Cold Water Survival (Hypothermia)

I posted this on Coastside and i think it is also worth noting here.

Here is the link to the information:  http://www.ussartf.org/cold_water_survival.htm



United States

Search and Rescue Task Force

Cold  Water  Survival

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Cold Water

What is it?  It is difficult even for an expert to define.  It is estimated to be around and under the temperature of 70 degrees.  However, this will vary in each case due to the specific circumstances and physical condition of the person involved.

What Happens In Cold Water?

Many of the fatal boating accidents occur in the "out-of-season" months when the water is cold.  What happens to the body when suddenly plunged into cold water?

The first hazards to contend with are panic and shock.  The initial shock can place severe strain on the body, producing instant cardiac arrest, as happened to a 15 year old scout in the month of March in Pennsylvania several years ago.

Survivors of cold water accidents have reported the breath driven from them on first impact with the water.   Should your face be in the water during that first involuntary gasp for breath, it may well be water rather than air.  Total disorientation may occur after cold water immersion.  Persons have reported "thrashing helplessly in the water" for thirty seconds or more until they were able to get their bearings.

Immersion in cold water can quickly numb the extremities to the point of uselessness.  Cold hands cannot fasten the straps of a lifejacket, grasp a thrown rescue line, or hold onto an over-turned boat.   Within minutes, severe pain clouds rational thought.  And, finally, hypothermia (exposure) sets in, and without rescue and proper first aid treatment, unconsciousness and death.  We all recall the incident in which the airliner went down in the dead of winter in the water in Washington, D.C. several years ago.  The vivid video of the rescue attempts and those that died due to hypothermia is not easily forgotten.

Normal body temperature of course, is 98.6.  Shivering and the sensation of cold can begin when the body temperature lowers to approximately 96.5.  Amnesia can begin to set in at approximately 94, unconsciousness at 86 and death at approximately 79 degrees.

What To Do In The Water

Cold water robs the body's heat 32 times faster than cold air.  If you should fall into the water, all efforts should be given to getting out of the water by the fastest means possible.

Persons boating in the cold water months should be thoroughly skilled in rescue and self-rescue techniques.  Most accidents involve small boats which with practice, can be righted and re-entered.   Most boats, even filled with water, will support the weight of its occupants.   If the boat has capsized and cannot be made right, climb on top of it.

Physical exercise such as swimming causes the body to lose heat at a much faster rate than remaining still in the water.  Blood is pumped to the extremities and quickly cooled.  Few people can swim a mile in fifty degree water.  Should you find yourself in cold water and are not able to get out, you will be faced with a critical choice - to adopt a defensive posture in the water to conserve heat and wait for rescue, or attempt to swim to safety.

Should you find yourself in the water, avoid panic.  Air trapped in clothing can provide buoyancy as long as you remain still in the water.  Swimming or treading water will greatly increase heat loss and can shorten survival time by more than 50%.

The major body heat loss areas are the head, neck, armpits, chest and groin.  If you are not alone, huddle together or in a group facing each other to maintain body heat.

Preparation

Proper preparation is essential when boating on cold water.  Make sure your boat and equipment are in first class condition.  Check the weather forecast before leaving for your event.   Always tell someone where you are going and when you expect to return.  Dress in several layers of light clothing.  Next to a diver's wet suit, wool clothing offers the best protection.  Always wear a personal flotation device (PFD) when boating.

First Aid Considerations For Cold Water Victims

Treatment for hypothermia depends on the condition of the person.  Mild hypothermia victims who show only symptoms of shivering and are capable of rational conversation may only require removal of wet clothes and replacement with dry clothes or blankets.

In more severe cases where the victim is semi-conscious, immediate steps must be taken to begin the rewarming process. 

Get the person out of the water and into a warm environment.  Remove the clothing only if it can be done with a minimum of movement of the victim's body.  Do not massage the extremities.

Lay the semi-conscious person face up, with the head slightly lowered, unless vomiting occurs.  The head down position allows more blood to flow to the brain.

