Hypothermia versus Cold Water Shock

[RobLL]

http://www.seattletimes.com/seattle-news/seasons-inviting-waters-have-chill-enough-to-kill/

A well researched article, and warning for those coming to cold water country from warm water country.

[C-Val]

Just a random question re: hypothermia since I boat in cold water.

I have an older Mustang flotation jacket that I seldom wear.
I tend to throw my regular lifejacket over my winter jacket. Would my flotation jacket be better if I was in the water or would it make no difference?

thanks

[thataway]

[Robert H. Wilkinson]

[Phil Barnes]

This film clip "Cold Water Boot Camp" made believers out of us. We saw it at a Coast Guard Auxiliary training course. Rescue Swimmers and high caliber swimming athletes jumped into Lake Erie under safe and controlled conditions and it is alarming to see how quickly these fit swimmers lost ability to swim or reboard. A life jacket makes the difference for survival assuming you survive the shock of the first minute. If you are afloat you can be rescued by others. The film illustrates the 1-10-1 principle. Here's to safe boating in cold waters! Phil

https://www.youtube.com/watch?v=J1xohI3B4Uc


http://www.coldwaterbootcamp.com/pages/home.html

[Foggy]

I used to be an avid paddler and live in northern Michigan where the water can
be cold. I thought it would be a good idea to look into being on or in cod water.
I learned some things and wrote the following shared with my local paddle club.

It is not required to be a paddler to suffer the effects of cold water with sudden or
prolonged immersion. And, it is good to know there is more than hypothermia
that can claim you.

Aye.
_______________________________________________________
COLD SHOCK - INFORMATION TO HELP KEEP PADDLERS SAFE
Martin Strand III
March 22, 2006



The American Canoe Association (ACA) says, “The keys to managing any risk are knowledge and skill.” (1) The former is the purpose of this paper; to caution and inform, not frighten. Keep in mind, venturing out on the water to have fun or exercise is optional. Returning home is mandatory.

Before giving in to the temptation of going for that long awaited first, or subsequent, Spring paddle this year on a beautiful warm sunny 70* F day, consider the following, even if you remember to think about the cold water and know about hypothermia.

* In northern latitudes during March, April and May the highest percentage of deaths occur from people going out on dangerously cold water. (2)
* Immersion in cold water kills more paddlers than any other hazard in the sport. (3)
* Cold water itself is the single most serious threat to the survival of a paddler; the colder the water, the more likely cold shock may take you. (4)
* Cold shock kills and occurs long before hypothermia can set in. (5)
* The most common fatal error for paddlers is wearing clothing inappropriate for the cold. (6)

DEFINITIONS

COLD WATER has a number of definitions. In Alaska and British Columbia some sources say it is water below 77* F (25* C) (7) ( or it is water below 70* F (21* C) (9). Others report it is below 60* F (15* C) (1) (6) (10). USCG data shows about 3/4 of all canoe and kayak fatalities occurred in water < 65* F (18* C). (6) Still others call the temperature at which water can be considered cold is “variable”. (11) The important concept for paddlers to recognize is the colder the water, the higher the risks with inadvertent cold water immersion.

COLD SHOCK describes a series of rapid, linked, involuntary and detrimental physiological events in the inadequately protected human body characterized by immediate loss of breathing control, incapacitation and high risk of drowning or sudden death when suddenly immersed in cold water. Most of these immediate body responses are increasingly fatal as the water temperature decreases.

HYPOTHERMIA is a process where the body loses heat to the environment (water or air) faster than it can produce heat. This lowers the body’s core (brain, heart and lungs) temperature with accompanying decrease in bodily functions critical for survival in proportion to the extent of the lowered core temperature. Hypothermia takes time; the rate at which it occurs is proportional to the coldness of the water and the victim’s lack of insulation.
New thinking and research over the past decade has given birth to the concept of cold shock from sudden cold water immersion. This now explains why some experienced paddlers have been found dead in their overturned boats with their paddle still in their hands apparently without having made an attempt to wet exit or why observers of fatal cold water accidents have reported “He just tipped over and never resurfaced” or ”He was a good swimmer and so close to shore but it looked like he was just flailing around and then just went under.” And why, in the most blunt message, 9 elite Marines in March 1968, trained as water safety instructors but wearing only sweat suits paddling the Potomac River on water that was 36* F, after their war canoe capsized, none could swim 100 yards to shore. None survived. (12) This signals that a physically fit person, who is a good swimmer in warmer water, has no guarantee of survival from the adverse effects of cold water unless they have prepared to be immersed. (1)

