Hypothermia

At this time of year as the weather becomes warmer during the day people tend to get careless about staying dry as well as keeping their clothes from getting wet. The warmer weather feels great and it seems warmer than it is because we have become acclimated to the colder temperatures. This can make for a dangerous situation. In many areas during spring there can be huge temperature swings between day and night. You could have temperatures in the 80’s during the day and then they can dip below freezing at night. This could be a deadly combination if you find yourself wet and cold.

WIKIPEDIA Definition and Effects of Hypothermia

 
Hypothermia (from Greek ὑποθερμία) is a condition in which the body’s core temperature drops below that required for normal metabolism and body functions. This is generally considered to be 35.0 °C (95.0 °F). Body temperature is usually maintained near a constant level of 36.5–37.5 °C (97.7–99.5 °F) through biologic homeostasis or thermoregulation. If a person is exposed to cold, and their internal mechanisms cannot replenish the heat that is being lost, the body’s core temperature falls, and characteristic symptoms occur such as shivering and mental confusion.
One of the lowest documented body temperatures from which anyone has recovered was 13.0 °C (55.4 °F) in a near-drowning incident involving a 7-year-old girl in Sweden in December 2010.[1] Hypothermia is the opposite of hyperthermia which is present in heat exhaustion and heat stroke.

 

Mild

 
Symptoms of mild hypothermia may be vague, with sympathetic nervous system excitation (shivering, hypertension, tachycardia, tachypnea, and vasoconstriction). These are all physiological responses to preserve heat. Cold diuresis, mental confusion, and hepatic dysfunction may also be present. Hyperglycemia may be present, as glucose consumption by cells and insulin secretion both decrease, and tissue sensitivity to insulin may be blunted. Sympathetic activation also releases glucose from the liver. In many cases, however, especially in alcoholic patients, hypoglycemia appears to be a more common presentation. Hypoglycemia is also found in many hypothermic patients, because hypothermia may be a result of hypoglycemia.

 

Moderate

 
Low body temperature results in shivering becoming more violent. Muscle mis-coordination becomes apparent. Movements are slow and labored, accompanied by a stumbling pace and mild confusion, although the person may appear alert. Surface blood vessels contract further as the body focuses its remaining resources on keeping the vital organs warm. The subject becomes pale. Lips, ears, fingers and toes may become blue.

 

Severe

 
As the temperature decreases, further physiological systems falter and heart rate, respiratory rate, and blood pressure all decrease. This results in an expected heart rate in the 30s at a temperature of 28 °C (82 °F).
Difficulty in speaking, sluggish thinking, and amnesia start to appear; inability to use hands and stumbling is also usually present. Cellular metabolic processes shut down. Below 30 °C (86 °F), the exposed skin becomes blue and puffy, muscle coordination becomes very poor, walking becomes almost impossible, and the person exhibits incoherent/irrational behavior including terminal burrowing (see below) or even a stupor. Pulse and respiration rates decrease significantly, but fast heart rates (ventricular tachycardia, atrial fibrillation) can occur. Major organs fail. Clinical death occurs.

 

Paradoxical undressing

 
Twenty to fifty percent of hypothermia deaths are associated with paradoxical undressing. This typically occurs during moderate to severe hypothermia, as the person becomes disoriented, confused, and combative. They may begin discarding their clothing, which, in turn, increases the rate of heat loss.

 
Rescuers who are trained in mountain survival techniques are taught to expect this; however, some may assume incorrectly that urban victims of hypothermia have been subjected to a sexual assault.

 
One explanation for the effect is a cold-induced malfunction of the hypothalamus, the part of the brain that regulates body temperature. Another explanation is that the muscles contracting peripheral blood vessels become exhausted (known as a loss of vasomotor tone) and relax, leading to a sudden surge of blood (and heat) to the extremities, fooling the person into feeling overheated.

 

Terminal burrowing

 
An apparent self-protective behavior known as terminal burrowing, or hide-and-die syndrome, occurs in the final stages of hypothermia. The afflicted will enter small, enclosed spaces, such as underneath beds or behind wardrobes. It is often associated with paradoxical undressing. Researchers in Germany claim this is “obviously an autonomous process of the brain stem, which is triggered in the final state of hypothermia and produces a primitive and burrowing-like behavior of protection, as seen in hibernating animals.”This happens mostly in cases where temperature drops slowly.

 

 

It is important to dress in layers just like you would during the winter months. As you become warm remove a layer at a time until you are not perspiring. Try to keep your clothing as dry as possible. If you find yourself crossing a river or stream, try to cross at a shallow point or carry clothing across if possible. If clothing becomes wet either because of the environment or because of perspiration, try to get the wet clothing dry before dark when temperatures start to drop. Dry clothes over a fire or try to get them dry by laying them on large warm rocks in the sunlight of the day. Whatever you must do to get dry and warm before dark do it.

 
It is important to carry rain gear and a good waterproof shelter at this time of year as well. A day of hiking in a cold drenching rain can sap you of energy and drop your core temperature quickly once you stop moving. The last thing you want to do is to have a poor shelter that is not waterproof and find yourself in a freezing rain storm in the middle of the night. It’s all about being smart and preparing ahead of time. Be prepared for the changes of temperature and weather that go along with this time of year. The better you are prepared, the better the chance that you will enjoy your trip and return safely. Be wise about the clothing you are wearing and the materials they are made out of. Know and learn the limitations of all your gear. Enjoy your spring hiking and camping! Take in the fresh air and new life that is coming forth. This is such a wonderful time of year to be out on the trail enjoying nature. What special gear is a must have for you at this time of year? What special trip do you have planned for this spring? (Please share photos of your trip)