warm water hypothermia

[Kaffphine]

Blacknet, not having any medical training on the subject I can't give you information on the physiology. However from personal expericence I can tell you it does exists. Before story-time let me first amidt to being a BIG wuz when it comes to cold. Carribean summer, if anyone else was wearing a wetsuit it was a 2 or 3 shortie... I had my 4mm farmer john, both pieces. That's what I needed to stay warm. I also spend a lot of time in the water, as my job required it. So the idea of even warm water dropping your core temp over time, at least in my expericenes, is true. There was one night dive, two tank 40-50ft, where after I just could not get warm. Another night dive, where as a joke on me always being cold at night, someone brought a jug of hot water... for the second dive, I used it!

If your intersted/concern on the subject is for a trip to warm water.... I found two things that work for me. Either keep the wet suit on for awhile after you surface, movement always helps. Or get out of as quick as possible and into pants & a shirt.


BTW, just so there isn't a lot of posts in regard to me being too much of a cold water wuz. Is the first thing I did up here get into a dry suit, YES. Am I a wuz when it comes to cold, YES. Can I shut up and take it, YES!!

 

[Aquamore]

Uncle Pug

Don't miss thisopportunity, Go Ice Diving)

Aquamore

 

[TwoBitTxn]

Originally posted by Kaffphine
If your intersted/concern on the subject is for a trip to warm water.... I found two things that work for me. Either keep the wet suit on for awhile after you surface, movement always helps. Or get out of as quick as possible and into pants & a shirt.

Jess,


Leaving the wet suit on will actually continue to cool the body. The evaporation of water off the suit causes the body to continue cooling. Your second idea of getting out of the suit and into something dry will aid the body in warming up the fastest.

Tom

 

[Kaffphine]

Tom Vyles-

"Leaving the wet suit on will actually continue to cool the body. The evaporation of water off the suit causes the body to continue cooling. "


Just what worked for me (when the sun's up).

 

[Walter]

Sorry OD,

A couple of errors that need clearing up.

"Any time a body is in an environment that is colder than 98.6 F, heat is lost."

Not exactly true. Our bodies produce heat and we need to lose some of it. Our bodies actually maintain our ideal temperature better when the environment is cooler than "body temperature."

"heat is lost to water conduction 240 times faster than to air"

I believe you slipped a decimal, isn't it 24 rather that 240?

DSSW,

WWW™

 

[Ontario Diver]

Walter,I pulled out my reference ... (BTW it is Hypothermia, Frostbite and Other Cold Injuries by Wilkerson, Bangs, and Hayard - Mountaineering Press)

It states the 240 X conductivity for water versus air, which isn't quite the same thing as rate of body cooling. (I think that I remember something in the PADI class that said something about the body cooling in water 20 times faster) One of the problems is that we lose heat mostly through radiation and then through convection (good 'ol Wind chill). When immersed in water, conduction (which is much more efficient - ;-0 ) is the culprit. Other problem with water is that it absorbs far more heat than air. Human bodies actually have a small amount of warm air surrounding thier body that acts as an insulator. (this can be distrubed by wind, which is why you feel colder in the wind). Remember that this is for bare skin immersion, not with exposure protection.

As for the other point, we are both right. Your body does lose heat to the environment continually and (as you pointed out) it is "engineered" to do exactly that. Hypothermia sets in when the rate of heat loss exceeds body heat production.

Hope that this clears things up.

Matt

 

[The Iceni]

"Leaving the wet suit on will actually continue to cool the body. The evaporation of water off the suit causes the body to continue cooling. "

I am not really sure about this.

In the UK we tend to use dry suits, or semi-dry suits. The latter are basically a wet suit with neck, wrist and arm seals.

If I had to care for such a casualty on a small boat or RIB on the North Sea I think I would leave his wet suit on, but dry the outside and cover him with additional warm clothing.

