Cold Water Shock
For east coast sea kayakers, cold water is part of paddling our coastline. However how many paddlers understand the mechanics of cold water shock when capsizing or entering the water? So following is a summary of what to expect and the effects and implications of cold water shock on sea kayakers.
Stage 1 - Cold Shock
"The sudden lowering of skin temperature on immersion in cold water represents one of the most profound stimuli that the body can encounter."
- Golden and Tipton in Essentials of Sea Survival
Translation: Short of being hit by a bus or struck by lightning, the cold shock is one of the biggest jolts that your body can experience. If you gasp underwater, you will immediately drown. Cold shock is a lot more complicated and dangerous than just gasping for air. The instant that cold water makes contact with your skin, you will experience a number of potentially lethal shock responses. These fall into three categories:
Threat No. 1 - Loss of Breathing Control
Threat No. 2 - Heart and Blood Pressure Problems
Threat No. 3 - Mental Problems
Threat No. 1
Loss of Breathing Control
2-3 Minutes or More
During the first several minutes of cold shock, and possibly for much longer, most people find it impossible to get their breathing under control. Breathing problems include gasping, hyperventilation, difficulty holding your breath, and a scary feeling of breathlessness or suffocation.
This isn’t just a little gasp, like the kind you’d experience if somebody jumped out of a closet and scared you. It’s a huge gasp that totally fills your lungs. You may experience several of these gasps in a row. If your head is underwater when you gasp, you will immediately drown, and without the support of a PFD, you will head straight for the bottom. Before cold shock was identified as the cause, this phenomenon was known as Sudden Disappearance Syndrome.
Gasping is immediately followed by hyperventilation - very rapid, out-of-control breathing. Swimming as short a distance as 6- 10 feet while hyperventilating is often impossible, even for good swimmers. When you’re breathing very rapidly (like 65 times per minute) swimming strokes cannot be synchronized with respiration. The result is a swimming failure. If you're not wearing a PFD, you will drown.
Hyperventilation also results in hypocapnia, a reduction of the level of carbon dioxide in your blood which can cause:
-Ringing or buzzing in your ears.
-Numbness of your fingers and toes.
-Cramping of your hands and feet.
-Reduced ability to complete simple and familiar tasks.
-Loss of consciousness.
-Difficulty Holding Your Breath
Coldwater immersion greatly reduces the length of time that you can hold your breath. An average person’s ability to hold their breath in water below 60F (15C) is one-third of what they can do in warmer water. The lower the water temperature, the greater the problem. One study of volunteers in 41F (5C) water found average breath-hold time reduced from 45 to 9.5 seconds, with one subject reduced to 0.2 seconds. This will greatly affect your ability to roll in particular re-entry and rolls.
Feeling of Suffocation
Paradoxically coinciding with hyperventilation is a strong claustrophobic feeling of not being able to get enough air. This frightening sensation, which continues for up to three minutes before gradually declining, increases the potential for panic and disorganized behaviour in the water and makes it much more difficult to eventually gain control of your breathing.
Threat No. 2
Heart and Blood Pressure Problems
Coldwater immersion causes an instantaneous and massive increase in heart rate and blood pressure because all the blood vessels in your skin constrict in response to sudden cooling, which is far more intense in water than in air. In vulnerable individuals, this greatly increases the danger of heart failure and stroke.
Threat No. 3
The moment you hit the water, the cold shock causes a huge reduction in your ability to think and function. This can continue for a long time – even after you get out of the water. Problems include:
Inability to think clearly
Inability to evaluate options
Inability to carry out a plan of action
Freezing in place
Failure to act
If the water temperature is below 40F (5C) add Severe Pain to the list
Real World vs Training
Coldwater climatisation is part of any good sea kayakers training regime and even though we know what to expect, cold water shock can still be a huge problem for us. We are familiar with cold water and we know in advance what’s going to happen. And of course, we take precautions like taking note of any medical conditions and training in a safe environment and within safe parameters. Nevertheless, despite all that reassurance, we can experience cold shock for two to three minutes, and it can take up to five minutes for us to stabilize their breathing at around twice the pre-immersion level.
The Real World
Out in the real world, of course, the situation is far more intense. Paddlers are taken by surprise, and once they’re in the water, they very quickly realize that they’re fighting for their lives.
Many sea kayakers are;
Unfamiliar with cold water.
They’re taken by surprise and stunned.
They know they’re in desperate trouble.
They’re very upset and afraid.
All of the courses at NOMAD Sea Kayaking place an emphasis on cold water shock and the effects of hypothermia on our paddlers. For more information please contact us or visit our 'Courses' page.