Keeping Cool in the Cold

The temps have finally dropped out of “unseasonably warm” fall temps into the “seasonably cool” temperatures we expect in winter. I just finished listening to a PBS meteorologist try to explain the difference between astronomical winter and meteorological winter and even he got confused listening to himself! Meteorological winter includes the months of December, January and February, while astronomical winter includes the months between the winter solstice on Dec 21st and goes until the spring equinox on March 21st. The reason for the difference in the dates is that it takes a while for world temperatures and weather patterns to respond to the changing angle of the sun and corresponding amount of solar radiation available to hit the earth. The fall equinox on Sept 22 is the time when day and night lengths are nearly exactly equal over most parts of the world. In the northern hemisphere this is when our temps begin to cool through October and November and finally settle into the reliable “seasonally cool” pattern in December and throughout Jan and February until the day lengths begin to outcompete the nights, ending with the spring equinox. The astronomical winter begins after the changing angle of the sun’s rays have already affected the daily temperatures and when daylength is at its shortest point, well after temps have fallen significantly. Whichever method you use to determine when fall ends and winter begins, the reality is when it’s cold, it’s cold and cold means winter to most of us! Now’s the time to think carefully about how to spend time outdoors without exposing yourself to the danger of hypothermia, the often-lethal drop in core body temperature.

As daylight gets increasingly shorter, we are forced to squeeze outdoor activities into shorter and shorter periods of daylight before and after work. Eventually, there is no daylight time between getting up and leaving for work or between leaving from work and getting home. What’s a person to do to stay sane? Options can include using an indoor exercise regime such as an indoor bike trainer, elliptical machine or whatever other device you prefer, and while this method is great, there is something about being outdoors that makes a huge difference in overall sanity and mental health.

In my opinion, if you are going to do outdoor activities in the dark, it is much safer to do them in the morning hours when you are assured that the temperatures and light levels will increase during your activity. Evening activities seem much more dangerous because if something were to happen, you might be stuck in conditions that are guaranteed to only get colder and darker for an extended number of hours. I have written previously about things that you should carry with you on winter expeditions including fire starter, communication devices with plenty of power, exothermic warming packets and lights, but I wanted to talk about the most efficient way I have found to dress when going out on early morning excursions when its black-out dark and in the teens or 20’s. I’ll admit, it’s hard to leave a warm fire and artificial light to answer the call of those begging dog eyes asking for a walk, but once you learn do dress appropriately for your body’s metabolism and know what to expect, it’s a great start to any day.

Here are some things I have learned about my ideal way to reasonably combat the cold and dark of winter mornings and relatively safely go out into a pitch-black frozen forest for a daily dog walk.

Lighting: I have small bike lights strapped to my hiking sticks to provide about an eight-foot circle of light around me which feels like a safe light bubble to travel in. I have two lights on the sticks and a spare flashlight in my hip pack plus the phone light if all other light sources go out. Headlamps also work well to light your way but be sure you have a backup source of light. As silly as it might sound, my dogs wear lighted collars which both keeps them visible to me and does give them some increased trail visibility of their own.

Sound: Although sneaking through a dark forest on silent feet sounds amazing and exhilarating, the probability of startling a big game animal or predator makes this not such a romantic idea. I have trail bells on my sticks and try to make a bit of a racket as I move along, warning whatever living that might be out there that we are coming. This also keeps the dogs from startling small animals and disappearing on the chase into the dark.

Protection: the best form of protection is having a dog or two…or three, paying attention for you, but you need to stay alert to their body language. They will alert to a danger well before vocalizing with growls and barks. Pay attention, protect them and yourself by calling them close when they alert and remain cognizant of small sounds than could indicate other animals moving. My dogs have been so focused on reading “pee-mail” that they miss entire herds of elk moving nearly silently past. All of my dogs know that the yip of a coyote is automatically a signal to draw close to me. I do carry bear spray on my belt, but if you are not alert to signs of what might be going on around you, it might be too late to deploy the spray if you startle something. Winter feels a little safer because our bears are not normally out wandering around after hibernation begins, but still…

Clothing: I remember that Bear Grylls, the British adventurer and survivalist, said that the one thing that you should NEVER do in the cold is to allow yourself to sweat. He reiterated this over and over and it has stuck in my mind ever since. NEVER allow yourself to get sweaty in the cold. Cold sweat is a death sentence because the act of sweating is the body’s way of reducing cellular body heat and maintaining homeostasis. Your muscle cells obviously require energy to function and part of processing that energy is heat production. Built-up heat triggers your body to react by producing sweat with the goal of that sweat releasing heat through the process of evaporating from your skin surface. It takes energy input to change liquid water to evaporated gas and it’s that heat energy your body is trying to shed. If you are wearing too many/too thick layers of clothing, the sweat travels into your clothing by capillary action rather than evaporation and soaks the clothing fibers rather that releasing the body heat. Continued exertion puts you into a cycle of overheating, sweating and soaking your clothing. When you eventually realize that you are too hot and try to cool yourself in other ways or eventually stop exerting yourself, you are locked into wet clothing that cannot keep you warm and you involuntarily begin to cool with no way of reversing this. NEVER allow yourself to get sweaty in the cold. I have found that a moisture wicking underlayer paired with a heat reflecting outer shell is more than sufficient on days when the temps are in the 20’s or 30’s. When temperatures are the teens, I wear a relatively thin neoprene jacket and a slightly heavier underlayer. I cannot do any kind of physical exertion in a giant puffy jacket because of overheating. If you are wearing a thick jacket that is causing too much heat to build up, it is much better to take the jacket off and carry it until it is needed rather than continue to sweat under it. When you are adding wind chill as when biking or skiing or on a windy day, the most important thing is to have a layer that will completely block the wind from taking body heat away from you.

