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Gear Guy

Can synthetic underwear really keep me cooler than cotton?

I have worn Patagonia Silkweight underwear for years, but I’m still not sold on “evaporative cooling.” And this summer I’ll be backpacking in the Middle East, where temperatures are frequently 100-plus degrees in the shade. Can anything really keep my nether regions as cool as cotton? Michael Alexandria, Virginia

A: Backpacking in the Middle East. Wow! That’s going to be interesting (I mean that in a good way).

Patagonia Silkweight T-shirt

Silkweight T-shirt

I don’t think any fabric on earth is going to keep you all that comfortable, but I’d still vote for synthetics in most cases. You’ll find they simply dry much faster than cotton, as well as being less inclined to develop and give off a bad odor when you’re unable to do any laundry. And, I’m completely convinced that fast-drying actually does help cool you through the evaporative cooling process.

So, yes, I’d pack Patagonia Silkweight T-shirts ($32) and boxers ($26; Also, you could try some items made with CoolMax ($20 at L.L. Bean; Ex Officio ( makes some excellent wicking, fast-drying underwear designed for hot, sweaty travelers. Briefs are $18, boxers $24, in several styles.

I’m not completely dogmatic on this point, and chances are, if I were making this trip, I’d pack in some cotton T-shirts and maybe even a few pairs of cotton underwear. I don’t dispute cotton’s comfort in hot weather; I just think it has limitations, especially for long-term wear.

Otherwise, I’m sure you know the drill: Keep your head protected, drink plenty of liquids, and try to avoid hiking during the hottest part of the day. You’ll actually adapt pretty well to the conditions if you don’t rush things.

The votes are in: Check out the winners of Outside's 2006 Gear of the Year awards, including the year's hottest backpacks, sunglasses, and digital cameras.

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Filed To: Base Layer
Lead Photo: courtesy, Patagonia