I’m as happy as anyone to see this warmer than normal weather we’re having here in Wisconsin. (Hopefully, we won’t have to pay for it with a colder than normal June and July.) I do have a serious concern, though, when we start getting these days in the 60’s so early in the season. Cabin-feverish, water-starved paddlers are tempted to head out on the water without realizing the potential dangers of capsizing into 33-degree water. I know I have talked about it before, but it bears repeating every year. “Cold Shock Kills!”
Believe it or not, hypothermia is not the major concern when paddling on cold water. Something known as “cold shock” is much more likely to kill a canoeist or kayaker who accidentally falls into water that is less than 60 degrees. The farther below 60 degrees, the greater the danger. As I have told every kayaking class I have taught in the last 10 years, you need to dress for the water temperature. When you fall into the water, especially if your head goes under water, your body is going to experience some physiologic responses that you can’t really control. 1) An immediate gasp reflex followed by hyperventilation 2) Possible cardiac arrest, especially for those persons with a heart defect or disease.
I strongly encourage everyone to get a copy of the book, “Hypothermia, Frostbit, and other Cold Injuries: Prevention, Survival, Rescue, and Treatment” by Gordon G. Giesbrecht, Ph.D. and James A. Wilkerson, M.D. (The title is longer than the book.) Make sure to get the updated second edition and read chapter 5 on “Cold Water Immersion”. The best way to prevent cold shock is to enter cold water slowly and keep the head out of the water (that should be easy to do when your canoe or kayak tips over unexpectedly). The next best way to prevent cold shock is to make sure that your body is protected from coming in direct contact with that cold water. That’s where a drysuit comes in. The majority of your body’s surface area and all of the critical core areas are kept dry by a drysuit. Since water robs your body of heat 25 times faster than air, this is a very important advantage of a drysuit over a wetsuit. But, you say, divers will wear very thick wetsuits in cold water. That is true, but if you ask them, many divers will tell you that they also pour very warm water into their suit before getting into the water to prevent that shock to the system that occurs if you just jump right into the cold water. Again, this option is not a very practical solution for paddlers who don’t know when they might end up in the water, not to mention that a 5-mm thick wetsuit is not very comfortable to paddle in.
Dr. Giesbrecht talks about his “One Minute – Ten Minutes – 1 Hour” slogan that you should remember if you fall into water. You have 1 minute to get your breathing back under control after falling into cold water (assuming you have not aspirated a lungful of water already with your gasp reflex). Hyperventilation and uncontrolled gasping make it difficult or impossible to prevent yourself from breathing at the wrong time, like when a wave is washing over your face. If you do not control your breathing and prevent panic, you will likely drown very quickly in that first minute. The “Ten Minutes” refers to the amount of time that you have before you will lose motor control and coordination in your extremities. Whatever you need to do to save yourself better be done before those 10 minutes are up or you will not be able to use your fingers or arms and legs to reach, grab, pull, kick, swim, or do anything else to get to safety. This stage is referred to as “cold incapacitation”. Keep in mind that swimming will actually hasten cold incapacitation, so you may have less than 10 minutes if you choose to swim for it. Hypothermia won’t actually progress to the stage that will kill you until about an hour, if you can keep your head out of the water so that you don’t breathe in water and drown first.
My suggestion, you should not be in your boat on the water for several weeks unless you are wearing a drysuit. As always, you definitely should be wearing your life jacket (PFD). Beware the high water in many of the rivers this time of year. (I haven’t even gone into any of the dangers of paddling in a river that is running at or near flood stage especially at a time of year when your paddling skills are at their rustiest. I will leave that for another post.) When you do see paddlers out on the water this time of year, try to talk to them. The experienced and skilled paddlers should be able to tell you about the precautions they have taken to protect themselves from cold shock. If the paddlers you see are obviously not dressed to be out on the water this time of year, try to gently and tactfully tell them about the dangers of cold shock. Every year it seems that there are reports of sudden unexpected drownings that take place in March, April, and early May. Most of us never get to hear the autopsy results. I would bet that most of these cases are likely the direct result of cold shock. Let’s all be sensible and make sure we live to paddle in the warmer days of summer.