It is now understood cold water kills by cold shock, drowning and advanced hypothermia. (13) Unless death occurs at any point, this occurs in three continuous phases: an initial cold shock response, a short term immersion and loss of performance phase and long term immersion with onset of hypothermia. (11) This writing addresses the first two since much has been written about hypothermia.


PHASE I: INITIAL COLD SHOCK RESPONSE (1 - 4 minutes)

First, the extremely unpleasant sensation of sudden cold water on skin triggers a cluster of breathing and heart responses; their severity depending on the extent and rate of skin cooling. This immediate neuromuscular reaction can cause a series of huge uncontrollable gasps for air called the INVOLUNTARY GASP REFLEX. If your head is underwater, you immediately drown. It also causes the INABILITY TO HOLD YOUR BREATH while under water from a preimmersion mean of 45 seconds to a mean of 9.5 seconds (one subject averaged less than a second) in 41* F water. (14) Imagine the implication for an unprepared kayaker trying to set up for a roll or wet exit!

However, if you manage to rapidly resurface, you may then have either your lungs full of cold water and can’t breath or you will immediately begin to HYPERVENTILATE, which usually follows the gasp reflex and is characterized by rapid and deep in/out breaths equal to 600-1000% greater than normal breathing (16). The triad of hyperventilation, involuntary gasping for air and LACK OF BREATHING CONTROL makes it easy to inhale water and drown. Also, as higher than normal blood levels of carbon dioxide are being quickly exhaled while gasping and hyperventilating, blood pH rises (respiratory alkalosis) which can cause cardiac arrhythmias, cramps from muscle tetanus, and cerebral vasoconstriction which starves the brain of oxygen resulting in disorientation, confusion and LOSS OF CONSCIOUSNESS.

Simultaneously, cold water on body skin causes constriction of capillaries under the skin. This INCREASES HEART RATE, CARDIAC OUTPUT AND BLOOD PRESSURE. These changes alone may be tolerated by a young healthy person but can be dangerous for older paddlers with hypertension or other underlying heart disease. Other sequellae challenging the immersed paddler for survival in cold water include pain, claustrophobia and disorientation which causes PANIC. This stimulates release of adrenaline in the body (“fight or flight” response) which, normally, is our way of automatically protecting ourselves from harm. Paradoxically here however, it adds dramatically to existing cardiac changes from capillary constriction. These conditions, along with a huge volume of cold water in the lungs cooling the heart with accompanying blood chemistry changes, can precipitate CARDIAC ARREST and sudden death.

PHASE II: SHORT TERM IMMERSION AND LOSS OF PERFORMANCE (1/2 hour)

If cold shock is survived but immersion continues, body cooling proceeds rapidly. Called "cold incapacitation", in minutes this leads to decreased extremity neuromuscular activity and blood flow causing finger stiffness, poor coordination of motor activity and considerable loss of strength. (16) The loss of motor control makes it difficult, or impossible, to perform survival procedures like rolling, reentry, blowing your whistle and signaling for help or grasping a rescue line. Along with disorientation and panic, it can easily account for the reports of apparent “flailing about” of good swimmers in their death throws of cold water immersion. In these critical minutes, amplified by not wearing a PFD, the cold water victim, by inhaling too much water or by inability to maintain survival skills of staying afloat, swimming or grasping a line, ultimately drowns (16).

PHASE III: LONG TERM IMMERSION WITH ONSET OF HYPOTHERMIA

The reader is referred to multiple other sources.

