Published on December 6th, 2013 | by Pat0
How to Recognize, Treat, and Prevent Hypothermia
As much as we all would like to believe our physical exertion and stamina out on the trail would make us immune to something like hypothermia, the fact remains that for cold-weather hikers, it will always be a threat and something worth full consideration when prepping for a hike.
In fact, hypothermia is not just a concern during extreme conditions. Many fatal cases of hypothermia occur even in 40-50 degree weather (source: Hiking & Backpacking: Essential Skills, Equipment, and Safety).
As winter sets in, here are the facts surrounding hypothermia, as well as tips for how to recognize and treat it while out on the trail:
What is hypothermia?
Hypothermia is a set of symptoms caused by a significant and sustained drop in core body temperature. A healthy core body temperature ranges between 98-100 degrees Fahrenheit. A hypothermic body temperature, on the other hand, is categorized as anything at or below 95 degrees Fahrenheit. While degrees of hypothermia exist on a spectrum, from mild to profound, anything at or below 80 degrees Fahrenheit is considered severe and urgently life-threatening. That said, even a mild case of hypothermia is cause for concern and should be addressed immediately.
The most severe reported case of hypothermia, from which the subject has survived, involved a seven-year-old girl living in Sweden, whose body temperature dropped to a staggering 55 degrees Fahrenheit during a near-drowning accident (source: Radio Sweden).
The causes for hypothermia are wide-ranging in context, but physically speaking it’s fairly simple: your body is losing heat faster than it is able to regenerate heat. This most commonly occurs when a person is exposed to low temperatures for a prolonged period, but is easily made worse when a person is wet (caused by precipitation, sweating, or otherwise) and/or has consumed alcohol, as both of these conditions not only mask our perceived body temperature (we think we’re warmer than we actually are) but also cause our body to dehydrate and release even more heat more quickly.
The symptoms of hypothermia vary depending on the severity, but the first visible signs of hypothermia are usually shivering, numbness, drowsiness, and marked muscular weakness. Even with a mild case, an increase in heart-rate (tachycardia), shortness of breath (tachypnea), vein constriction also occur.
As severity increases, more symptoms manifest. Blood sugar levels can begin to drop, which — combined with numbness and increased heart-rate — graduates muscular weakness to muscular coordination failure. Extremities will continue to experience blood vessel constriction and increased numbness, in an effort to preserve more internal, vital organs. Slurred speech becomes a symptom and, when severe enough, mental confusion and disorientation will occur.
Eventually, as the body’s core temperature continues to drop, heart-rate and respiration will begin to decrease, as the muscles in those organs begin to shut down. In the most severe cases, mental faculties shut down, as well, causing sluggish thinking and amnesia. At temperatures below 86 degrees Fahrenheit, the skin will also swell and turn blue, and walking becomes almost impossible.
At severe and even moderate stage, phenomena known as “paradoxical undressing” and “terminal burrowing” have been observed. Paradoxical undressing occurs when, as disorientation sets in, the subject begins discarding their clothing, causing further heat loss. One theory suggests that the muscles controlling the blood vessels in the extremities are exhausted, causing relaxation and increased blood flow to those vessels. The subject therefore feels warm, and removes their clothing (source: Forensic Pathology of Trauma).
Terminal burrowing, thought to be in line with other survival instincts, occurs when the subject crawls into a confined space during hypothermia-induced disorientation.
Fortunately, hypothermia is easy to combat if recognized early. Generally, when treating hypothermia, focus on rewarming, rehydrating, and replenishing sugars in the body (all vital elements of our body chemistry lost during prolonged exposure to the cold).
If you experience any of the symptoms mentioned above, drop everything and make yourself warm. If possible, strip yourself of your wet clothes and put on dry ones (why it’s always a good idea to pack extra clothes on a cold-weather hike).
If you have one, crawl into your sleeping bag and, if possible, heat up something warm to drink (tea, soup, hot chocolate, even hot water). Another good trick for re-warming foods is hot Jell-O, in that it will also replenish the sugars the body loses when hypothermic.
If you are traveling in a group, there’s no understating the value of sharing body heat.
There’s also no secret to preventing hypothermia beyond layering of clothing and keeping dry whenever possible. This can be tricky while out on the trail, since physical exertion of any kind will cause you to sweat. Do not be fooled as you become hot during your hike: that’s not your core temperature increasing… it’s the clothing you’re wearing keeping your body heat at the surface, making you feel warmer than you actually are.
Wherever the trail takes you this winter, have fun but be prepared!