That said, several of today's fabrics are designed to pump moisture away from the skin as rapidly as possible. Look for things made with Polartec PowerDry, which is a "bipolar" fabric, meaning its inner layer and outer layer are different. The inner layer is soft, dense, and designed to "wick" away moisture. In other words, it vacuums moisture up from your skin and carries it to the more open outer layer, where evaporation can work its magic. Mountain Hardwear's Extend Zip T ($60) is made of this stuff; so too is the simpler, short-sleeve REI OXT Zip Top ($32).
Anything with polyester is also good, as polyester doesn't absorb as much moisture as other fabrics, so it dries faster. I really like Patagonia's Silkweight Capilene, such as the Long Sleeve Crew ($34). It's an excellent base layer. And you're doing the right thing by carrying some spare base layers. But a sweaty back is one problem you'll have to endurethe pack will always ensure that your back is soaked. (I once had an old knapsack with a wool felt back pad. Like strapping on a sheep on heat.)
Still, some people just sweat more. The best you can do is control it as much as you can, and learn to live with it.
Our mission to inspire readers to get outside has never been more critical. In recent years, Outside Online has reported on groundbreaking research linking time in nature to improved mental and physical health, and we’ve kept you informed about the unprecedented threats to America’s public lands. Our rigorous coverage helps spark important debates about wellness and travel and adventure, and it provides readers an accessible gateway to new outdoor passions. Time outside is essential—and we can help you make the most of it. Making a financial contribution to Outside Online only takes a few minutes and will ensure we can continue supplying the trailblazing, informative journalism that readers like you depend on. We hope you’ll support us. Thank you.Contribute to Outside →