PREVENTION OF COLD SHOCK

1. Do not go out on cold water if capsize is likely; paddle only on warm water. This is not realistic for most.

2. Take the temperature of the water before venturing out on it. Know what you are dealing with.

3. Wear a PFD that will keep your nose, mouth and head out of the water or you can drown without immediate assistance from someone else. Many Class III and V PFD’s worn by paddlers will not right you if you cannot right yourself or are unconscious. (4) Without a PFD in cold water, you can drown without ever coming back to the surface. No second chances here.

4. Wear protective clothing. The critical areas are the torso, head and neck. Dress to balance clothing for water and surface conditions (7) but keep in mind it is the water temperature that deserves most attention for cold shock protection. The colder the water, the more you need protective clothing designed to keep the cold water off your skin which means seals at the neck, wrists, waist and ankles along with a neoprene head and neck hood. Judgment and common sense can help. If you are inexperienced, get advice from an experienced paddler.

Dry suits and neoprene wet suits are uncomfortable and often too warm, many claim, on a nice day but they will protect your torso from the immediate effects of cold water and decrease the chance of cold shock. One source states that without insulative protection underneath, a dry suit is not protection from cold shock. (3)

Polartec 2000, a new high tech tight fitting material with a fuzzy comfortable inner layer and windproof and near waterproof double outer stretchy layers, prevents the rapid movement of cold water to the skin. (15) It acts like a wetsuit and is rated to 2.5 mm neoprene. Different shapes for the corresponding body parts (feet, hands, head and neck, torso) are available. It has promise to decrease cold water mortalities since more boaters may wear it (it’s reportedly comfortable), it insulates and slows water ingress to skin.

ACA (American Canoe Association) Recommendation for Paddling in Cold Water (1)

* When the water temperature is < 60* F, wear “specialized insulating clothing”
* Always wear a wet suit or dry suit
If combined air/water temperature is < 120 * F
If you plan to paddle far from shore in cold water
In milder weather when you expect repeated exposures to cold water

Recommended Layers for Cold Water Paddling (if no full dry/wet suit) (4) (7) (14)

Neoprene head and neck hood (**) or
Fleece/wool neck warmer and skullcap (**)
Poly pro long johns (**)
Hydroskin farmer john (**)
Wind/rain/paddle pants
Neoprene booties (**)
Poly pro top (**)
Hydroskin top (**)
Fleece/wool top or sweater
Paddle jacket (best: dry with neck, wrist and waist seals)
Pogies or paddle gloves (**)
(**) Could be replaced by Polartec 2000

5. Never paddle alone on cold water.

6. Some recommend practicing voluntary cold water exposure (progressively colder showers before practice cold submersion) in order to build up your tolerance to cold water. (3) This, however, along with jumping in cold water to test your choice of protective clothing, is inherently dangerous.
CONCLUSION

The main objective in paddle sports is to stay safe. For the informed and responsible paddler on cold water, acceptance of the issues of cold shock means dressing appropriately, maintaining your skills and avoiding cold water immersion to keep from drowning in the short term and warding off hypothermia in the long term. Grandpa, an old Navy man, used to say, “Water (the sea) simply waits for the innocent but actually stalks the unprepared, the careless and the arrogant.”

