Tuesday, February 01, 2011

Gear for cold-weather running

(Today on my run: A quick Monday morning jaunt up to South Sentinel Summit. The temperature was -5 degrees with light windchill. I was wearing most of the clothing I'm blogging about today, staying comfortably warm but a little too sweaty. Plus, my hat got soaked. I wonder how that happened?)

“How do you dress to go for a run in the cold?” To me, this is as multilayered a question as “what type of bicycle should I buy?” There is no one-size-fits-all answer. Just asking what the temperature is won’t work. You need to ask whether it’s night or day, and whether there’s wind, what's the wind speed, and which direction is it moving. Is it sunny or overcast? High intensity, mid-intensity or low intensity activity? Packed snow or powder? Is new snow a possibility? Rain? There are really a lot of questions to ask, but I think people often forget what I believe is most important one — how long are you going to be outside?

Certain types of insulating clothing can often protect against a wide range of weather. But there is a monumental difference in a body’s needs when you add time. I can complete my 20-minute bike commute to work when it’s 10 degrees outside wearing only jeans, regular shoes, a cotton hoodie, thin shell, hat and fleece gloves, and still feel fairly comfortable when I arrive at work. But if I was going out for an eight-hour bike ride in 10 degrees, you can bet I’d be encased in fleece and Gortex, with huge winter boots and three layers of socks. If I wore my commuting clothes on an endurance ride, I would probably die. But why is something that’s good enough for 20 minutes not good enough for eight hours?

It’s probably both a simple and complex answer, but I think of it in simple terms. Take a 98.6-degree bottle of water and put it out in the cold. It doesn’t instantly cool down. It takes time, although the rate of cooling accelerates as temperatures become colder. Eventually, the water is going to freeze. Bodies react in a similar way. Humans have the added benefit of thermoregulation, which despite typical cold-weather complaints from our whiny species, actually works very well. Bodies want to maintain homeostasis and will do everything in their power to keep it, from burning up glycogen stores to burning body fat (although this is of course the heat equivalent of burning kindling versus old-growth wet logs. If your bonk in the cold and can’t recover your calorie stores quickly, your risk of hypothermia increases exponentially.)


But the problem remains — bodies start out warm, and because thermoregulation isn’t a perfect system, will eventually cool down over time. Physical activity helps stoke the furnace (like gasoline on kindling.) But even with an unlimited source of calories, muscles and motivation wear down over time, and the body is forced to slow to a more sustainable pace (big logs, slower burn.) Therefore, the practical way to dress for long periods in the cold is to start out as lightly dressed as possible, burn through the kindling, and then add layers to protect the slow burn as the body cools down.

It makes sense in theory, but in practice, I detest the layering and de-layering process on the trail. I like to keep moving, so I tend to start hot, shed an excessive amount of sweat, and then fight for hours to keep my suddenly damp furnace from fizzling out. Simple folk logic dictates that "sweat kills," but it's never a cut-and-dry situation. There are degrees of manageability, especially when sweat gathers and refreezes on the inside of a Gortex shell, where it limits the fabric's (dubious) breathability but otherwise doesn't do much harm. It’s certainly not ideal but I manage to make it work for me most of the time, by favoring moisture-rejecting synthetic layers and vapor barriers. I can wring the warmth out of lightly damp fleece layer for eight or 10 hours, but as I learned last year in the White Mountains 100 and previous Susitna 100s, this doesn’t work so well for 20 hours or more. As time burns on, my body just keeps cooling, and after a while I am just really, really cold.

And again, this is all combatable by adding more layers, of which I am always carrying a few spare. My situation has never been dire, but I am always on the lookout for a system that’s fairly adequate for not only a wide range of temperatures, but also a longer period of time, without changing clothing or starting out too cool and never getting the furnace going in the first place.

Thus, my “one-size-fits-all” Susitna system for a decidedly not-one-size-fits-all world. This is an event that, if I finish, will take at least 30 hours and as many as 48, in temperatures that could range from -40 to +40 degrees, from dry Arctic cold to rain. Temperatures will likely fluctuate ~30 degrees or more during the event, and I'm more likely than not to see some precipitation.

Outdoor Research Gore-tex jacket: In the past few years I have gone from embracing Gore-tex to shunning it to embracing it again. I learned in 2006 that one must have to option of being completely waterproof during the Susitna 100, because it can rain a lot. Also, this jacket accommodates my layering laziness with two hem-to-bicep waterproof zippers, which allow me to essentially turn this jacket into a poncho if I need to do some serious sweat venting without the inconvenience of actually have to take it off. Plus, it blocks wind completely.

Skinfit waterproof pants (I’m just guessing with this link because the Web site is in German): Beat gave these to me after I brought a cheap pair of rain pants on our backpacking trip in Yosemite. They have a full-length zipper, so they can be applied without removing shoes, and the zipper can also aid in venting if needed. Windproof, waterproof, awesome.

North Face Windstopper tights: I bought these large enough to add a layer of microfleece tights underneath if needed. But even at -10 degrees, they provide a lot of warmth and wind protection while still venting moisture fairly well.

Sunice Alana Fleece Pullover: I won’t start out wearing this layer unless temperatures are quite cold, but it will offer the option for quick and effective insulation during slower-burn periods.

Underarmor Evo base layer: I’ve been using these shirts on a regular basis for three years, ever since my youngest sister bought me one as a birthday present at Nordstrom’s. It's always strange to receive a favorite piece of gear from your fashion-conscious sister, I don’t see any reason to change now.

Vasque Mercury Gore-tex shoes: Feet are warm and snow is cold, which can lead to melted snow and wet shoes and cold feet. Thus the waterproof shoes. I got a women's size 10 — 1.5 sizes too large — to accomodate lots of insulating socks. Comfortable and warm.

RBH Designs insulated VaprThrm socks: A full vapor barrier retains heat and moisture to keep shoes dry and feet warm. It's impossible to fully expel moisture in these kinds of conditions, so it's best to keep it contained.

Drymax socks: I realize that 100 miles of anything is going to wreck feet, and the only way to mitigate this is to keep them dry. Since the vapor barrier socks combined with Gore-tex shoes will retain most of the sweat moisture, I'm hoping Drymax will help hold it away from skin. I know there will be moisture against my skin, but in all of my testing, so far, so good. I will carry several of these so I can change frequently, as well as polar fleece and wool socks as backup insulation layers. Can't be too careful with feet. Blisters suck but frostbite is worse.

Mountain Hardware Microdome Beanie: I like this hat. It's warm and it doesn't make me deaf like my other Windstopper hat.

Pieces of gear I haven't yet dialed in exactly yet are a down coat, knee-length waterproof hiking gaters, several pairs of liner gloves, mitten shells, light balaclava, neoprene face mask, heavyweight balaclava, goggles, and the big one — a hydration system. I'm going to play with a few more options before I dial that one in. But the preparation is half the fun! (Not really, but I tell myself this because otherwise I have a bad habit of cobbling stuff together and hoping it works out. This is why I commute to work in cotton hoodies.)