If advanced rescue equipment is available it can be administered by those trained in its use.  Warm humidified oxygen should be administered by face mask.

Immediately attempt to rewarm the victims body core.  If available, place the person in a bath of hot water at a temperature of 105 to 110 degrees.  It is important that the victim's arms and legs be kept out of the water to prevent "after-drop".  After-drop occurs when the cold blood from the limbs is forced back into the body resulting in further lowering of the core temperature.  After-drop can be fatal.

If a tub is not available, apply hot, wet towels or blankets to the victim's head, neck, chest, groin, and abdomen.   Do not warm the arms or legs.

If nothing else is available, a rescuer may use their own body heat to warm a hypothermia victim.

Never give alcohol to a hypothermia victim.

Some Important Facts To Remember

Most persons recovered in cold water "near" drowning cases show the typical symptoms of death:

    *

      Cyanotic (blue) skin coloration
    *

      No detectable breathing
    *

      No apparent pulse or heartbeat
    *

      Pupils fully dilated (opened)

These symptoms, it was discovered, did not always mean the victim was dead.  They were, on the other hand, the body's way of increasing its chances of survival through what scientists call the mammalian diving reflex.  This reflex is most evident in marine mammals such as whales, seals or porpoises.  In the diving reflex, blood is diverted away from the arms and legs to circulate (at the rate of only 6-8 beats per minute, in some cases) between the heart, brain and lungs.  Marine mammals have developed this ability to the point where they can remain under water for extended periods of time (over 30 minutes in some species) without brain or body damage.

Humans experience the diving reflex, but it is not as pronounced as in other mammals.  The factors which enhance the diving reflex in humans are:

    *

      Water temperature - less than 70 degrees or colder, the more profound the response and perhaps the more protective to the brain
    *

      Age - the younger the victim, the more active the reflex
    *

      Facial immersion - the pathways necessary for stimulating this series of responses seem to emanate from facial cold water stimulation.

The diving reflex is a protective mechanism for humans in cold water immersions, but it may confuse the rescuer into thinking the victim is dead.  Resuscitative efforts for these victims should be started immediately utilizing CPR in accordance with your training.

Remember, numerous children have been brought up from freezing water after 30 minutes and been successfully resuscitated.

Expected Survival Time in Cold Water

Water Temperature
   

Exhaustion or Unconsciousness in
   

Expected Survival Time

70–80° F (21–27° C)
   

3–12 hours
   

3 hours – indefinitely

60–70° F (16–21° C)
   

2–7 hours
   

2–40 hours

50–60° F (10–16° C)
   

1–2 hours
   

1–6 hours

40–50° F (4–10° C)
   

30–60 minutes
   

1–3 hours

32.5–40° F (0–4° C)
   

15–30 minutes
   

30–90 minutes

<32° F (<0° C)
   

Under 15 minutes
   

Under 15–45 minutes

Water skier line

                                                   

What a great article. Thanks for posting that Isda.

The timeline to unconsciousness in 50* water seems a little optimistic no?

Is this with or without a dry suit

If nothing else is available, a rescuer may use their own body heat to warm a hypothermia victim.

Pee on em??

Pee on em??

Just not after eating asparagus or drinking Pabst 

Great article, thanks for posting it up.

Is this with or without a dry suit

Duane,

I'm sure the drysuit buys you some time but eventually you will get tired and begin to succumb to the temperature.  I think most of us kayak with others and that is a safety factor that we must not take for granted.  Hookups can save your life one day.  On that note where have you been?  I haven't seen any posts from you. 

I still owe you a ride from like 2 years ago so let me know when you want to run for Halibut or Salmon.

Luis

Is this with or without a dry suit

I'm sure the drysuit buys you some time but eventually you will get tired and begin to succumb to the temperature.  I think most of us kayak with others and that is a safety factor that we must not take for granted. 

