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The digestion cut

First aid

The «digestion cut» does not exist | First aid

How does it not exist? My grandmother and even my mother used to tell me: «Child waits two hours after the meal before bathing, otherwise it will give you a digestion cut ». 

The reality is that the term "cut of digestion" is a very common expression, popularly accepted. However, it is an inappropriate term, since it is not at all a failure of the digestive process. It is indisputable that it is a classic of the summers but without scientific basis.

And you will say to me: "I have seen with my own eyes people getting dizzy, with nausea, vomiting and even fainting from getting into the water after eating."

Yes, okay, but that has an explanation, regardless of whether you have eaten before or not. 

Discover what actually happens, since you can save many lives:

As we have said, the term "digestion cut" is not real in medical terms. The correct name for these symptoms is known as Syndrome  Hydrocution, caused by athermodifferential shock.

What really happens to these people is a vagal reaction that can occur when submerging in cold water, causing, at best, dizziness, paleness, vomiting ... If it is more serious, the person can lose consciousness and , if you are in the water without company, drowning entering cardiac arrest.

It is more frequent when the water temperature is less than 27ºC  or when there is at least 5 ° C difference between body temperature and water temperature. There is no study that demonstrates a clear relationship with having eaten before or not. This is what the toilets call Hydrocution syndrome caused by thermodifferential shock.

What happens then when we dive in cold water?

Well, when we get into cold water, a phenomenon called immersion reflection. The immersion reflex occurs when receptors present in the nose and other areas of the face are submerged in water (a primitive reflex common in mammals). The information that the face has found water is transmitted to the brain and autonomic nervous system, through vagus nerve. This causes the immediate closure of the airways and various Physiological changes of variable magnitude depending on the thermal contrast with the environment, all this leads to a decrease in heart rate and a reduction in blood flow to all organs except the brain. The immersion reflex is good and allows us to remain, if necessary, more time in the water without breathing.

Up to here everything perfect. But nevertheless the problem comes when this reflection occurs in a abrupt due to the intense change between body temperature and cold water (thermodifferential shock). In summer the problem is multiplied if we add that the temperature of our body is usually raised by having sunbathing or having done intense exercise.

Therefore, the sudden change of temperature between cold water and the heat of our body can be dangerous? 

Yes. The organism requires considerable effort to maintain the body temperature at 37 ° C, which must be achieved in a few moments, with more reason when the water temperature is colder. If it fails, a rapid decrease in body temperature occurs, followed by a rapid retention of breath that can cause syncope and the victim may drown, entering cardiac arrest.

How to prevent it? 

There are no studies that have been done to show that some or other standards have some degree of evidence.

However, from Proyecto Salvavidas we recommend the following:

  • Avoid plunging sharply into cold water.
  • Avoid entering the water after prolonged exposure to the sun.
  • In the pool, go through the shower before going into the water to acclimatize the body.
  • Avoid bathing in too cold water, especially if it is below 27ºC.
  • Avoid intense physical exercise before bathing in very cold water.
  • Education on water safety measures and resuscitation.
  • In summer, we watch the little ones in the house and teach them responsible behavior in the water.

It is advisable to progressively wet the body before submerging, as if you feel some dizziness or bad feeling you can get out of the water as soon as possible.

By common sense, avoid entering the water with digestion in progress because, although it is not always the reason for the shock, it can influence sometimes.

What to do before a drowning? The need to know the techniques of cardiopulmonary resuscitation and defibrillator management. 

The treatment of a drowning victim consists of four phases:

1 Aquatic rescue.

2 Basic cardiopulmonary resuscitation. (We will expand the information in the following post).

3 Advanced cardiopulmonary resuscitation.

4 Post-resuscitation care.


Although not all drownings are triggered by this Hydrocution Syndrome (not "digestion cut"), it is time to take preventive measures such as those described above, know the cardiopulmonary resuscitation and defibrillator maneuvers that are very important, since if we initiate the rescue maneuvers at an early stage, the chances of the victim recovering without neurological damage are high.


From Proyecto Salvavidas we wish you a good summer! And be very careful with cold water and sudden changes in temperature.


Matías Soria.

Training Department ANEKS3 SL

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Installation of external defibrillators, maintenance, spare parts, repairs, training and use of the defibrillator, registration in Autonomous Communities.

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