Thursday, January 24, 2013
Hypothermia and Dressing for Winter
A little while ago I did a post on winter weather and a few people commented that there wasn't much information on clothing. Most people who live in cold weather areas already understand how to stay warm, and what clothing they need. As a result, many of us who live in these areas don't really think much on the clothing we wear. However for someone who normally lives in warmer areas of the country, this isn't something they are normally faced with, and some people may not know how to deal with clothing in cold weather.
The whole purpose of clothing in regards to cold weather, is to help protect our bodies and create a microclimate around our bodies to keep us warm. A regular human without the correct clothing can easily get hypothermia in cold weather, as well as other cold related injuries along with it. The normal human body temperature is right around 98F. Of course this has a small range that it can swing through depending on the person. Hypothermia however, is when the body temperature has dropped below 95F.
There are four different classifications for hypothermia. Mild hypothermia is when the human body's temperature has dropped somewhere between 95F and 90F. Moderate is 90F to 82F. Severe is 82F to 68F. The final classification is profound which is anything less than 68F. The lowest recorded temperature that anyone has recovered from, was in an near drowning case of a seven year old girl in Sweden, who's body temperature dropped to 55.4F.
Now people do not normally have thermometers with them, so it is important to know the signs of hypothermia so that you can determine if it is occuring, both for yourself and for other people.
Mild hypothermia is going to be the hardest to diagnose because it is not very easy to recognize. The symptom that most people would be able to recognize would be shivering, which is the body's response to try and preserve heat. Other symptoms that could be happening, but would be hard to diagnose are increased urination, mental confusion and even some liver damage.
Once hypothermia reaches the moderate stage it becomes much more noticable. A person will start having trouble moving. Coordination will start to deteriorate, and the person may start to stumble. The person may also start get confused. Once hypothermia reaches the moderate stage, the physical symptoms also become more obvious. Shivering becomes more violent, and skin becomes pale. Extremities like ears, fingers, toes and even lips can start to turn blue.
As hypothermia reaches the severe stage a persons mental faculties will continue to deteriorate with speaking becoming difficult. The person will have trouble thinking, and may have trouble remembering things. The person will also likely exhibit irrational behavior. Stumbling is very likely at this point and walking will become almost impossible. Exposed skin will be blue and puffy at this point.
At the severe stage of hypothermia there is also quite a bit starting to go with the bodies systems. Heart rate, breathing and blood pressure will all decrease. Major organs can start to fail at this point and clinical death can occur. However, brain death will actually take longer at this stage because of decreased cellular activity.
One thing that should be noted is that once a person reaches moderate to severe hypothermia, and they start to exhibit confusion and irrational behavior, there is something known as paraoxical undressing that can occur. The hypothalamus regulates body temperature. During moderate to severe hypothermiathis area of the brain can malfunction, or blood vessels can become exhausted and relax, leading to a surge of blood. With either of these occurances, the result is the same, and a person will start to feel overheated. Twenty to fifty percent of hypothermia deaths are associated with this occurance.
Now, knowing what hypothermia is, we should look at ways to prevent it. The first is by simply being prepared. Check the weather, know what the temperature is outside and dress accordingly. Knowing the temperature is important, and will help you be prepared better than just knowing that it is cold outside. Cold can range anywhere from 40F to -40F, and the clothing you need at each of those temperatures will be different. More clothing will be needed at -40F, and too much clothing at 40F can lead to sweating, which in turn could itself result in hypothermia.
There are a few different things you can do to get the maximum use out of your winter clothing. When you dressing for cold weather, you always want to make sure you dress in layers. Layering helps regulate temperature and if you do it correctly it will help keep you from getting cold, or alternatively from getting too warm as well.
When you are layering, you want at least three different layers. You want to start with a base layer. What kind of base layer you want is dependent on what kinds of things you will being doing outside. If you are planning on doing a lot of activity you will want to have a lighter base layer with wicking fabric to help keep you dry. You will here many survivalists say, "If you sweat, you die" and cold weather is exactly the reason for this. Therefore staying dry is something that should be considered when dressing for cold weather.
The middle layer of clothing is perhaps one of your most important layers because it acts as your insulation. Heat from your body will get trapped between your base layer and the mid layer, as well as between the mid layer and the outer layer. This gives you two spaces of warm air which will create a microclimate that is much warmer than then the rest of the air outside. Good options for this layer are fleeces, down sweathers, or a synthetic jacket with insulating properties.
The outer layer is less for keeping warm, and more for keeping out the elements that will make you cold. You shouldn't need an excessively bulky outer layer because your mid layer should be providing a good amount of insulation. You want your outer layer to be able to shed rain or snow, but still be be breathable so you don't sweat. Have wind breaking properties is also a good option to have on outwear as well, to stop wind from cutting through your layers and cooling off those insulating layers.
In addition to your layers there are some other accessories that are a good idea to have. Hats are very important because you loose a large amount of body heat through your head. Gloves are also important because when you get cold your body will direct blood flow away from your skin and extremities to try and maintain your core temperature.
Good shoes and socks are another thing to make sure you have. You want to make sure you have well fitting shoes that aren't too tight, and arn't tied too tight. If your shoes are too tight it will restrict the blood getting to your feet and that can lead to even well insulated feet getting cold. Having good socks are also important. If you are going to be active midweight socks with wicking properties are a good choice. Wool and wool blend socks are also a very good choice for socks because the material insulates very well, even when wet.
A final thing to consider for winter weather is the sun. It seems strange to worry about sun issues during the winter, but it is just as important as keeping warm. Some people, especially those that are fair skinned, should consider sunscreen. You can get sunburnt just as easily in winter as in the summer. Sometimes even more so, because of sunlight reflecting off of snow on the ground. Sunglasses are also a good thing to have, to help protect your eyes from snow blindness.
So take a look at your clothing, and make sure you have everything prepared ahead of time. Be prepared for regular life as well as survival situations. That way you can enjoy your days out in the winter weather.