What's wrong with this picture (aside from the designer shades, silly hats and fake lens flare, that is)? These backpackers are wearing head-to-toe cotton, a perfectly reasonable everyday fabric that, when worn into the backcountry, could be the death of you.
Let’s face it: We're not the hairy, robust hunter-gatherers our distant evolutionary ancestors were. For those of us craving the bite of crisp air at sunrise, or the crunch of grass beneath our feet and green canopy overhead, that may be a strangely bitter pill to swallow. Our bodies just aren't as rugged as they used to be.
Plenty of Chemical Age textile innovations have been developed to deal with this problem, allowing us to withstand freezing cold temps and every other kind of inclement weather while we explore the outdoors. None of that matters, though, if you wear that weathered pair of jeans or lucky white T into the woods. Simply put, don't wear cotton on your next adventure—it could be a death sentence.
If you’ll excuse the hyperbole for a moment, consider that cotton is a hydrophilic fabric, meaning it easily absorbs moisture and dries very slowly. This means that when the going gets hot, your cotton clothing soaks up your sweat and clings to you like cellophane. Throw in a few drops of rain, kick up a little wind for good measure, call it sundown—or, worse still, winter—and you’ve got all the ingredients for hypothermia.
It’s not only cold, wet cotton you have to worry about, either. Even if you manage to keep your cotton-wear dry and off of your skin, it’s still highly combustible. Catching on fire always ruins campfire tales.
Modesty aside, the entire point of clothing is temperature regulation. While synthetics and wool tend to be a bit pricier, you’ll definitely thank yourself for shelling out (pun intended) when you're warm and dry in the wilderness. By opting for a well-planned layering system, it’s easier to beat the elements.
You’ll want to choose your layers depending on the season, but a good rule of thumb is that your layers should get less porous as they work away from your body. So, start with a breathable base layer and work your way out to a waterproof shell.
It’s not easy to keep your body hovering at its baseline temperature of 98 degrees, but by having layers you can manipulate, it’s easier to respond to external stimuli. If you begin to heat up, shed a few layers. Usually following this is a sudden, inexpressibly irritating chill, in which case you should layer back up. Also remember that a little "nip" before the trip is OK—your body will quickly warm up once it gets moving.
As far as what’s made of what, and where to wear it, polypropylene base layers do well pulling moisture off the body and drying quickly. A closely related, though pricier material is capilene. The layers following should pull from polyester, fleece, nylon and wool. They’re durable, dry well, and have hardy insulation. As for the outer shell, Gore-Tex does wonders. By allowing sweat vapors to escape while blocking water molecules from penetrating, it keeps you high and dry.
If you really want to wear something cotton on your next adventure, bring along your favorite bandana. On a hot hike, nothing feels—or looks, for that matter—cooler then a wet rag tied around your neck.