Body core temperature and Diving

[Remy B.]

Like in many SB posts the OP starts with one questions and the thread ends talking about what oil you use for you car motor.

But then some more questions come out of these derails of conversations and opinions, and this one ended in cold tolerance and DCS

DCS and diving cold, but where does lay the border, as some persons are more susceptible than others to cold.

Like everybody knows cold blood and tissues Off-gas inefficiently.

But one thing is having cold hand and feet maybe ears, but your core temperature is not affected as of, you don't feel cold, no shivering, not cold skin, no cold arms or legs, you come out the water feeling normal.

 

[w3dge]

I guess a question that comes up is; When someone is more tolerant to cold, is it that they truly don't get cold as easily, or they are able to endure being colder than others?

 

[PfcAJ]

If you have cold hands feet and ears your core temp is for sure affected.

Getting cold on deco isn't great, but the question that I don't think anyone has a good answer to is how cold=how much change in DCS risk.

 

[Diver0001]

Dr, Powell was always pretty clear that getting cold during deco isn't good.

As PfcAJ pointed out, however, there's no good recipe to adjust the algorithm. The rules for the PADI RDP suggest planning the NDL for the dive as if the dive were 4 meters deeper in cold conditions. With broad brush strokes you can see that as more or less cutting the available NDL in half. That's about as close as we have to any statement of what to do.

If you're decompression diving in cold conditions, therefore, you could look for a setting on your computer that increases the amount of deco by some ratio of the amount of time that would have been required if the dive were 4 meters deeper. You might be able to do that with fiddling with the GF-hi.

That too would be like trying to do surgery in the dark but by lowering the GF-hi it might not help, but it probably won't hurt.

What I personally do, which is not a recommendation and I may be crazy for doing this, is to no adjust my deco time at all but to cut the bottom time back so I don't get cold enough that I'm starting to shiver.

So far, so good, but that's a sample size of one and not a good indication of expectations of success in the big picture.

R..

 

[Remy B.]

Having cold hands and feet, seems to me logical but not related that much of core temperature because does are the body parts with less flesh and blood circulation so the water temp will affect them first, if one start to shiver that is a indication that your core temperature has been compromised, you shall never get to that point, probably not the right amount of thermal protection.


I believe there was a test from NEDU not so long ago, where they exposed the divers to cold conditions as part of many tests, but I'm not sure what exactly they were testing in the chamber becasue there was different tests.

 

[Remy B.]

I guess a question that comes up is; When someone is more tolerant to cold, is it that they truly don't get cold as easily, or they are able to endure being colder than others?

At least for me I don't get cold easy ( core temp ), and I don't tolerate cold hands as it is painful.

I grewup in South America, I was not able to sleep without AC, I go to sweat to a point that the bed sheets are soaked.

I worked in siberia, and used less thermal protection than the locals, less to no heating to sleep, actually the people cleaning the living quarters were complaining when they enter my room because it was too cold ( to their standards )

So far my feet are warm I'm a happy camper.

I start with good protection when I sleep, but in the middle of the nights I wake up due to the heat and have to take out some layers off, and continue sleeping I don't get cold again because I have less thermal protection, but I assume this is a normal thing as all persons have auto compensating core temperatures up to a point of course, because it is not that I don't get cold it all, it is that it takes more time to get to that point comparing it with others.

 

[Diver0001]

I believe there was a test from NEDU not so long ago, where they exposed the divers to cold conditions as part of many tests, but I'm not sure what exactly they were testing in the chamber becasue there was different tests.

Now that you mention it I remember that paper. I think there was a very good presentation done on it which should be available on youtube.

Found the article: [abstract] WATER TEMPERATURES FOR MATCHED COLD EXPOSURES IN DIVERS WITH OR WITHOUT WET SUITS DURING AIR DECOMPRESSION DIVES.

Now to find the presentation. It was very good..... stand by

R..

 

[Diver0001]

Ok, found the video but I now see that the authors are not the same. The video was done at Duke. Still very interesting if you can get over the "lecture hall" feeling of it. Only part of it is about thermal stress but what he is saying is summarizing the work done at NEDU and explained in the article I linked.

 

[USMC CPL.]

I guess a question that comes up is; When someone is more tolerant to cold, is it that they truly don't get cold as easily, or they are able to endure being colder than others?

I guess I am one of those people that tolerate the cold. I dive in a 3 mil wetsuit in water temps low 50's and always feel fine.

 

[dreamdive]

The Rebreather Exploration and Research Organization

In the Reference Library, go to page 39 for various articles