5 ms·

A very good article that shows some perceived misconceptions about cold water survival. I spent 4 years on 20 different large marine seismic exploration boats w

by TGJ 16y ago

A very good article that shows some perceived misconceptions about cold water survival. I spent 4 years on 20 different large marine seismic exploration boats with most of them operating in the North Sea. I have taken 3 North Sea Survival courses and a many safety meetings for good measure. Every person that I have worked with has been well aware of the consequences of falling overboard in water barely above freezing. Larger boats take at least an hour to turn around and at least 10-15 min for the rescue boat to hit the water. Then, only if your lucky, will they be able to find you as you bob in and out of view from the waves. All of this of course, relies on someone seeing you fall over in the first place. Never work on deck unless you are working with someone, have an immersion suit, or are attached by a safety chain. Another problem arises when you are rescued as he points out, but the stories I have heard are about the survivors being put in showers to raise their body temperature back up and collapsing and drowning in a puddle of water in the shower. The whole thing, on the other hand, seems fairly moot. It's like telling someone that when you get shot, it's not the bullet that kills you, it's the bleeding.

sliverstorm 16y ago
> Another problem arises when you are rescued as he points out, but the stories I have heard are about the survivors being put in showers to raise their body temperature back up and collapsing and drowning in a puddle of water in the shower. This problem shouldn't even be a problem, you shouldn't leave them alone when they are recovering! Well, IMHO.
- brazzy 16y ago
  It's still a problem, because raising the body temperature quickly can be dangerous in itself. To preserve core temperature, the body centralizes circulation, i.e. circulates blood only through the vital organs. If you're warmed up suddenly, it can cause this centralization to end prematurely, mixing still-too-cold blood from your extremities with the core blood and dropping your core temperature suddenly and fatally.
  - niels_olson 16y ago
    > mixing still-too-cold blood from your extremities with the core blood and dropping your core temperature suddenly and fatally. Unlikely. there will be very little of that cold blood to mix. Very little. Adding heat will cause your core temperature rise. What is more likely to happen is that the sudden vasodilation drops your blood pressure, and your heart, possibly still in it's stunned cold state, can't compensate with stroke rate or variability. Then you risk cerebral hypoperfusion in the face of increasing metabolic demand (warm cells run faster, burn more glucose, need more oxygen to burn that glucose)
  - rm-rf 16y ago
    I had something like this happen - except for the 'fatally' part of course. I was in a canoe race on a cold spring day in cold water. At the beginning of the race I ended up jumping into the river in waste deep water. My jeans stayed wet the whole race. My legs were cold wet and immobile for over an hour while my upper body was 'working out' paddling the canoe. All was good until the race ended. I got out of the canoe to walk the 1/2 mile back home. As soon as I started walking I felt the cold blood from my legs rush up to my torso & started seriously shivering. Continuing to walk made it worse. Made it home anyway & collapsed under a hot shower. I felt at the time that if I'd have tried to walk much further I'd have had a real bad day.
drats 16y ago
I particularly like the tone in "I know that you think you know all there is to know about hypothermia already (and maybe you do), but read ahead and see if you aren’t surprised by something" given that someone actually downvoted me when I took exception to the line "whatever you just said, it's wrong" in the "Where Does A Tree Get Its Mass?" article[1] when it was posted to HN. There is no need for all the hyperbole and Zed Shaw-like drama on HN, articles can be interestingly written without all that baggage. That someone such as yourself, who knows a lot about this, and someone like me who doesn't can both enjoy the article is a testament to the style. [1]http://thelastpsychiatrist.com/2008/11/where_does_a_tree_get_its_mass.html http://thelastpsychiatrist.com/2008/11/where_does_a_tree_get...
- ErrantX 16y ago
  You should have read on; it was just an attention grabber :)
  - drats 16y ago
    I don't want to offend anyone but that article was extremely boring (I did end up reading it). I suppose I'd seen the Richard Feynman video on fire and trees quite recently beforehand and was in an intolerant mood. But it's impossible to stay in any kind of negative mood if you watch Feynman, his love of knowledge is just infectious. http://www.youtube.com/watch?v=N1pIYI5JQLE http://www.youtube.com/watch?v=N1pIYI5JQLE
- ra 16y ago
  "Zed Shaw-like drama" :-)
hackermom 16y ago
In maritime navigation class, we were taught that artificially heating a person who has been chilled down (that is, heating by giving them something warm to drink, putting them in a hot shower etc.) sometimes result in something very similar to a cold shock response, a sort of "hot shock response" known to cause severe after-effects and apparently even death. Tests carried out by the Swedish Sea Rescue Society along with data from over one hundred years of recorded incidents, showed that the safest way to sustain a person suffering a cold shock or near hypothermia is to simply uncloth them (if soaked in water), blanket them lightly, and let their body heat itself up to normal temperature, utilizing the time in parallel to make sure heart rate and blood pressure stabilizes in calm tempo.
gaius 16y ago
The best way to warm someone up with hypothermia is for someone to get into a sleeping bag with them. I've done the sea survival training for offshore racecrew and it's the same: you're in your suit, wearing a lifejacket and harness, and attached to a jackstay. There are radio tags you can get now, about the size of a matchbox, you wear one and if it goes out of range of the basestation a MOB alarm goes off. Clever, but at night, in rough seas, making 10 kts, you're still in a LOT of trouble.
- Alex3917 16y ago
  "The best way to warm someone up with hypothermia is for someone to get into a sleeping bag with them." Don't ever do this. The cold blood in their arms and legs will rush to their heart and kill them. You are supposed to leave them out in room temperature and wrap their core in blankets until the blood near their heart is able to reheat their limbs.
  - gaius 16y ago
    On a racing yacht at sea there is no "room temperature"!! Ambient temperature inside the hull might be slightly warmer than the sea, but barely. You can't even go into a cabin and close the door, because there are no cabins and doors, there're berths above stowage compartments or in the sail locker. Once you get cold and wet out there, you aren't going to get warm and dry again until the race is over and you're back on land, which might be days and hundreds of miles away. So we train for that. Similarly in our first aid, the "rules" on moving casualties are different. 'Cos you can't leave them on-deck...
    - Ixiaus 16y ago
      This is correct advice. Warming the person by hugging them inside of a sleeping bag is the best way to help. Now, rubbing them or massaging them is not a good idea because it does circulate the cold blood back to the core.