There will be little, if any, evaporation, between the skin and the suit, just a layer of water and air saturated with water vapour at skin temperature. The insulation of the neoprene will stiil be present and any evaporative cooling from the surface of the wetsuit can be stopped by drying and adding further protective layers, to protect from "wind chill factor".

The problem that I face if I take off the victim's wetsuit is what do I replace it with?

Granted a good warm DRY sleeping bag would be ideal but how do I keep it dry and am I likely to have one in any case? It would most certainly be a thermal shock to remove the wetsuit and expose his body to the elements, even for a short time.

As for warm water hypothermia?

I believe there is still recognised to be considerable differences bewteen the features and the treatment of rapid onset hypothermia and insidious (slow onset) hypothermia, to which I assume you are referring

The former, such as immersion in the winter sea, is rapid and rapidly fatal. It is also possible, rapidly, to reverse it.

Slow onset hypothermia, such as is seen on the moors, on boats at sea and presumably long periods of immersion in cool water, is much more problematic and difficult to treat because the victims tend to be dehydrated and exhausted and to have developed multi system failure.

I would remove the casualty from the source of heat loss, keep them horizontal, rehydrate them with warm sweet fluids and keep them warm and dry.

I won't pretend I know any more.

 

[devjr]

Recently, on a typical sunny, late October day near Bimini I was in the water for four hours. No suit was worn, just trunks and freediving gear. Later that day, wearing a nylon skin, I made a tank dive which lasted 45 minutes. At the end of the dive I felt chilled, and upon boarding immediately shed the skin and dried off while stowing my gear. No big deal, nothing there to "study", just another day.

 

[The Iceni]

You felt cold.

I suggest that would be expected as you had been cooling your body both during your four hour stint in the sea and later when diving but, Devjr, I do not think you suffered from hypothermia.

I think it is very important to differentiaite between hypothermia and the body's natural reaction to cold.

Like any other environmental stress on the body, when heat loss increases for whatever reason, the body reacts to it. While there are many reflex reactions, such as peripheral vasocontriction, the erection of body hairs and an increased rate of energy production from the liver, the brain also tells you it is unhappy; you experience discomfort and therefore take appropriate action, such as putting your coat and hat back on!

If this is not sufficient to redress the thermal balance and your core temperature further drops below a trigger temperature, involuntary shivering starts, since the muscles are a powerful source of heat energy. In all likelihood the body's temperature then returns to normal, shivering stops and you feel much better.

Unfortunately this also occurs if these are insufficient to correct the heat loss and your body temperature continues to fall, this is particularly the case once the liver's energy-producing glycogen stores are exhausted.

This is hypothermia.

As far as you can tell from the inside you are fine and may even feel euphoric. Clearly this is extremely dangerous because all your defences have been deployed to no avail, there is little more your body itself can do and your core temperature continues to fall. In addition, although it may be apparent to others, you are entirely unaware of the extreme danger you are in.

Hypothermia is a very dangerous medical condition. It is a killer. The vast majority of deaths in the Atlantic from shipwreck are not from drowning, as with the Titanic they are from hypothermia.

As far as I am aware, there is no generally accepted subset of hypothermia attributed to "warm water".

Hope that helps your confusion, Devjr.

 

[devjr]

Manifestly, we can thank Dr. Mengele for many of our experimental data on humans. No offense, Dr. Paul, I appreciate the lengthy and orderly dissertation, and I'm sure you acquired this information in a more conventional way. To me it tends to frame the warm water issue as a strawman, which it probably is, at least for all but academic purposes. I might add to your comments that hypothermia victims have reported a feeling of warmth in the final moments. Rereading your remarks, you implied as much if not specifically.

About wet suits, I have to confirm that topside exposure to a chill wind is pretty tough on a wet diver. The only solutions are removal of the suit and donning some clothing, or pouring hot water down the neck of the suit. However, returning from a dive in the thermocline to greet a hot summer day will not unduly chill the diver who keeps his suit on.