Understanding Cold Water Shock: What You Need to Know

Title image. Picture of a mans hand being held out of the water with the rest of the man beneath the surface. Written over it are the words "Understanding cold water shock: what you need to know".

Understanding Cold Water Shock: What You Need to Know

Estimated reading time: 7 minutes

Cold water shock is a sudden and potentially deadly reaction that can occur when a person enters cold water. It can cause gasping, hyperventilation, and even cardiac arrest. Understanding the symptoms and how to prevent it can be life-saving, especially for those who enjoy water activities. Read on to learn more.



What is cold water shock?

Cold Water Shock is your body’s immediate and often extreme reaction to sudden immersion in cold water. It’s important to note that “cold” in this context doesn’t necessarily mean icy or frozen. In many cases, water temperatures of 15°C (59°F) or below can induce cold water shock, though it’s most intense in much colder temperatures.

Here’s what happens during cold water shock:

  1. Gasp Reflex: The most immediate danger. As soon as you hit the cold water, you may involuntarily gasp and, if underwater, this could lead to drowning.
  2. Hyperventilation: After the initial gasp, rapid breathing might follow. This makes it very difficult to hold your breath.
  3. Increased Heart Rate & Blood Pressure: Cold water can cause a spike in heart rate and blood pressure. For some people, especially those with underlying heart conditions, this sudden change could be harmful.
  4. Loss of Muscle Control: The cold can also affect your ability to move, making it hard to swim or even tread water.
Green and black image of a mans face and torso under water with bubbles coming away from his face.

When and how might you experience cold water shock?

Accidentally Falling Into Cold Water:

In the UK we have an abundance of tranquil rivers, picturesque lakes, or the winding paths of canals. These water bodies, with their calming views, often invite pedestrians for a stroll or a leisurely sit-down. However, even with the most careful steps, accidents can happen. Slippery banks, unstable surfaces, or even a misjudged step can unexpectedly land you in the water. An accidental tumble into such cold waters, even if they appear calm and inviting, can rapidly induce cold water shock. Your body is unprepared for the sudden temperature change, leading to an involuntary and dangerous response. This scenario emphasises the importance of being cautious and aware when near water bodies, and the need to educate others, especially children, about the potential risks.

Recreational Activities:

The allure of water is often irresistible, especially during our warmer months. Many adventurous souls partake in wild swimming, which is the act of swimming in natural waters such as lakes and rivers. Add to this the thrill of water sports, from kayaking to paddleboarding, and the fun of spontaneously jumping off a pier into the sea or into an old quarry. While these activities offer exhilarating experiences and are fantastic ways to connect with nature, they also come with their inherent risks. Even during seemingly warm days, water temperatures, especially in the deeper parts or shaded areas, can remain very cold. Engaging in these activities outside the peak summer months increases the risk of encountering colder waters. Participants should be well-informed about the potential dangers of cold water shock and take necessary precautions.

Ship or Boat Accidents:

With our extensive coastline and numerous inland waterways, we are lucky to have numerous opportunities for boating adventures. From the casual sailor enjoying a weekend out on the water to the professional mariner navigating the coastal routes, the sea and inland waters are always bustling with activity. But the unpredictable nature of waters means that accidents, such as capsizing or someone falling overboard, are an unfortunate reality. In these situations, the immersion in water is sudden and unexpected. Moreover, UK waters, due to their geographical location, tend to remain chilly even in the height of summer. Therefore, someone involved in a ship or boat accident faces the imminent risk of cold water shock. The situation underscores the importance of safety measures, having emergency protocols in place, and ensuring that all on board are wearing or have easy access to life-saving equipment.

How can you prevent cold water shock?

There are several ways to prevent cold water shock when participating in water activities. First, always wear a life jacket or personal flotation device. This will help keep you afloat and reduce the risk of drowning if you do experience cold water shock. Second, avoid sudden immersion in cold water. If possible, ease yourself into the water slowly to allow your body to adjust. Third, avoid alcohol and drugs when participating in water activities. These substances can impair your judgment and increase the risk of cold water shock. Finally, be aware of the water temperature and weather conditions before entering the water. If the water is too cold or the weather is too severe, it may be best to avoid water activities altogether.

What are the symptoms of cold water shock?

The symptoms of cold water shock can vary, but typically include gasping, hyperventilation, and increased heart rate. Other symptoms may include muscle cramps, confusion, and loss of coordination. In extreme cases, cold water shock can lead to cardiac arrest and drowning. It’s important to be aware of these symptoms and take precautions to prevent cold water shock when participating in water activities.

Picture of a woman in a white shirt floating on her back in the sea. She has her arms out to the side as she is floating in the shape of a star.

How can you stay safe while swimming in cold water?

To stay safe while swimming in cold water, it’s important to take precautions and be aware of the risks. Always wear a life jacket or other flotation device, even if you are a strong swimmer. Avoid swimming alone, and make sure someone knows where you are and when you plan to return. If you are swimming in a natural body of water, be aware of the water temperature and the potential for sudden changes in weather conditions. Finally, if you are not an experienced cold water swimmer, consider taking a class or getting training before attempting to swim in cold water.

How to prevent or cope with cold water shock:

  1. Be Aware: Know the temperature of the water before you decide to enter. Don’t just jump in without checking.
  2. Enter Slowly: Allow your body to acclimatise by entering the water gradually rather than diving in.
  3. Wear Appropriate Clothing: If you’re participating in water activities, wearing a wet suit or dry suit can help.
  4. If You Fall In: Try to stay calm. Avoid thrashing about or gasping. Float on your back and focus on breathing slowly.

What should you do if you experience cold water shock?

If you experience cold water shock, it’s important to try to stay calm and keep your head above water. Focus on controlling your breathing and try to float or tread water until the initial shock passes. If possible, try to get out of the water as soon as you can. Once you are out of the water, seek medical attention immediately, even if you feel fine. Cold water shock can have delayed effects on the body, and it’s important to get checked out by a medical professional to ensure your safety.

Being aware of cold water shock and its dangers can save lives. Always exercise caution when around or in cold water, especially in the UK where many water sources remain chilly throughout the year.


Understanding Cold Water Shock: What You Need to Know

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to top