What is immersion syndrome or hydrocution syncope?

We all remember the summers of our childhood in which our mother or our grandmother told us that After eating we had to wait at least two hours before taking a bath. so that it would not give us a very dangerous “cut of digestion”. And it is very likely that we are repeating the advice to our children.

The reality is that the term “digestion cut” has popular acceptance, but it does not describe well what can happen when we plunge into cold water, which It has nothing to do with the digestive process.

The problem is the temperature difference

In favor of the “digestion cut” are the many people who have felt bad after getting into the sea or swimming pool, with symptoms such as vomiting, dizziness and even fainting.

But what happens is not that digestion is cut off, but that a thermal shock occurs that causes the symptoms of immersion or hydrocution syndrome.

In the most acute cases, loss of consciousness and even cardiac arrest can occur. If the loss of consciousness occurs in the water and the person is not helped, they may drown.

a knee jerk reaction

What really happens to these people It is the consequence of a vagus nerve reaction (the longest of all cranial nerves) when undergoing a sudden change in temperature. The risk of it occurring increases when the water temperature is below 27ºC.

The vagus nerve reaction is instinctive and occurs when receptors in the nose and other areas of the face are submerged in water. At that time, the brain orders the airways to close and the heart rate slows down. the arrival of blood to the organs, except the brain. This reaction allows us to increase the time we can spend underwater without breathing.

The problem arises when this reflex occurs abruptly due to the sudden change between body temperature and cold water (thermodifferential shock).

In summer the problem multiplies because body temperature may be increased by sunbathing or strenuous exercise. Having eaten recently can also increase it a bit, but, as we have seen, it is not the decisive factor.

How can immersion syndrome be prevented?

There are no clear studies, but it is recommended take a number of steps:

Avoid sudden immersion in cold water. Avoid getting into the water after prolonged exposure to the sun. In the pool, take a shower before getting in the water to acclimatize the body. Do not bathe in water that is too cold, especially if it is below 27ºC. Avoid vigorous physical activity before bathing in very cold water. Learn basic resuscitation techniques for use in an emergency. In summer pay special attention to children and teach them to behave responsibly in the water. Gradually moisten the body before submerging, since in case you experience any discomfort they can take you out of the water quickly.

What to do if you feel discomfort?

If you suspect that the discomfort may be due to thermal shock, you muste lie down in the shade with your legs higher than your head and rest, while waiting for the arrival of medical help.

If the person has fainted, check if they are breathing. If so, he stands on his side, with one arm under his head and one knee bent to maintain the position, awaiting the arrival of the sanitarios.

If the person is not breathing, it is necessary to urgently perform a heart massage.