A Backpacker?s Guide to Making Every Ounce Count: Tips and Tricks for Every Hike (2015)
When we discussed protection from the elements in Chapter Three, we focused on the shelter when you are asleep. Proper protection from the elements, when hiking or simply hanging out at the campsite, is just as important. When it comes to staying warm with the clothes on your back, you need to be aware of the different types of fabric that are out there.
Two terms are very important when protecting yourself from the elements while backpacking: hypothermia and hyperthermia.
Hypothermia is when your core temperature drops below 35.0°C (95.0°F), the temperature for normal metabolism and body function.
Hyperthermia is when the body takes in more heat than it releases.
You can see that regulating your body’s core temperature is very important while backpacking. You can’t just say you’re too cold and run inside to get warm. You need to know how to regulate your temperature with the clothes you have so you don’t get too warm or too cold. Getting too warm is also a concern because you may begin to sweat profusely.
To regulate your body’s temperature, you need to adjust the layers you are wearing. But what type of clothing should you get?
The bottom line is this: Stay away from cotton when backpacking, especially in the cooler months. The phrase we use is Cotton Kills, and here is why: Cotton holds water more than your synthetic materials such as polyester and nylon. So when cotton is wet, it loses its insulating value, unlike wool, which will retain its insulating value even when wet. So if you must wear natural material, give wool a shot.
When water evaporates, the surface that holds the water cools down. So if you have on cotton while hiking, and you get wet, you will need to dry that article of clothing as soon as possible. Your clothes protect you from the elements, so if you are in wet clothes, you will cool off faster and could slip into hypothermia.
Normal human body temperature in adults is 34.4-37.8°C (94-100°F).
Sometimes a narrower range is stated, such as 36.5-37.5°C (98-100°F).
Hypothermia is defined as any body temperature below 35.0°C (95.0°F).
Hypothermia is subdivided into four different levels:
✵ Mild: 90-95°F (32-35°C)
✵ Moderate: 82-90°F (28-32°C)
✵ Severe: 68-82°F (20-28°C)
✵ Profound: less than 68°F (20°C)
Therefore, you can see that if you wear cotton, you will be colder. Not only when, or if, you fall into the creek and get wet, but when you sweat while hiking, working at camp, gathering wood, and so on. Your best bet is to wear synthetic material.
You will not find any cotton in my pack other than a few bandanas. I stick to the synthetics unless it is my down vest, coat, and sleeping bag.
On the other hand, while hiking in the warmer months, wearing a cotton shirt may prove to be a good idea since you can wet the shirt, put it on, and it will be like standing in front of an air conditioner vent.
We were camping in June one time, and I was so hot I soaked one of my polyester shirts in the creek, wrung out the excess water, and put it on. The relief was wonderful. I cooled down almost instantly—or at least it seemed that way at the time. A cotton shirt would have held the water and kept me cooler longer, but it may not have dried out in time before nightfall, and I could have been in trouble. The thing with cotton is that it takes a while to dry in less than optimal conditions.
In the bright sun, laid out on a rock or hanging on a fence post, sure it may have dried faster. But we were in the woods, in the shade, with a light breeze blowing, so the cotton shirt would have taken too long to dry.
Let’s look at the four ways we lose body heat:
The most common form of heat loss with clothing is convection. This happens when air (or water) touches and moves away from the skin carrying heat with it. This type of heat loss accounts for the highest percentage of the body’s heat loss under normal conditions.
When you sweat, you produce moisture on your skin. When your sweat evaporates, the moisture turns into vapor. When this happens, the vapor removes heat from your body.
This type of heat loss only has a minor effect. In conductive heat loss, heat is passed directly through a stationary medium that has a lower temperature.
This type of heat loss only occurs to solid objects (like your body). The sun heats up your body through radiation. It doesn’t heat up the air directly.
Radiant heat loss from the human body is only minor except when all other channels of heat loss are covered. In hiking situations, radiant heat occurs not from the skin but from the fabric close to the skin.
Heat loss through this channel is prevented or reduced by reflective materials that turn the heat back to the body. This is not always ideal in a hiking situation.