Yes, nothing takes the place of other people there to help you—nothing. However a dry suit buys you many hours. I have flopped around for several hours doing sea kayak rescue drills in water temps I would have been shaking in in 30 minutes in a 3 mil wet suit. Divers in dry suits dive for a long time in water than would  kill them in a wet suit in minutes. the hard part is you have to wear sufficient insulation under the thin Gore-tex dry suit to keep you warm and that means you sometimes sweat when out of the water where the air temp is often well above the water temp you need to insulate for. It's an expensive but very reliable and significant lifesaver.

I have extensive experience with hypothermia having spent my youth surfing the atlantic. We started surfing around 7 years old and all we had  were wetsuit tops that were hand me downs from older larger brothers. They were loose fitting and did not keep us warm in the least. We experienced hypothermia on a regular basis. Water temps we surfed in with these useless wetsuit tops were mid 50's. We were able to stay in the water for a little over an hour. AT that point what occurs is you stop moving. One of our friends was made of bones. Not a drop of fat on him and he would always start to freeze first. What happens is you just start to sit there not moving, you get lethargic and, just sit there shivering. Our lips and fingers would turn blue and we would shake uncontrollably for a bit till we warmed up. We froze like this regularly, I believe That is about the limit a human can withstand. That would be mild hypothermia. That's all we could take.

I also surfed atlantic winters late 70's with a 3/16 Oneill Super Suit(wetsuit). Air temps often in the 20's, water temps freezing and below, we had to coat our faces with vaseline to keep from getting frost bite. You get held under, ice cold water goes down your back and even with an Oneil; Super Suit designed for this that cold water coming in would suck your breath away and often you are surfacing hyper ventilating. Often I would experience rapid breathing. Starting in march we would sometimes take off our hoods. Water temps would be in the low 40's in march. When you get held under you get a wicked ice cream headache and come up hyperventilating.

I surfed a winter so cal @ SB with just a vest when I was 18. water temps around 55 or so. I was able to surf for about a little over an hour. That would be the same water temps as when I was a kid.
Now this is not constant immersion. I was sitting on a surfboard paddling and charging hard burning calories and generating warmth. When I wipe out I just climb back on the board.
I would say that an hour of immersion up to your chin in 50 degree water will bring most folks close to death. Good article very accurate.

I have a Stohlquist bpod drysuit. I have had it for 2 winters now. I paddle/flyfish half frozen lakes in the CA sierra's all winter long often in blizzards(actually it is warmer when it is snowing). I get in the water in the dead of winter and swim and float around testing the suit regularly. I just enjoy being in the water. I just like to swim and float around in my pfd so I enjoy being in the water even when it is icy cold. Plus this prepares me for an extended immersion. It's dry, not a drop of water gets in. I wear a 7mm dive hood and gloves. I wear some wicking underwear and then expedition weight fleece pants and shirts, 2 pairs of socks etc. I highly recommend this suit. I got one for a little over $500. Worth every penny. It breathes great. When it gets too hot out I just wear wicking under wear which is warm enough for a fairly lengthy immersion when water temps are in the 50's. I highly recommend this suit.
http://www.stohlquist.com/index.php?option=com_content&view=article&id=40&Itemid=20#1

At GS5 five you could have tossed a rock into the launch area and it would have bounced of 5 ppl with....MAN IT WAS FREEZING OTW!

Last saturday was the only time in the last five years that I drove over the hill to Santa Cruz, showed up to swim open water, and did NOT get in.  Porky agreed to pilot me for 1-2 mile swim out of Cap Wharf over to Pleasure Point and back.  Weather buoy reported 53 degree surface temp.  When I got to his house, there was a biting wind.  I totally pussed out.  Even more important than getting open water yardage was the need to avoid getting sick. 

Of course, this Saturday, I'll have no choice but to git 'er done because I'm racing at Aquathlon Nationals in Longmont, Colorado.  Race organizers said water is in the low sixties, but I'm calling BS on that.  Denver is reporting thunderstorms all week with air temps into the low forties at night.  thankfully its only a 1.5K (0.97 mi) swim.  I should finish the swim in about 22-23 mins, depending on how badly I'm sucking air at that altitude. 

I think we'll be lucky to see 56-58 water surface temps.  That cold water is going to make for a very interesting (read: slow) transition, and one helluva cold morning run