Hydrocution: what is it?

the hydrocution phenomenon is also called, perhaps more explicitly, thermal shock. Hydrocution occurs when there is a large difference in temperature between that of the body and that of the water. It actually corresponds to a syncopal accident or vagal discomfort.

Cold water — below 18°C ​​for adults and 20°C for children — causes vasoconstriction, including a decrease in the diameter of the blood vessels. A vasoconstriction all the more damaging as it is done at large speed. In water, in fact, the body cools down some 25 times faster than inair. The arterial pressure increases and to restore the situation, the heart slows down its beats. The brain is then no longer properly irrigated.

Consequences that can be dramatic

To protect yourself from the risk of hydrocution, you must therefore naturally avoid plunging suddenly into the water, especially when it is cold. It is also advisable to wet, before the rest of his body, the areas richest in thermal receptors such as the neck, face or back. You should also avoid bathing in sun prolonged or to make an effort physical intense before diving into the water. On the other hand, contrary to popular belief, scientific studies do not recommend avoiding bathing after eating. But at the slightest symptom, it is better to get out of the water without delay.

But what are these symptoms? Itching, chills, cramps, intense fatigue, headache or visual or auditory disturbances may occur. These are the harbingers of respiratory arrest and loss of consciousness, or even heart attack. If a person is in the water when these symptoms occur, then they are at risk of drowning. In France, 500 hydrocutions are counted each summer out of some 20,000 drowning accidents.