Everyone has heard that you should dress in layers, but it can often be confusing as to what that exactly means. Which layers? What order? Multiple layers of the same thing, or different things?
It is important to think of your layers in any season. Depending upon the season you might need to consider managing your body heat, sun protection, insect protection, the chance of rain, or sub-freezing temperatures. In any season, exposure or hypothermia can be a risk to the unwary and unprepared. Changes is weather or elevation can quickly change the temperatures within a single day.
However, remembering the four words above – WICK, WARM, WATER, WIND can get anyone off to a great start using layering in order to better enjoy the outdoors. When it comes to layering, you aren’t going to necessarily need each of the four layers every outing, but if you think about each of these layers before you go outside, it will help you to make an informed decision about the layers to choose. Often having a layer option from each of the above available to you can give you the flexibility to have the right clothing for the weather.
I know from being outdoors with my kids, and also from my own experience, that the outdoors is a far more enjoyable experience when you are comfortable. If I want myself and others to be outdoors more, we can stay out longer and have more fun when everyone is comfortable. That requires thinking about layers.
Just the other day, we stopped for an impromptu hike on a segment of the Ice Age Trail. Despite the fact that the sun was out and the thermometer said 38 degrees (making for a pretty nice January day in Wisconsin) ,the wind was gusty, and not having planned to be hiking we were not prepared with our layers. While we still tried to hike, we didn’t get more than a mile along the trail when we decided to turn back to the car. With better preparation, we would have been able to stay on the trail longer.
WICK
In many ways, the most important layer is a wicking layer close to your body. Humans have the incredible adaptation of sweating to cool our bodies, but this same cooling adaptation can work too well, even leading to hypothermia. Therefore, a layer of material that draws perspiration away from our skin gives us more control over this adaptation. In the heat, the wicking layer can be left exposed and the perspiration permitted to evaporate off of this base layer to cool your body. In the cold, the wicking layer draws the perspiration away from your skin into a subsequent layer. By drawing the perspiration away from your body, evaporative cooling is controlled or minimized. Our bodies are so well adapted that they will effectively perspire, but it is the controlling of where and when the perspiration evaporates that provides the benefit in the outdoors.
Typically, wicking layers are synthetic materials like polyester or nylon, although natural fibers like silk can be used too. Wool works differently and will be discussed later. Most importantly when looking for a wicking layer, cotton should be avoided. When cotton becomes wet the cotton fibers aborb the water, soaking the cotton and retaining the water close to the skin. However, wicking fibers (like nylon, polyester, and silk) repel water and the water is transferred away from the body through the fabric to the outer surface.
WARM
The most effective way to control your perspiration is to control your body heat in the first place. This is where your warm layer or layers come in. There are many insulating fabrics and clothing articles available, but in general you are looking for something that will trap air close to your body, your body heat warms this layer of air, which in turn, keeps you warm. I’m going to focus on two natural insulators: down and wool.
Down are the insulating feathers of fowl, usually a goose or a duck. These feathers take up a lot of space relative to their size and weight, making them light weight. The structure of the feathers also keeps them from lying flat, providing lots of space to trap warm air. Therefore, down is a favorite insulating material. However, when down gets wet, the feathers can compact and severely limit the insulating effect. Therefore, it can be important to keep you “water” layer in mind when using down. There are now chemical treatments available that make down water resistant. Looking for down with a hydrophobic coating could provide you with a layer that will keep you warm in a wider variety of conditions.
What about wool? Often people use or consider wool as a base layer, however, while wool performs a wicking action that I’ll explain, wool is better thought of as an insulator that continues to perform while wet. Wool fibers can absorb a lot of water, however wool fibers are shaped differently than cotton fibers and therefore the two materials respond to moisture differently. Wool fibers are kinked and maintain these kinks even when the fibers are wet. These kinks maintain the air pockets that we need for warmth. Cotton fibers on the other hand are straight, but twisted, as the cotton fibers absorb water and expand, the fibers expand into each other squeezing out any air and making a poor insulator. I also mentioned that wool does perform some of a wicking action. Since wool can absorb a lot of water relative to its weight, the wool cloth will seek to create a moisture equilibrium within the material and disperse, or wick, the moisture away from the source (e.g. you body) to the dryer regions (away from your body. Therefore because of wool’s wicking and insulating properties, wool is a great material for your outdoor adventures.
WATER
Water can impair the insulating effects of our warm layers and evaporate, cooling our bodies. Our body’s perspiration is only one source of moisture, nature itself can provide the moisture in the form of precipitation, spray from a river or waterfall, or a heavy dew on the brush. A water-resistant or water-repellent outer layer can help to keep our other layers functioning properly. However, not all water layers are the same and therefore some consideration of your environment and use will be necessary. While a truly water impermeable material, like PE or PVC will keep water out, it will also keep water in. Remember “wicking” above? Without somewhere for your body’s moisture to go you may keep the rain out, but you will be swimming in sweat and wet just the same. On the other hand, a water resistant material may do a better job of “breathing” or letting your body moisture out, but will eventually wet out and be overcome by moisture in a heavy or persistent rain. Sometimes, when available, seeking shelter from a persistent or heavy rainstorm can be the best course of action.
WIND
Lastly, wind. When we are trying to stay warm, wind is our enemy. Wind exposes any weaknesses that we have in our other layers. The blowing wind can evaporate any moisture that our WICK layer left close to our body, cooling us by evaporative cooling. The wind can blow through our WARM layer disrupting those air pockets that make the WARM layer work. The wind can increase the force behind rain dropplets driving them between the fibers of our water-resistant WATER layer, causing the layer to wet out sooner. Lastly, the wind itself can cool any exposed skin by convective cooling further reducing our body temperature. Therefore in many ways, wind is the multiplier of any other weather and our lack of preparedness. Without keeping in mind a layer that will resist the wind, or mitigate the effects of the wind to our other well-planned layers, an otherwise pleasant day can be ruined, and unexpected bad weather can turn dangerous. Had we better considered the wind, our recent Ice Age Trail hike would have been longer and more enjoyable.
Hopefully, your next outdoor adventure will be a little bit longer and a little bit more enjoyable because you were better prepared with the right layers for the job.