At what temperature does water have to be in order to cool the body to
33 degress Celsius within 30 minutes?

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Request for Question Clarification by wengland-ga on 07 Jun 2002 11:45 PDT

You'll need to define a couple of things first.  

1) Starting temperature of the body (Normal? Fevered? Dead?)

2) Mass of the body (weight in kilos)

Then we can anwer the question.

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Request for Question Clarification by blader-ga on 07 Jun 2002 12:00 PDT

Dear dgc:

As wengland pointed out, you will need to starting temperature and the
mass of the body. You will also need the specific heat capacity of the
body, and also the surface area of said body. We will also need to
know how much of the body is immersed in the liquid (half way?
completely?) Would you like general methods for calculations? Or would
you like an average number for an average body, under complete
submerged assumptions?

Best Regards,
blader-ga

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Clarification of Question by dgc-ga on 07 Jun 2002 12:50 PDT

Let's say normal starting temperature (98.6 F), 200-pound person,
completed submerged except for the head. I don't know about "specific
heat capacity" or "surface area." There, we'll have to go for
ballpark. If there is a calculation/equation, fine. If there is a
specific answer, that's good too. Please list your sources for
verification. Thank you.

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Request for Question Clarification by blader-ga on 07 Jun 2002 13:20 PDT

Dear dgc:

Sorry for the clarification requests, but it is a complicated
question. Can we assume that the temperature of the water is to be
maintained constant? That is, if we were to really submerge a body in
a body of water, the temperature of the water will increase over time.
If this is so, then this vastly complicates the calculations. If, on
the other hand, there was a cooling mechanism that maintains the water
at a constant temperature, this would make things a lot simpler.

Best Regards,
blader-ga

Hello  dgc-ga,

I finally did succeed in finding some real information on this topic. 
Going by the results of studies that have been carried out in humans,
the answer to your question is that the degree of cooling you wish
cannot be achieved in the time you state if you are considering
immersion with the head out of water and with no water being
swallowed.

An army manual on extreme conditions has a chapter on cold water
immersion, which can be accessed at:
http://www.armymedicine.army.mil/history/borden/medaspofharshenvrnmnts/ch17_cold/chpt17cold.htm

This states that “Observations in subjects undergoing head-out water
immersion (see Figure 17-4) show that even in very cold water (eg, 5
deg C), the rate of core temperature drop is only 0.06 deg C per
minute.”

Figure 17-4 (available at
http://www.armymedicine.army.mil/history/borden/medaspofharshenvrnmnts/ch17_cold/fig17-4.htm)
graphs the rate of core cooling as a function of water temperature
using data from 17 separate published reports mainly on young white
men of average build, fat content, and physical fitness. The subjects
were not wearing any clothing or employing any devices that were
designed to protect against cold exposure.

At 5 deg C with a cooling rate of 0.06 deg C per minute, you would
need, on average, something like 75 minutes to achieve the approx. 4.5
deg C drop in core body temperature that you require.

The manual does also state that core temperature decreases more
rapidly if water is swallowed.  However, no further details are given.
 Incidentally, the manual makes the point that “initial cold immersion
insult may result in death from drowning, cardiovascular collapse, or
both, but not from hypothermia.  If the initial entry into the cold
water is gradual (staged) or is a common occurrence for the individual
(eg, cold water swimmers and divers), then the cardiovascular and
respiratory changes may be significantly attenuated.”

I found the manual by searching on teoma.com, using the terms:
physics, hypothermia, water, body, temperature, equation

A paper published in March 1984 in the journal Aviation, Space and
Environmental Medicine, Vol 55: pp. 206-2 11  on “Physiological
responses and survival time prediction for humans in ice-water.” by JS
Hayward and JD Eckerson confirms this.  For the purpose of their
study, the authors needed immersed 10 female and 11 male
lightly-clothed, nonexercising subjects in water at 0 deg C until
their core temperatures reached  35 deg C.  The times required for
this were in the range 25-40 min.

The source for the journal article was a search on Medline -
http://www.ncbi.nlm.nih.gov/ -  using the terms water hypothermia rate
core temperature and limiting the search to studies in humans and
presented with abstracts.  The reference was no. 37 in the list. 
However, if you  just search on the surnames of the authors together
with a couple of words from the title, you should retrieve the record
immediately.

An excellent treatment of a complicated question, thoroughly documented.

