What Smartwool Doesn't Want You to Know

My feet get really, really cold in Tokyo. They occasionally got cold in the states, but back in Oregon, if it was as cold as it gets in the evenings here (It's 37F / 3C right now), it probably meant I was snowboarding. Most of my body handles the cold fine. I tend to run hot (if a Japanese person is chilly in a sweater, I'm warm in a T-shirt) and layer, and the chill is a non-issue. My feet, though, freeze the minute I step outside, and if I spend a good amount of time outdoors (say, riding to Waseda), they can take half an hour to warm up once I get inside. It sucks.

I tend to believe there's a technological solution to most problems, so I went out searching the internet for a fix for my cold feet. It looks like I might not have the best circulation, but I've got pretty good nutrition and exercise, and I don't overtighten my shoes or use excessively thick socks, so there's not much I can do in that department. Insulated Timberlands or work boots are a possibility, but they're expensive and limited-use. That left socks.

I was looking for the best, warmest sock I could, cruising outdoors sites for reviews, when I happened on a mention of Vapor Barrier socks, and how they leave anything else in the dust when it comes to warmth. Perfect! With a name like "Vapor Barrier," they've got to be chock-full of advanced sock techology, right?

A vapor barrier (VB), it turns out, is not a trademark, but a fancy name for a plastic bag that goes between your skin and your sock. You can buy commercial versions, and they're a little more anatomically shaped, but the basic concept is to put a thin, entirely non-breathable material right against your skin.

At first glance, this goes against everything I've been taught about outdoor clothing. I wear fabrics as breathable as I can, because I know the evaporative cooling from sweat-drenched clothes can give you hypothermia. Why the heck would I want to trap moisture?

The answer is obvious enough that I felt stupid for not seeing it earlier. Sweat only cools you down when it evaporates. As long as you have a nonbreathable barrier between your skin, there's no chance for evaporative cooling to occur. Moreover, the more humid the air around you is, the less you sweat (that's why humidity makes the air feel warmer; your body can't cool itself as easily). A vapor barrier blocks evaporative cooling, maintains a humid climate around your body so that it reduces its sweat, and keeps you comfortably warm (if a little clammy).

I understood this in the abstract but wanted to try it for myself. On the way home from Waseda, I grabbed two mini grocery bags from the co-op, put my feet in them, then put on my socks and shoes. Riding home, I was amazed- I didn't feel the cold biting at my feet and freezing them solid like it usually does. Instead of thinking about frostbite, I could appreciate the amazing sunset on the Sumida river (I really need to bring the camera out to Asakusa in the early evening sometime soon). Taking my shoes off when I got home, my feet were a tiny bit moist, but nothing more than if I'd come back from a jog or taken off hiking boots.

There are places the vapor barrier technique works better than others. Unless you're standing in one place for a long time, or facing very, very cold weather, a VB shirt or pair of pants would be fairly uncomfortable. Your core has great circulation, sweats a lot, and is usually the first part of you to overheat (plus, since VB's go right against the skin, taking it off and putting it on again would be a bear). I've never had problems with cold legs, and with a windbreaker or light jacket, my torso never gets cold. Feet and hands, though, are perfect for vapor barriers. With little muscle mass (hence little sweat) and poor circulation, they are the hardest to keep warm, and when you use a VB, they don't produce so much moisture that it gets uncomfortable. I've been wearing normal leather gloves on the bike, and never had any issues so far, so I haven't done too much testing in that area.

The whole plastic-bags-against-your-skin feeling is not the best (clammy and kind of slippery-feeling when you walk), so my next step is going to be to figure out a more practical VB sock solution. The simplest is to just wear a thin nylon sock right below the barrier, but there are a few companies making cheap VB socks with internal fabric linings, which sound pretty good to me.

A final thought from thebackpacker.com:

So now you ask, "Why aren't outdoor magazines raving about VB's?"
Economics, my friend! Do you think that outdoor clothing manufacturers
would continue to spend tens of thousands of advertising dollars in a
magazine that runs articles touting the virtues of a 5 cent alternative
to the $200.00 – $300.00 whiz-bang parkas being advertised?!
So much for giving my money to SmartWool or Hot Chillys- I'll be riding to school tomorrow wearing two Waseda Co-Op shopping bags under whatever socks are clean, and I'll be happy as a clam.

Vapor Barrier reading.

The article I original read on VB clothing at thebackpacker.com

The Wandering Knight on Ultralight Backpacking Clothing.

Stephenson's Warmlite, specialists in VB clothing.