by TGJ 16y ago

sliverstorm 16y ago

> Another problem arises when you are rescued as he points out, but the stories I have heard are about the survivors being put in showers to raise their body temperature back up and collapsing and drowning in a puddle of water in the shower. This problem shouldn't even be a problem, you shouldn't leave them alone when they are recovering! Well, IMHO.

brazzy 16y ago
It's still a problem, because raising the body temperature quickly can be dangerous in itself. To preserve core temperature, the body centralizes circulation, i.e. circulates blood only through the vital organs. If you're warmed up suddenly, it can cause this centralization to end prematurely, mixing still-too-cold blood from your extremities with the core blood and dropping your core temperature suddenly and fatally.
- niels_olson 16y ago
  > mixing still-too-cold blood from your extremities with the core blood and dropping your core temperature suddenly and fatally. Unlikely. there will be very little of that cold blood to mix. Very little. Adding heat will cause your core temperature rise. What is more likely to happen is that the sudden vasodilation drops your blood pressure, and your heart, possibly still in it's stunned cold state, can't compensate with stroke rate or variability. Then you risk cerebral hypoperfusion in the face of increasing metabolic demand (warm cells run faster, burn more glucose, need more oxygen to burn that glucose)
- rm-rf 16y ago
  I had something like this happen - except for the 'fatally' part of course. I was in a canoe race on a cold spring day in cold water. At the beginning of the race I ended up jumping into the river in waste deep water. My jeans stayed wet the whole race. My legs were cold wet and immobile for over an hour while my upper body was 'working out' paddling the canoe. All was good until the race ended. I got out of the canoe to walk the 1/2 mile back home. As soon as I started walking I felt the cold blood from my legs rush up to my torso & started seriously shivering. Continuing to walk made it worse. Made it home anyway & collapsed under a hot shower. I felt at the time that if I'd have tried to walk much further I'd have had a real bad day.