I can't find the information you are seeking.  I did find a web site
which gives survival times at different water temperatures, as well as
the expected times to exhaustion and unconsciousness at
http://www.seagrant.umn.edu/tourism/hypothermia.html

Dr. Hayward's research is not without controversy for his use of what
many consider to be forbidden knowledge. Dilemmas arise even while
trying to *save* lives.

From death comes life.

huntsman

-----

Jewish Law Articles
http://www.jlaw.com/Articles/NaziMedEx.html

The Ethics Of Using Medical Data From Nazi Experiments
Baruch C. Cohen

[Excerpt]

HAYWARD'S EQUALLY CHILLING DILEMMA

Doctor John Hayward is a Biology Professor at the Victoria University
in Vancouver, Canada. Much of his hypothermia research involves the
testing of cold water survival suits that are worn while on fishing
boats in Canada's frigid ocean waters. Hayward used Rascher's recorded
cooling curve of the human body [*] to infer how long the suits would
protect people at near fatal temperatures. This information can be
used by search-and-rescue teams to determine the likelihood that a
capsized boater is still alive.

According to Kristine Moe's survey in the Hasting Center Report,
Hayward justified using the Nazi hypothermia data in the following
way:

"I don't want to have to use the Nazi data, but there is no other and
will be no other in an ethical world. I've rationalized it a bit. But
not to use it would be equally bad. I'm trying to make something
constructive out of it. I use it with my guard up, but it's useful."

Hayward continued to rely on the data even though the subjects were
lean, malnourished, and emaciated prisoners, with little or close to
no insulating body fat (and therefore unrepresentative of the general
populace to be benefitted from the study). Hayward still trusted the
data because the general linear shape of Doctor Rascher's cooling
curve (as the prisoners neared death) appeared to be consistent with
the cooling curve at warm temperatures.

Since a better knowledge of survival in cold water has direct and
immediate practical benefits for education in cold water safety, and
in the planning of naval rescue missions at sea, Pozos and Hayward see
it criminal not to use the available data, no matter how tainted it
may be.

----- 

*See "Freezing Experiments" on the Web page cited above.

Not having seen the full paper by Hayward, I cannot say whether the
study cited here is or is not based on Nazi data, and whether he did
or did not clarify and/or condemn the source of his data.  An article
appeared in Omni in 1982 which contains the following: "At the
University of Victoria, in British Columbia, Dr. John Hayward has been
dunking people in ice water and marching them through artificial
rainstorms so that he can study the effects of hypothermia. More than
500 volunteers have agreed to journey one-third of the way to death --
just 6ºF from what could be a fatal chill -- in the service of
science.  "The standard wisdom was that you could survive only three
or four minutes in ice water," Hayward says. "I didn't believe it, and
I set out to find the truth." " (The Iceman Reviveth by Timothy
Perrin,
http://www.writingschool.com/timperrin/articles/iceman.htm).  

I also found that Hayward was awarded the British Columbia Science and
Engineering Award in Industrial Innovation in 1981 for inventing a
thermal jacket designed to increase survival in cold water
(http://www.scbc.org/e-synapse/pdf/sy9811p.pdf )

The dilemma of unethical research neither started nor ended in the
concentration camps.  It has touched prisoners, soldiers, mentally
handicapped children, workers, etc etc.  The problem stems from the
fact that much of Western biomedical science has historically been
based on the premise that scientific study requires experimentation in
living subjects and that the closer these are to humans in behaviour
and physiology the better.  The question of rights has always been
central, although usually hidden: there has been the implication that
some rights can be lost because the subject is: an animal, a convicted
criminal, a member of the army, an employee, an undeveloped fetus, a
member of a specific race, handicapped, and so on.  The position of
the dividing line between having and not having rights has been
different among different individuals and different societies.

To my mind the dilemma can only be fully solved once and for all, so
that no atrocities can occur again, if scientists place humanity at
the top of their scientific agendas.  This means developing ways to do
good science which do not require the sacrifice of living higher
organisms.  "The greatest scientific achievements have always been the
most humane and the most aesthetically attractive, conveying that
sense of beauty and elegance which is the essence of science at its
most successful".  (William Russell and Rex Burch, The Principles of
Humane Experimental Technique, 1959 
http://altweb.jhsph.edu/publications/humane_exp/het-toc.htm )

Great work, tehuti!