Heat or cold, what is more dangerous for the body?
Some can not stand the heat, some cold, but you never asked this question - which of them is more dangerous? It would seem from the heat recovery is not, from the cold even if you can bundle up and get warm. But in fact, everything is completely different ...
Scientists on this issue give a definite answer - the greatest harm entails being in extreme cold than in the heat. Death from extreme cold comes in 17 times more than from the intense heat. Specialists have found that the cause of death in 0, 86% of people are sharp temperature changes.
As death occurs from hypothermia
So, you end up in the cold conditions, with no hope of escape, and keep warm. What will happen to you.
36.6 - 35 degrees
When the body temperature reaches 36 degrees, the muscles around your neck and shoulders will start to shrink - this is called preconvulsive muscular tone. The receptors send a signal to the hypothalamus, which in turn, gives the command to narrow the entire network of capillaries on your body surface area and, therefore, the arms and legs begin to ache from the cold. Approximately 45 minutes later the body temperature drops to 35 degrees - the body begins to shake due to the natural reaction of the muscles that rapid compressing and unclamping impart body heat.
35 - 32 degrees
With each degree to which the body temperature is lowered after 35, the level of metabolism in the body decreases by 3-5%, and then 34 degrees a person loses his memory and mind - you have ceased to understand where you are and what you are doing. Most often it is at this moment a man falls into the snow and freezes frantically. Below 33 degrees occurs apathy, and below 32 - stupor. 32 - 30.5 degrees
This area of extreme supercooling in which the body attempts to warm ends themselves tremor. Blood clots occur, the drop in oxygen consumption. Constricted blood vessels of extremities squeeze a huge amount of liquid with which the kidneys are struggling to cope. At this point, a person ceases to learn everything around him - between 31 and 30 degrees, he does not even know his native person.
30.5 - 29.5 degrees
In this state, the electrical impulses that send chilled nerve endings in your heart become arrhythmia, the heart pumps just 2/3 of the total volume, and the lack of oxygen causes hallucinations. Death occurs about 29, 5 degrees.
At extremely low temperatures, the human body as it is preserved, greatly slowing the internal processes. Many people found supercooled seem dead only at first glance. The body can exist in such a state for hours and bring it out of him is very carefully and gradually.
An interesting point - in a painful attack, at body temperature 30-29, 5 degrees occurs a phenomenon called "paradoxical undressing." Very often, criminologists, finding stripped body frozen man think that he was robbed and left without the clothes. In fact, during this peak people will tear their clothes. The exact explanation for this phenomenon is not present, but the most logical explanation is that as the body of the cooling body includes a protective function - vasoconstriction, which occurs as a result of the involuntary contraction of the blood vessels outside of the skin integument, which allows to reduce heat loss. However, the required energy and glucose consumption for compression of these muscle cells, however upon further cooling compressing vessels at some point muscle relax. This causes the warm blood, bathing the internal organs, pour the peripheral tissues, and the person feels "hot flash" - a powerful burst of heat. Without giving a report that makes a man frantically rips off his clothes, what aggravates their situation.
However paradoxical undressing is not the only thing that happens to dying from hypothermia. Parts of the body of people who died from hypothermia, have wounds, scratches, abrasions on the hands, knees and elbows, and the bodies themselves are in "position, which indicates the desperate attempts to protect - for example, under the bed, behind the cupboard, in a recess." Scientists is explained by the behavior of the animals that before hibernate, digging pits. So man, supercooled, prevents heat loss and burrows as deep as possible - in the ground, under the branches, in the leaves, etc. This phenomenon is called "terminal digging"...
Another fact about cold
It is believed that the cold air is extremely harmful to health, but in fact this is not true. Of course, it all depends on how much you are in the cold and under what conditions, but due to the fact that the winter air contains 30% more oxygen, it has a positive effect on the human skin. Moreover, the cold air is able to alleviate the condition of patients with bronchitis and even pneumonia - but only if the cold dry, that is, the street is not damp.
Also, the frosty air helps people who suffer from cardiovascular disease and helps to stop migraine attacks.
Did you know that there is a physiological adaptation to the cold?
In some people, constantly living in cold climates, such as the Chukchi and Eskimos, metabolism by 25-50% harder than the inhabitants of the temperate zone.
Australian Aborigines and Tibetan monks can spend the whole night almost naked with an air temperature around zero and it does not even feel a shiver. Korean and Japanese women pearl divers, providing for several hours a day in water at a temperature only about + 10 ° C is also not sensitive to cold.
As a death occurs in the heat
The body temperature exceeding 43 ° C, is lethal to humans. Changes in properties of proteins and irreversible cell damage starts already at 41 ° C, while temperatures above 50 ° C for several minutes causes the death of all cells.
Thermal shock occurs when the internal temperature crosses the border 41 ° C and thermoregulation system of the organism is disrupted. The first warning signs - flushed face, hot dry skin, headache, dizziness, fatigue and irritability. Next comes the confusion and loss of coordination.
With a further increase in body temperature above 42 degrees, a person dies from a brain injury. It is our brain - internal thermostat and normal human hypothalamic thermostat is set at 37 ° C, but at a fever, he can switch to 2-3 degrees above the temperature and the same sensitivity is adjusted according to the new mark. Signals from the heat and cold cause local skin reaction sensors sending signals to the brain, where, based on information that is associated with the data central thermoreceptors in the hypothalamus, adjusts the overall heat loss and heat production of the organism. The skin surface is cooled to temperatures significantly below ambient air due to sweating, which controls the hormone adrenaline released into the blood by increasing body temperature.
In humans, there are about 3 million sweat glands, which play a major role in thermoregulation. The human skin takes the heat that is produced by muscles and internal organs, and gives it to the environment. At higher ambient temperature vessels dilate, increasing the heat transfer, which takes place in four stages - radiation, conduction, convection, and sweating.
When a significant increase in outside temperature increases body perspiration - then cooling the skin (1 ml by evaporation of sweat from the skin surface of the body spends about 2400 calories), which, in turn, cools extending adjacent blood vessels.
Sweating may increase heat transfer to about 20 times, but this is accompanied by a significant loss of liquid (about 3 l / h). Of course, such intensive sweating may not last long, so the person who is in the heat loses per day about 10-12 liters of water, which goes along with the body and necessary for the functioning of the salt, the lack of which leads to painful spasms of the limbs. Man stops moving. With prolonged exposure to high temperatures there is a failure of adaptive mechanisms, there is a so-called heat shock, and the person starts to experience nausea, dizziness or weakness (or all at once). Before the eyes float dark spots that hinder visibility, can occur muscle spasm or swelling of the legs.
If the body will continue to be subjected to temperature extremes, eventually there is a risk of terminal organ damage - the state, when they are almost "cooked". From this point, the person is at risk of permanent disability or even death.
Why are people being in the sauna, do not die at high temperatures?
Most people are hard to endure a temperature of 50 ° C with high humidity, but in a dry 90-degree heat to man for some time quite comfortably. It saves all the same sweat. Dry air temperatures up to 127 ° C (e.g. in a sauna) can withstand up to 20 minutes, and for some even this is not a limit. The temperature in the bath is always lower than in the sauna, although both are perceived equally hot. However, this endurance is not infinite. Brain cells are extremely sensitive to heat, their limit of - 42 ° C, so the increase in body temperature only a few degrees has a great influence on the brain.