drats 16y ago

I particularly like the tone in "I know that you think you know all there is to know about hypothermia already (and maybe you do), but read ahead and see if you aren’t surprised by something" given that someone actually downvoted me when I took exception to the line "whatever you just said, it's wrong" in the "Where Does A Tree Get Its Mass?" article[1] when it was posted to HN. There is no need for all the hyperbole and Zed Shaw-like drama on HN, articles can be interestingly written without all that baggage. That someone such as yourself, who knows a lot about this, and someone like me who doesn't can both enjoy the article is a testament to the style. [1]http://thelastpsychiatrist.com/2008/11/where_does_a_tree_get_its_mass.html http://thelastpsychiatrist.com/2008/11/where_does_a_tree_get...

ErrantX 16y ago
You should have read on; it was just an attention grabber :)
- drats 16y ago
  I don't want to offend anyone but that article was extremely boring (I did end up reading it). I suppose I'd seen the Richard Feynman video on fire and trees quite recently beforehand and was in an intolerant mood. But it's impossible to stay in any kind of negative mood if you watch Feynman, his love of knowledge is just infectious. http://www.youtube.com/watch?v=N1pIYI5JQLE http://www.youtube.com/watch?v=N1pIYI5JQLE
ra 16y ago
"Zed Shaw-like drama" :-)

hackermom 16y ago

In maritime navigation class, we were taught that artificially heating a person who has been chilled down (that is, heating by giving them something warm to drink, putting them in a hot shower etc.) sometimes result in something very similar to a cold shock response, a sort of "hot shock response" known to cause severe after-effects and apparently even death. Tests carried out by the Swedish Sea Rescue Society along with data from over one hundred years of recorded incidents, showed that the safest way to sustain a person suffering a cold shock or near hypothermia is to simply uncloth them (if soaked in water), blanket them lightly, and let their body heat itself up to normal temperature, utilizing the time in parallel to make sure heart rate and blood pressure stabilizes in calm tempo.

gaius 16y ago

The best way to warm someone up with hypothermia is for someone to get into a sleeping bag with them. I've done the sea survival training for offshore racecrew and it's the same: you're in your suit, wearing a lifejacket and harness, and attached to a jackstay. There are radio tags you can get now, about the size of a matchbox, you wear one and if it goes out of range of the basestation a MOB alarm goes off. Clever, but at night, in rough seas, making 10 kts, you're still in a LOT of trouble.

Alex3917 16y ago
"The best way to warm someone up with hypothermia is for someone to get into a sleeping bag with them." Don't ever do this. The cold blood in their arms and legs will rush to their heart and kill them. You are supposed to leave them out in room temperature and wrap their core in blankets until the blood near their heart is able to reheat their limbs.
- gaius 16y ago
  On a racing yacht at sea there is no "room temperature"!! Ambient temperature inside the hull might be slightly warmer than the sea, but barely. You can't even go into a cabin and close the door, because there are no cabins and doors, there're berths above stowage compartments or in the sail locker. Once you get cold and wet out there, you aren't going to get warm and dry again until the race is over and you're back on land, which might be days and hundreds of miles away. So we train for that. Similarly in our first aid, the "rules" on moving casualties are different. 'Cos you can't leave them on-deck...
  - Ixiaus 16y ago
    This is correct advice. Warming the person by hugging them inside of a sleeping bag is the best way to help. Now, rubbing them or massaging them is not a good idea because it does circulate the cold blood back to the core.