The optimal ambient temperature, in which a person is able to maintain body temperature outside a stressful situation, is from 26 to 30 degrees Celsius. According to statistics, people die in an emergency from hypothermia or overheating. These general terms refer to death from hypothermia or hyperthermia. Only hypothermia is considered below..
Hypothermia, signs and symptoms of hypothermia, factors affecting heat loss in cold conditions.
Hypothermia, the so-called lowering of the average human body temperature below 35 degrees. Controlled hypothermia is sometimes used in surgery to temporarily lower a patient’s metabolic rate. But if the average body temperature drops to 33 degrees Celsius or lower, then you are unlikely to be able to help yourself. To control its internal temperature, the body must be able to feel the difference in temperature with the environment and react accordingly. To do this, it is equipped with receptors located on the skin, in the spinal cord, muscles and in the brain, which promptly trigger physiological changes in order to quickly cope with the impact of negative external conditions on the body.
The development and course of hypothermia is influenced by many factors:
Age and gender.
Food quality and degree of exhaustion.
Exposure to nature and duration of exposure.
Wind, temperature and humidity.
Previous adaptation to the cold and so on.
Signs and symptoms of hypothermia.
|Early (from 35 to 36 C)||Lungs (from 34 to 35 C)||Heavy (from 33 to 34 C)||Deadly (below 33 C)|
If the average body temperature continues to fall, then the trembling will stop, breathing and pulse will disappear, the skin will turn blue. There is a high probability of death.
Regulation of average body temperature.
Regulation of the average body temperature is called thermoregulation and becomes possible when appropriate physiological reactions and reflexes are performed, such as:
Blood vessel enlargement.
Chills and trembling.
Temperature control in humans is a balance between heat production from metabolic processes such as digestion and heat loss from breathing, evaporation (sweating), radiation physics, convection, and conduction. In a cold environment, body heat is retained primarily due to the narrowing of blood vessels located near the surface of the body, leaving most of the blood (heat) in the central part of the body. This allows the body to use the skin and the underlying fat layer as an insulating material..
The only area of the skin that does not constrict blood flow and always maintains an approximately constant temperature, in spite of environmental conditions, is the scalp. This is one of the reasons why the head and neck very quickly lose and gain heat. That is why they need special protection from the negative effects of the environment. Trying to regulate the temperature, the body changes the force of blood flow to the skin. In cold weather, blood vessels significantly reduce blood flow to the skin from normal volume. When the temperature continues to drop, the blood vessels in the skin expand. And if the temperature continues to drop even lower, then they begin to contract and expand alternately, so that the body can make sure that the skin remains intact by the cold.
A clear result of these actions are red ears, nose, hands and other parts of the body protruding from the clothes. If the temperature outside continues to decrease, then the external blood vessels continue to narrow. The next reaction of the body to cold is uncontrolled frequent convulsive muscle contractions from 10 to 20 times per second, better known as tremors, can increase metabolism by almost five times. The energy required for trembling is taken from fats and simple sugars, is consumed very quickly and requires replenishment, for example in the form of food.
Jitter decreases when the level of carbon dioxide rises (a poorly ventilated room), when oxygen in the air becomes more discharged (at a high altitude) or after drinking alcohol, which also reduces the jitter reaction. That is why alcohol is not recommended in cold conditions. Expanding blood vessels on the surface of the body, it complicates and interferes with the natural processes of thermoregulation, hypothermia occurs faster. Narrowed blood vessels due to nicotine use, dehydration, or for other reasons will also not lead to anything good..
When the blood in the circulatory system loses water, it becomes thicker. Thick blood circulates more slowly and sways harder by the heart, which in turn impedes the body’s ability to give off excess or distribute the necessary heat. Despite the fact that dehydration launches the protective functions of the body, one of which reduces the amount of water loss through urine, the effect of cold weather, on the contrary, increases its production, the body seeks to get rid of excess fluid in order to reduce energy consumption for maintaining heat. The end result is that the body loses more water than usual.
(radiation), can lead to at least serious health problems, or as a maximum hypothermia and death.