37.5 percent. When you’re hot, the active particles that are embedded in the fabrics remove moisture in the vapor stage before liquid sweat forms, cooling you off. When you’re cold, the same particles trap heat and return it to warm you up. When you’re ready to go outside, keep these basics of layering in mind—and you’ll find that you will be a lot more comfortable and prepared for the worst.
The Art of Layering
Head to toe, you need to consider temperature regulation, moisture management, and keeping a variety of layers available to adapt to changing conditions. Shorter outings at lower elevations will require less preparation than packing clothes for all-day outings. Start with a base layer top and lightweight, breathable shorts. Depending on conditions, carry a lightweight shell top (like this one from Dahlie) as well as an insulating layer. Shell tops can be entirely waterproof or treated with DWR for lighter protection. Insulating layers can include merino, fleece, or a synthetic long-sleeve top. Don’t forget about your feet—sweaty feet are just begging for chafing and blisters. Look for socks that are quick-drying as well as aiding in temperature regulation—like these from Point6.
Consider Activity Type, Level, Length, and Conditions
Before you get dressed, check the weather for your intended location and predicted time outside. Heading out for a midday run or bike ride in 90-degree heat? Dress in a light-colored, lightweight top and bottom. Planning a full day in the mountains with thousands of feet of elevation change? You’ll need to carry an extra layer or two with you, ideally one for insulation plus a waterproof option. Out on the water? Bring an extra layer in case the weather turns. Remember, no matter how pleasant the forecast looks, weather in both mountainous and aquatic regions can change almost instantaneously. It never hurts to be more prepared.
Worn Layers Will Change Based on Activity Level
Exercising at a high output will increase your heart rate, which brings your body temperature up. 37.5 Technology will help maintain an ideal core temperature, but it’s important to keep exertion level in mind as well. Hiking hard to the top of the mountain will require a higher level of effort than the descent. Starting with the minimum layers and not allowing yourself to get drenched in sweat will make for a more pleasant descent. Once you hit treeline, the clouds come in, or you begin lower-output activity, throw a shell or mid-layer on to mitigate the external temperature changes as well as the core temperature changes brought about by the change in activity level and conditions. For rigorous activities like trail running, mountain biking, and alpine hiking, it’s good practice to start underdressed, with your body a bit cold. You’ll quickly warm up once you start moving. For cycling, this temperature-regulating base layer from Bontrager is a good bet. For running or hiking, this top from Salomon will help keep you cool.
Stay Warm to Avoid Hypothermia
Sure, hypothermia might not be the first thing on your mind when you take off on a warm day in the backcountry, but consider your location and how fast conditions can change in the mountains—and even low-lying environments. Any time the body’s temperature drops below 95 degrees Fahrenheit, hypothermia can set in. Instances of hypothermia have been known to be higher in the summer than in the winter months, especially at higher elevations with extended/unexpected precipitation, and in water sports.
Moisture-managing materials are a must for next-to-skin, and a non-down insulating layer, (fleece or merino)—like this First Lite hoody—thrown in your pack is imperative for longer outings, along with a waterproof shell. The shell not only keeps you dry, but it also helps trap body heat and keep your core temperature at a safe level. For hiking or backpacking, this merino short-sleeve top from dhb will work to remove sweat, aid in thermoregulation, and insulate if the temperature drops.
At the beach, most people remember their sunscreen. In the mountains and on the water, it’s just as important. In fact, at higher altitudes, you’re likely to burn faster. In addition to the sunscreen, wear lightweight layers with an element of sun protection. If you have sensitive skin, consider a specific sun-protecting layer, like gloves or sleeves from Eclipse Sun Products that will keep you protected during extended exposure.
Spending time outside can be a lot of fun. With a little planning, you can be sure it stays that way on any activity you plan.
Written by Matcha for 37.5.
Featured image provided by 37.5 Technology