To minus 40 degrees: What happens to the body in extreme cold?

Parts of America freeze, temperatures in the Midwest have fallen to minus 40 degrees. Who plans longer trips by car, should prepare for possible mishaps and wrap up blankets, warns the US health authority CDC. Doctors warn about life-threatening conditions.

How does the body react to extreme cold?

The most important organs are located in the middle of our body and in our heads - they need to be protected. When it gets cold, the body pulls the vessels together in arms and legs and throttles the blood circulation so that less cold blood flows into the middle of the body. The consequences are palpable: fingers, toes and ears cool down first, there is also the greatest risk that frostbite form.

In addition, the muscles begin to tremble to produce heat. Their metabolism also changes, that is, the chemical reactions in the muscle to release energy from sugar in the form of heat. In extreme cold, these processes are not enough, the body temperature drops.

How fast will temperatures of up to minus 40 degrees become dangerous?

Without adequate protection, the body temperature can drop dangerously after only 30 minutes, says an emergency physician in "Time" magazine. Even faster it can lead to frostbite of the skin. If wind and temperatures of less than minus 27 degrees hit one another - as is currently the case in the USA - skin can freeze within a few minutes, writes the US Mayo Clinic.

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The fact that actual and perceived temperatures often diverge due to the wind can be easily explained: the body continuously emits heat, which forms a few millimeters thick, insulating air layer. If the wind carries away this warm air, an important protective mechanism is missing.

What are the consequences of hypothermia?

The normal body temperature varies from person to person, but is usually around 37 degrees. If it sinks by half a degree, we begin to freeze. From 35 degrees Celsius is an emergency, from 30 degrees, it is life-threatening. If the body temperature falls below 26 degrees, there is no chance to survive. Mostly fail as a result of the cold heart and circulation.

A beginning, serious hypothermia is usually noticeable by chills, also decreases the concentration. Those affected sometimes speak indistinctly, feel dizzy, become apathetic and sleepy. This also makes subcooling so dangerous: Without help many are no longer able to assess the situation and get help.

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Anyone who encounters a hypothermic person, should choose the emergency call and then bring the person concerned to a windless place, possibly at room temperature. It is important to ensure that the affected person does not warm up too quickly, for example because they are near a radiator, a fire or a warm bath, warns the ASB.

The sudden heat can cause the body to reopen the blood vessels in the arms and legs too quickly and the cold blood flows into the middle of the body. There it can lead to a so-called "afterdrop", an additional cooling. Rubbing and massaging are also counterproductive for this reason.

What happens with frostbite?

The signs of an incipient frostbite know most: The skin is cold and red, it tingles, eventually it can also become numb. At this stage, no permanent damage threatens. Penetrates the cold further into the tissue and freezes the skin, it turns yellowish-white and finally white-gray. It will first wax and finally hard. At the same time, all sensations of coldness and pain are lost.

If the cold has destroyed tissue, large bubbles form within 24 to 48 hours after heating, only then do the skin areas turn black. In first aid, it is important for frostbite, to avoid further cold and warmed up the places carefully, cold fingers in the armpit.

How can you protect yourself from extreme cold?

One of the most important advice: do not drink alcohol. It increases the heat loss as it expands the blood vessels. He also makes sure that we feel the cold less. However, soft drinks are helpful as a dehydrated body cools faster.

Also important is the right clothes. Experts advise not to wear too many layers of clothing so that warm, insulating layers of air can collect between the layers. Mittens are better than regular gloves. The underwear should wick moisture away from the body as sweat on the skin increases cooling later. Skiers know the effect when they sit in the lift after a hard descent and the wind whistles around them. Therefore, if one is too warm in a moment, it's better to put down a shift and put it back on later.

In addition, one should pay attention to the first signs of frostbite all the time. As the spots eventually go numb, many often do not realize how serious their skin is. In addition, frostbite can also form under clothing, such as when gloves do not warm enough.