ADDENDUM: ADDITIONAL COLD WATER AND ASSOCIATED INFORMATION

* Statistically, canoe or kayak capsize occurs equally on calm or rough water. (6)
* Cold water removes heat from the body 25 - 30 times faster than cold air - much from the head and neck. (1) (7) (
* Physical activity in cold water increases heat loss. (6)
* Alaska has 10 X the national boating fatality rate. (9)
* More than 50% of fatal boating accidents (PA) occur in cold water, often fair weather, close to shore. (6)
* The killing factor is often that first shock of cold water on the body. (
* Strong swimmers wearing a PFD have died before covering 100 yards in cold water. (14)
* In water < 40* F, a strong man can expire before swimming 100 feet. (14)
* An average person has a 50/50 chance of surviving a 50 yard swim in 50* F water. (13)
* A 50 year old person in 50* F water has a 50/50 chance of surviving 50 minutes. (13)
* An unclothed person in 34* F water will maintain core temperature for 20 - 30 minutes. (1)
* Of 130 drownings in Canada in 2004 (16)
- 60% drowned in water under 10* C (50* F)
- 34% drowned in water between 10* - 20* C (50* - 68* F)
- 48% were in a boat that capsized or was swamped
- 43% were less than 2 meters from shore/safety (shore, boat, dock, etc)
- 66% were less than 15 meters from shore/safety
- Only 12% were properly wearing a lifejacket
* Of 524 fatal boating accident drownings in the US in 2002 (17)
- Nearly 85% of the victims were not wearing a PFD meaning 440 lives could have been saved if boaters had worn a lifejacket
- Over 48% (254 of 524 total) drownings occurred in boats less than 16'
- Canoes/kayaks were the 2nd most common type of boat involved in drowning incidents (1st type was open motorboat)
* Of 710 boating related deaths in 2006, the USCG reports 9 out of 10 persons were not wearing a PFD (1
* "Wear a Lifejacket" (19)
- People tend to drown in silence and without attracting attention.
- The struggle to breathe and stay afloat rarely enables them to wave their arms or call for help.
- 75% of boating fatalities could have been prevented if the victim were wearing a lifejacket.
* In Washington State, kayakers had the highest use (87%) of wearing a PFD, while motorboats had the lowest use (21%). (20)
* "In 2007, 107 fatalities were attributable to canoes, kayaks and rowboats. The use of properly fitted lifejackets could have prevented nearly all those fatalities." (21)



REFERENCES

(1) “Cold Water Survival”, www.acanet.org/safety
(2) “Baby It’s Cold Outside (believe it or not)”, Pennsylvania Fish & Boat Commission, Apr 21, 2005, www.sites.state.pa.us
(3) www.atlantickayaktours.com/pages/expertcenter/cold water
(4) Sea Kayak Chesapeake Bay, www.seakayak.ws
(5) “Cold - a Factor in Water Deaths”, www.wainwrighth.army.mil/safety/winter
(6) “Critical Judgment II”, American Canoe Association, Understanding and Predicting Canoe and Kayak Fatalities 1996 - 2002, 2004.
(7) “Cold Water Immersion”, Alaska Sea Kayaking Symposium, www.aksks.org
( Workers Compensation Board of BC, WS04-01, www.worksafebc.com
(9) “Cold Injuries Guidelines”, Version 2003, State of Alaska, www.chems.alaska.gov
(10) www.americanboating.org/hypothermia
(11) “Immersion in Cold water and Hypothermia”, J Tsung, MD, www.nykayak.com
(12) “Off Season Boating, Cold Shock and Hypothermia”, www.enter.net/~skimmer/
coldwater.html
(13) “Safety On (and in) the Water”, www.capital.net/com/nckayak/nck_safety_p4.html
(14) “Hypothermia and Cold Shock”, P Siedel, USCG Aux, www.auxguidanceskills.info/press/hypothermia.html
(15) www.hendersonusa.com, www.seattlefabrics.com
(16) www.coldwaterbootcamp.com/pages/1_10_60v2.html
(17) www.uscgboating.org/statistics/boating_statistics_2002.pdf
(1 www.cdc.gov/HomeandRecreationalSafety/Water-Safety/waterinjuries- factsheet.htm
(19) www.drowning-prevention.org/drowning_fact_sheet.pdf
(20) www.drowning-prevention.org/pdf/obs_2000.pdf
(21) www.commanderbob.com/canoes.html

Rev 03/06/09

[Peter & Judy]

Canadian Professor Dr. Gordon Giesbrecht (aka Dr. Popsicle) has done extensive research on cold water survival. The following video explains what do do if you fall through the ice and also has some relevant information that might help with cold water survival.

https://www.youtube.com/watch?v=Wz3gy5XyaBo

Dr. Popsicle has used himself in multiple cold water experiments and I'm not sure if he has children or not.

[RobLL]

At the longer USCG classes I took here in Puget Sound country the consensus from instructors is than should someone fall overboard it may be well to declare an emergency and call for help. Simply recovering the overboard person may not solve the emergency.

