Surviving in cold water

Sailing on Canadian waters is certainly a pleasure. But, the water can be particularly cold in many places. And, since cold water can paralyze muscles and gradually lower the temperature of the heart, brain and other vital organs, it is better to know how to react if you or someone else falls into it. Here are the three stages of immersion you may encounter and tips on how to react appropriately.


1st stage: cold water shock

When contact with cold water is sudden, several effects can be felt, such as muscle spasms or an increase in heart rate and blood pressure. Are you a good swimmer? Good for you. But, know that this ability may not be of any help to you. In fact, hypothermic shock can be more fatal than hypothermia, as there is a risk of choking on water, having a heart attack or having a stroke. This is where a lifejacket or personal flotation device (PFD) is of crucial importance: they allow you to float and not drown.  Once in the water, it will be much more difficult to put one on because of the physiological changes the body undergoes.


2nd stage: swimming exhaustion

If you fall into the water, make sure you conserve your energy and heat. If you swim, the risk of exhaustion is one of the greatest dangers. Your movements will become more and more challenging and it will become more and more difficult to grab onto the boat or handle distress flares. Since unnecessary movements will consume the energy your body needs to survive, swim only when necessary, either to join other shipwrecked people or to be safe. Above all: don't swim to warm up!


Instead, grasp a floating object by getting out of the water as much as possible. Cross your arms on your chest and bring your thighs back close to your arms to limit body heat loss. If there are several of you, snuggle up against each other, making sure the sides of your torsos touch, wrapping the middle or lower part of your back with your arms and intertwining your legs.


3rd stage: hypothermia

The more time you spend in the water, the higher the risk of hypothermia. Your body temperature may then drop below 36 degrees Celsius, which results in impaired judgment and diminished ability to control your muscles. A person in a state of hypothermia may have several symptoms, including: 

  • tremors, continuous shivering, slurred speech, more or less conscious state or loss of consciousness
  • weak, irregular or absent pulses
  • slow breathing
  • loss of control or lack of coordination of movements due to numbness in hands and feet
  • irrational behaviour
  • confusion or drowsiness
  • respiratory arrest
  • daze, negligent or distracted behaviour
  • hallucinations
  • dilated pupils


Surviving in cold water: 5 tips for being well prepared


  1. Before casting off, put on a lifejacket or PFD approved in Canada and make sure everyone on board wears their own. If you feel that your boat is at risk of sinking and you have either a dry suit or a wet suit or an immersion or survival suit, put it on. It will help you keep your head above water and conserve your energy.
  2. Be well prepared before you leave and tell someone you trust. Tell them your itinerary and the expected date of return.                                                                                                                    
  3. Check the weather before leaving and on the water, be aware of any changes that may affect your navigation.                                                                                                                                        
  4. Do not go alone and check the safety equipment on your boat.                                                                                                                                                                                                                                        
  5. Drinking alcohol may interfere with your judgment. Avoid consuming it.



Sometimes prevention is better than cure. That's why it's a good idea to check the operation of your safety equipment in a safe environment, such as a swimming pool or in warm, calm water. Feel free to practice survival techniques with friends!




Nautiguide : Surviving in cold water (page 371-373)

Canadian Red Cross : hypothermia and cold water

Camp de survie en eau froide (in French only)




The content in this article is for information purposes only and is not intended to be relied upon as professional or expert advice. Aviva and the Aviva logo are trademarks of Aviva plc. and are used under licence by Aviva Canada Inc. and its subsidiary companies.