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Cold Water Shock: Causes, Symptoms & Phases

March 29, 2023

Many of the fatal boating accidents occur out of season, in the months when the water is cold. Cold-water shock occurs when you are suddenly plunged into frigid waters. In this blog, we will discuss the causes, body’s reaction, symptoms, and phases of cold water shock.

What is cold-water shock?

Cold water shock is a physiological response that occurs when a person is suddenly immersed in cold water. It can happen even in relatively mild water temperatures. Cold water shock can cause the body to react in ways that can be dangerous, even fatal. It is among the common causes of recreational boating deaths

Is cold water chock dangerous?

Hyperventilation, rapid heart rate, increased blood pressure, and decreased dexterity are all symptoms making cold water shock very dangerous. In severe cases, cold water shock can cause unconsciousness, cardiac arrest, or death.

It is important to do everything you can to avoid exposure, especially in Canada where the waters are colder. Examples are:

  • Respect the capacity limits of your vessel to minimize the risk of capsizing.
  • Being qualified when engaging in diving.
  • Ensuring everyone onboard has a life jacket that fits

What are the symptoms of cold-water shock?

The symptoms of cold shock can vary depending on the individual and the water temperature as well as the duration of exposure. There are three stages, each characterized by different symptoms.

Cold Shock Response – 1 Minute

During this phase, the person experiences an involuntary gasp reflex, which can cause them to inhale water. The gasp reflex is followed by hyperventilation, which can lead to a decrease in carbon dioxide levels in the blood. This can cause the blood vessels in the skin to constrict, which can lead to an increase in blood pressure and heart rate.

During this time, concentrate on avoiding panic and getting control of your breathing.

Cold Incapacitation (Short-Term ‘Swim Failure’) – 10 Minutes

During this phase, the person may experience a decrease in muscle function and coordination, which can make swimming or staying afloat difficult.

Again, avoid panic. Air trapped in clothing can provide buoyancy if you remain still in the water. Swimming or treading water will greatly increase heat loss and can shorten survival time by more than 50%.

Hypothermia – 1 Hour

During this phase, the person’s body temperature may drop to dangerous levels, and they may experience extreme fatigue, confusion, and disorientation. Finally, hypothermia sets in, and without rescue and proper first aid treatment, unconsciousness and death will follow.

Hypothermia can be a consequence of cold-water shock, but it is a separate condition which requires a special response and immediate medical attention.

How to survive cold-water shock

If you should fall into the water, all efforts should go to getting out of the water by the fastest means possible, usually via the reboarding device. Call for help with a VHF marine radio.

It is very important when navigating in cold water, that everyone should wear their PFD or their life jacket since it may save their life. If possible, wear an immersion suit or an anti-exposure suit. These are usually one-piece suits that act both as a jacket to keep you warm and as a personal floatation device.

Learn about boating safely on cold waters with Drive a Boat Canada

Cold water shock is a serious and potentially fatal condition that can occur when a person is suddenly immersed in cold water. Understanding the causes, body’s reaction, symptoms, and phases of cold water shock is critical for anyone who enjoys water activities. For more in-depth coverage, contact us now to get your boating license.