A main lesson which cannot be over emphasized: Do not fall overboard!

[JamesTXSD]

I may have mentioned this here before: a few years ago, one of the boats I drive was hired as a water taxi. Sitting at the dock on Lopez Island, waiting for the next load of passengers, we had about 20 minutes to kill - I went over safety procedures with the first mate, including man-overboard procedures.

About 30 seconds after that discussion, I heard a splash and a muffled cry. Looking behind us, someone had fallen off the large yacht back there! We got to the guy within 30 seconds, and with the cold and the shock, he was unable to lift his arms to aid in his rescue. It took 3 of us to get him back up on the dock.

I would guess he was in his 60s; physically fit. He reached into his dinghy that was hanging on the back on davits, lost his footing and fell in. That's how fast things can so south. He was OK, but had to be helped into his boat to get warmed up. There was no one else on his boat.

---------------

Working in the Tetons, where the water temp on Jackson Lake stays in the upper 40s to low 50s during most of the summer, when not driving the cruise boats, the captains rotated on driving the rescue boat. Most of the people I pulled out of the water were young - they thought it would be "refreshing" to get out of the rental kayaks and then were not physically able to get themselves back in. Or, got sideways to waves (in a canoe) when the occasional afternoon thunderstorm blew in.

There is a small "beach" (mostly rocky area) just north of the Colter Bay Marina, called Swim Beach. The water is shallow, so it does warm up more than the rest of the lake. It is known by another name to employees: Scream Beach... so named because people run into the water, then scream when they discover the warmer water is only the top 6 inches or so.

------------

The PNW can be a harsh water environment, especially that cold water when you go into it as a surprise. I've seen some tough folks intentionally jump in, but they don't stay in long. Well, unless you make it up to Desolation Sound, where the water temp is over 20º warmer.

[Peter & Judy]

I was kayaking yesterday here in the foothills of the Alberta Rockies on a small lake near my ranch. The ice has just come off the lake, so it is barely above freezing, a strong wind was blowing and there was reasonable chop on the lake. We dressed in our dry suits, even though the air was quite warm. It would have been more comfortable with less clothing on and of course we had our PFD's on. There was only two other boats on the lake, a canoe with two young men fishing and a small Lund with an out board. Typical of what I see is that the woman in the Lund had her PFD on and the 'Macho Men' in the Lund and the canoe had there PFD's in the boat, but not on their bodies.

Last winter I took my PFD to our nice warm indoor pool, threw the vest into the water, jumped in and tried to put it on. It is amazing how much effort it took to accomplish that task. In near freezing water when cold shock hits you it might be near impossible.

A year or two ago I heard the statistics of drowning victims in Canada, where we have lots of cold water. As I recall about 80% of the victims were adult males. Many, by the way had their flies undone.

[Karl]

Several manufacturers offer insulated work suits with flotation...jumpsuit style,
with a USCG rating.

Those suits will delay the initial cold shock, and extend hypothermia time.

I have only been in water as low as 55°F, and it was not pleasant.

Consider tethering yourself, with a quick-release harness, when boating in cold water...swimming with a PFD is awkward and slow, and you may not be able to reach your boat, or even climb the ladder if you can...

And, NEVER piss over the side...

[Peter & Judy]

I have jumped into water off of Ice flows into lakes that had a glacier in one end of it and I survived, but I was much younger then and would not consider doing this today, on purpose. The shock literally takes your breath away and it takes a while before you determine which way is out.

As a sea kayaker and canoeist, I have learned to dress for the water and not the air. On a motor boat some consideration must be given to doing the same. But, I think that you need to consider the conditions and the risk of going into the water. In bad weather, dressing with consideration that you may have to abandon ship is prudent. Cold water is just a fact of life here in Canada. I will be kayaking tomorrow in a lake that has just lost its ice cover, so the water will be near freezing, but the air temperature will be 27C (80F) which is a very hot day here in Alberta. But I plan to wear a wet suit in case I go for a swim.

Better to be safe than sorry.