Now, let’s talk layers: The only thing to remember about staying warm is to not get cold. Now before you say out loud “Duuh, that’s obvious,” let me explain.
Per the data above, you can slip into dangerous areas if you lose only a few degrees of warmth. Once you get so cold your body starts to shiver uncontrollably, you may have slipped too far to the other side. Once you get to the point when you can’t stop shivering, getting warm again might just prove to be a real challenge. To avoid this scenario, you will want to regulate your body’s core temperature with layers. Think of it like a thermostat in your home.
As stated before, I ran into this at Ice Water Spring shelter in the Smoky Mountains. I unzipped my bag too fast, and the cold air hit me hard. I could not stop shaking while answering nature’s call, and I knew I was in trouble. But luckily for me, and those around me, I was able to increase my temperature and pull out of the danger area.
If you slip into hypothermia, it is not only bad for you but for the rest of your group as well. If you get into this kind of trouble, the burden falls on other folks in your group to get you warm, or to safety, whichever the situation calls for.
This scenario is easily avoidable if you can figure out how to manage your core temperature using the clothes on your back and the clothes you carry with you.
Using layers is how you are able to control your body’s core temperature and not get too cold or too warm. There are three primary layers to know about:
✵ Base Layer
✵ Insulation Layer
✵ Shell Layer
Your base layer needs to have a level of insulation factor. For me, my top base layer is a Patagonia shirt, and it is almost too hot to wear while I am hiking. But at night, oh man, I love it. My bottom layer is REI brand and keeps me just as warm. Both are made from synthetic material. This is also crucial, so pay attention. The base layer needs to have a wicking property as well.
“Wicking” is the process whereby the fabric pulls moisture away from your skin allowing it to evaporate without affecting the temperature of your body and not allowing you to get cold due to the evaporation process. You still don’t want to depend on the base layer to remove all the sweat you produce because there are limits to everything. Once you understand all three of the basics, we will go over some scenarios where different applications of different layers will need to be understood.
This layer is just what it sounds like—to insulate you from the cold. It can be fleece, down, polyester, nylon, but never cotton. Cotton kills.
You may need multiple layers based on the weather conditions. If the temperature only drops to 30°F (-1.1°C), you may survive with only one layer of insulation. If the temperature is due to drop down to well below 0°F (-17.8°C), you may need to have multiple layers of insulation or even a layer of down. This is all up to you and your needs. In Georgia, where I do most of my backpacking, the coldest temperature I have been in was 5°F (-15°C), so I can limit my number of insulation layers.
Maybe I should also mention that I am the human furnace. My wife really loves me in the winter time. I actually start out on her side of the bed to warm it up for her, and it only takes me about five minutes. When she climbs in, her side is already warmed up, and she tells me that I am better than an electric blanket.
Some of the guys in the group were still cold in multiple layers, but I had on my base layer, one layer of insulation, and a down jacket, and all that while in my down sleeping bag, I was hot and had to strip down some of those layers. I also have the insulation of my underquilt under my hammock while I am sleeping.
The shell is a layer to protect you from the water and wind. When shopping for a shell, remember to keep it light, folks. After all you will be carrying this layer with you unless it is raining while on the trail. I don’t mind hiking in the rain, but I won’t start out in the rain, if I can avoid it. My shell is a light and thin raincoat with a hood and works great for me.
Your shell can be used in place of an insulation layer, if the weather is too warm for your actual insulation layer but too cold to walk around in just your base layer. The shell is also good for adding extra insulation on top of all your other layers when the temperature drops below the expected. Keeping the wind off of you will prevent one of the four ways of losing heat: convection.
Using your shell to help keep you warm is an option, so keep that in mind when purchasing it. I have worn my raincoat to keep me warm more often than to stay dry. For example, on one trip, I was too warm with my fleece on, so I stripped down to my top base layer and a shirt. I then got a little cold, so I added my shell, and I warmed up quite nicely.
Like with any other gear you have, make sure the gear you select is in working order. Test your base layer while at home by going outside for a while to see how your body reacts to just the base layer. Then add a layer of fleece or just your shell. Learn how your body reacts to each of the layers you will carry so you will know how it reacts on the trail. Test everything.