Taking it off: It’s interesting that the thing to be most aware of in the cold is the increase of your core body temperature. I have found that it is best to wear clothing that you can easily remove or open to monitor heat. I pay close attention to my body heat to avoid sweating (NEVER sweat in the cold). This may mean annoying repeated opening and closing of clothing articles, but keeping a stable temperature for your body is a primary responsibility of the operator. I have gloves that have finger and thumb covers that open up and I am constantly monitoring body heat by opening and closing the gloves-your hands release a lot of body heat. Your outer layer(s) should have zipper or snap openings so that you can easily open and close them as needed. A few minutes of heat release makes a huge difference. You lose a lot of heat through your neck and head so having a covering that can easily be removed or adjusted is critical. I use a thermal headband that will protect my ears and prevent too much heat loss, but that can also be moved down to my neck if I need to release heat. I love neoprene leg and arm warmers that can really hold in heat when needed but can also be rolled off if you need to release heat. I am especially aware of the parts of the body that allow heat loss because I had a great student in the past who was missing the lower parts of her arms and had a difficult time with overheating because she was missing all of that arm and hand skin area normally available to allow the body to cool itself. This is why being able to expose your hands, arms and legs to dump heat is critical and vests or arm/leg warmers do that well. It is also very important that you keep your hands and feet warm. Your body will begin to restrict blood-flow to your extremities if it senses that your core temperature is getting too low and your hands and feet will be the first to experience this. Make sure you have well-insulated boots and good thick moisture-wicking socks. Wool is great for this purpose and will be able to maintain a decent amount of heat around your feet and toes. I already mentioned the gloves I like that allow me to cover and uncover my fingers to release heat, but of course you are not going to take boots on an off so a good insulated boot is critical.

It funny that as I was writing this, there was an ad on TV with a super buff tough guy trying to sell a “microfleece tactical hoodie…” blah blah. I have found that hoodies are really bad for being out exerting yourself because there is no escape from the built-up heat. No zipper to open, no way to free your arms no way to use it to control body temperature. Sure, its great for sitting around drinking a beer around a campfire, but be careful of hoodies or slip-over sweaters when exercising. An interesting side note is that while we see actors doing winter scenes in thick coats or commercials showing happy families playing in the snow in adorable parkas, encouraging us to purchase these things, in reality, they need special accommodations on the set to be able to wear these jackets and not overheat during a shoot! I found out that actors often wear special cooling vests under the jackets, have refrigerated furniture/props to cool themselves or have fans blown on them during breaks in order to not overheat. Don’t believe the hype. Learn how your own body operates and act accordingly. Just make sure that you are also prepared to stay warm if you are incapacitated by an injury and can’t continue to produce the body heat you were previously trying to shed. This is where the DON’T ALLOW YOURSELF TO GET SWEATY part becomes especially important. You will quickly reach hypothermia if you are in wet clothing and are unable to produce body heat through exertion. Dry clothing is much more able to contain body heat. I have learned from experience that I can comfortably shovel snow in freezing weather wearing just a long-sleeved T-shirt and good gloves -anything thicker just makes me overheat in minutes and involves a wardrobe change.

Feed the furnace: My advice on keeping warm and toasty while out adventuring is to monitor clothing, keep the furnaces burning by staying active and feed the fire with added calories. Snacking on higher calorie foods when operating in cold weather will allow your body to continue to keep producing that body heat that is keeping you alive. We operate on a narrow knife edge of acceptable body temperature. Like Goldilocks found out, too hot (100 and higher) isn’t good (hyperthermia), too cold (96 and lower) isn’t good (hypothermia) and just right (97-99) is hard to maintain when you are out in the cold producing excess body heat.

As I move along, I constantly stay aware of my internal body temperature and keep it stable by opening and closing whatever clothing is appropriate. It takes longer to build heat than release it so being aware of the trends in your body’s heating and cooling is a critical responsibility. If you are climbing a hill and will soon be descending, it’s fine to store up some extra heat, but if you are already hot before you start climbing, you might want to open things up in preparation for climbing body temperatures. Have fun out there and stay cool in the cold.