It certainly is counter-intuitive, but keep that long sleeve on. We’ll river wash it for an instant airconditioned effect.

There is a lot of science to it, but the science is an age-tested and desert-proof technique for staying cool. Not only does wearing long sleeves protect you from direct sunlight and sunburn, the right gear will actively work to cool you down.

The guys with the sleighs will tell you; in extreme cold, you stay dry to stay alive. The moment there is moisture to your skin, you lose body heat 20-30 times faster than if you were dry. Add a bit of wind chill and you’ve got yourself a recipe for hypothermia. To affect this cooling system in a hot environment, we apply the principle of evaporative cooling.

In the same way that a layer over your skin insulates against cold, in a hot climate where you sweat, an over layer increases skin surface ventilation and prevents immediate evaporation of sweat from your skin by the sun. This allows for evaporative heat loss as moisture is a great conductor of heat between your skin and the environment. Remember how a bit of sweat cools you down after a run? Now take that shirt and dunk it in the river but keep the trousers dry to avoid the rash.

The reverse applies in a cold climate. If you’ve done any amount of combat survival you’ll understand how important your clothing is in maintaining body heat in a non-permissive environment where you can’t make fire to stay warm during a blackout op. Here layers are the preferred way to retain body heat and there is nothing like elasticated materials such as merino wool or polyester and elastane blends that allow for comfortable layering in cold climates.

Even better when you’ve worn it beyond the point of rustling. We all have those items which we wear time and again, hot or cold, rain or shine. 

C