Hydrocution

A hydrocution is generally a cardio-ventilatory stop with the difference of Température between a liquid (of the Eau, from where the prefix " hydro") and the Skin. Such a shock can cause a loss of consciousness and thus a Noyade. According to the Editions Larousse , the term is recent: 1953, and come from " electrocution " , itself, English term, manufactured starting from " electro " + the " - cution " of " execution ".

Mechanism

When the weather is hot, the blood-vessels located under the skin are very open (Vasodilatation) in order to support the peripheral circulation which makes it possible to evacuate heat. The cardiac rhythm also increases in order to accelerate this cooling.

If one enters cool water brutally, the skin cools very quickly, and the vessels will contract quickly (Vasoconstriction). This made ebb peripheral blood towards the interior of the body, and causes an increase in the blood Pressure.

To fight against this hypertension, the heart will slow down (action of the parasympathetic Nervous system). So the Cerveau will be less better irrigated, and the deficit of provisioning of Dioxygène which follows causes the loss of conscience.

How to avoid it?

To avoid it, it is necessary to prepare the circulatory system with this temperature variation, therefore it is necessary:

to wet before the bathe the zones richest in thermal receivers: Nape of the neck (Hypothalamus), Thorax, Back;
to enter water gradually;
to avoid the heavy alcoholic drinks and meals before the bathe;
not to bathe during the Digestion |date= October 1st, 2007 ;
not to only bathe or in not supervised zones.

The risks are greater if water is cold or following an exposure prolonged to the Sun.

Precursory signs

In the event of occurred of one of the following signs, it is immediately necessary to leave water and to warn his friends:

headaches
itchings, Urticaria;
shivers, tremors;
eye trouble or auditive;
sudden feeling of intense tiredness or anguish;
Cramp S.

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