Cold shock is often presented as an afterthought in a discussion of hypothermia, and yet it can take you down almost instantly, well before hypothermia has a chance to set in. Cold shock is more immediate. What is cold shock? Well, it’s an almost instantaneous reaction to immersion in cold water. A variety of symptoms can cause almost immediate incapacitation and even death. Let’s have a look…
What you need to know first is that the risk & symptoms of cold shock really kick in when water temps are around 55f and increase as the water temps continue to sink. Air temperatures are not relevent. Sudden immersion at these water temperatures can cause uncontrolled gasping which, if your head is under water at the time, will lead to nearly instant drowning. This is one reason kayakers have been found upside down, seemingly never even attempting to roll or wet exit. Cold shock can also play havoc with your breathing even if you keep your head above water. It can cause hyperventilation which can lead to panic and a condition called Alkalosis, which can cause confusion, dizziness and possible loss of consciousness well before hypothermia has time to set in. Some folks will experience breathlessness, or the inability to breath. From here, dizziness, panic and an overwhelming sense of claustrophobia can take hold causing hyperventilation once again. The point to take home is that cold shock can kill you instantly or slow you down and put you into a state where you’ll be making bad decisions long before the onset of hypothermia.
This article links to a Cold Water Primer for Sea Paddlers article on AlaskaKayakSchool.com... which in turn leads (via a broken link) to a superb, 7 page introduction on AtlanticKayakTours.com.
The latter isn't overly long, but covers:
- Cold Shock
- How Your Body Regulates Core Temperature
- Types & Signs of Hypothermia
- Treatment of Hypothermia
- Cold Water Equipment
Mario Vittone's Staying Alive in Cold Water (1-10-1) discusses "Cold Water Boot Camp, USA" and elaborates on the 1 – 10 – 1 principle of cold water immersion: "three numbers that will help you remember how to survive the three phases of an unexpected dip into cold water". This is also discussed here.. with a better graphic. Combining the two sources:
Phase 1: The cold shock response – accidentally falling into cold water (say, under 59° F) is an assault on the body’s senses. Characterized by uncontrollable gasping and disorientation, the first moments can be the most dangerous. So for that first minute (1), do nothing but keep your head above water, try and stay calm, and control your breathing. The gasping will stop and then you’ll be able to work on getting yourself safely out of the water.
Phase 2: Swim failure – or the loss of muscle control – happens to everyone who stays in cold water long enough. If you’re not wearing a life jacket – regardless of how strong a swimmer you are – you will drown long before you ever become clinically hypothermic. The longer you stay in, the weaker you become. So after that first minute of just staying calm, you have about ten (10) minutes to try and self rescue. If you haven’t gotten out of the water by then, you’re not going to. Conserve your energy to delay phase three.
Phase 3: Hypothermia – core body temperature of 95° or less – takes a surprisingly long time to happen. The point here is not to panic. Depending on variables like air and water temperature, no matter how uncomfortable you are (and trust me – you will be) you will have an hour (1) or more before you lose consciousness from hypothermia.
Cold Shock and cold incapacitation can happen while a victim is normal thermic. Once you lose strength and coordination it will not come back. Use what you can when you an.
The gCaptain blog contains an even better article by the self-same Mario Vittone. This is entitled The Truth About Cold Water, and notes it "is impossible to die from hypothermia in cold water unless you are wearing flotation, because without flotation – you won’t live long enough to become hypothermic".
When the water is cold (say under 50 degrees F) there are significant physiological reactions that occur, in order, almost always.
- You Can’t Breath
- You Can’t Swim
- You Last Longer than You Think
He goes on to discuss:
- Rescue Professionals Think You Live Longer...
- Out of the Water is Not Out of Trouble
The article encourages viewing of Cold Water Boot Camp, dubbing it "one of the best 10 minutes on immersion hypothermia ever produced"...
This video can be followed up through Beyond Boot Camp resources:
- Lectures - The stages the body encounters and experiences during cold-water immersion, hypothermia, and recovery.
- Extractions - Utilizing many different types of safety gear available to any rescue-responder and boater.
- Triage - For all victims of cold-water immersion and with particular attention to mild, moderate, and severe hypothermia.
- Transport - Demonstrating proper techniques with different types of rescue equipment.
- Extras - Ambulance Transport to Hospital and Thermal Protection Test and interviews with the responders.