Entering Cold Water Suddenly Can Cause Abnormal Heart Rhythms

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Medically Reviewed by Dr. Sarat Chandra (MBBS, MD, Dm),
September 29, 2020

Effect of Cold Water Immersion on Heart

Effect of cold water immersion on heart

Cold water immersion heart attack: Beware of cold-water immersion even if you are young, fit, and healthy reports new research done by researchers at Portsmouth University. Those who plunge into cold water to escape hot and sunny weather must take precautions because short-term benefits can inflict severe damage to the heart in the form of arrhythmias (abnormal heart rhythms). The abnormal heart rhythms can sometimes become fatal and life-threatening. Those who love cold-water immersion must heed to this research.

Before carrying our discussion forward, let us try to answer the following few questions.

What is the link between cold-water immersion and the recent upsurge in immersion-related deaths?

When someone enters into cold water, an array of changes take place in the body and the body’s reaction to those changes can be intense, uncontrollable, and may take place within a few seconds of immersion. Sometimes, the body’s responses can even lead to severe heart problems and drowning.

According to Professor Tipton and Professor Mike Shattock of King’s College London, rapid submersion in cold water spontaneously triggers two powerful responses in the body – which are combined with holding breath. The interaction of such responses can cause conflict for the heart. The study has been published in the Journal of Physiology.

The First Response

When you take cold water shower it triggers a fight-or-flight response – owing to which adrenaline and other stress hormones (epinephrine) get released in the bloodstream causing the blood vessels that supply blood to the skin to narrow. When this happens, more blood flows to the heart making the heart work even harder. In addition to this, stress hormones also get into the bloodstream causing a disturbance in the normal rhythm of the heart. This will not cause any trouble for a healthy person with a healthy heart but could become problematic for someone prone to arrhythmias. The cooler the water, the greater is the risk – potentially leading to lower heart rate and high blood pressure. Owing to this response, some highly sensitive individuals faint in a cool water pool due to a very low heart rate.

The Second Response

Effect of cold water immersion on heart: When you enter into cold water, your body’s cold shock response increases your heart rate and causes hyperventilation.

Breathing increases with an initial gasp followed by hyperventilation (rapid breathing in excess to the body’s demand can cause chest pain, dizziness, and tingling sensation in toes and fingers), and then reduction in breath-holding time.

Hyperventilation work in opposition to the diving response – which tends to conserve oxygen. In this situation, your autonomous nervous system goes into a conflicting situation causing your heart to beat abnormally with abnormal rhythms – sometimes, leading to death. Cold shock response can cause drowning very rapidly after immersion – even good swimmers may succumb to rapid drowning. This is, in fact, the worst effect of cold water immersion on heart.

And, the next critical question is…
Which is the most dangerous time for cold-water-immersion-related deaths?

People tend to go into cold water when temperatures upsurge without realizing that very cold water can become dangerously cold if they suddenly enter into water streams.

According to the research at the Extreme Environments Laboratory, several people died after entering cold water during summers. The cause of death in these cases has been attributed to heart-related abnormal responses.

Why immersion-related deaths peak during summer?

During summer death rates peak because people go back to water-based activities. According to WHO, every year nearly about 1.2 million people die due to immersion-related deaths across the world. These numbers are more in children than the number of deaths due to polio, HIV, TB, and malaria. The irony is that more than 67% of immersion deaths occur in strong swimmers and 55% of these deaths are quick.

What is the solution for those who still love to enter cold water?

According to Prof. Tipton, those who want to enter cold water should follow a slow and steady approach. This means they should enter slowly and in a controlled manner to reduce the risk.

Several researchers, scientists, and cardiologists agree with Prof. Tipton. They also recommend people follow the precautions suggested by the professor.


People who love entering cold water must enter slowly by acclimatizing themselves well with their surroundings.