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Author Topic: Dehydration and starvation  (Read 8340 times)

Offline artistic

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Dehydration and starvation
« on: 12/08/2006 18:07:22 »
I watched I Shouldn't Be Alive a couple of months ago on Discovery Channel and realized that they could actually survive without food for around 10 days! Is there something I do not know?


 

another_someone

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Re: Dehydration and starvation
« Reply #1 on: 12/08/2006 19:08:39 »
Starvation you can survive for quite a while - the limit for dehydration is much shorter.



George
 

Offline neilep

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Re: Dehydration and starvation
« Reply #2 on: 12/08/2006 19:26:16 »
Yep...george is right .....going without food is far less hostile (in the initial stages) than going without water.

In fact...I am sure ten days is a conservative figure when it comes to food ( for the average person !!)

Men are the same as women, just inside out !
 

Offline realmswalker

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Re: Dehydration and starvation
« Reply #3 on: 13/08/2006 08:47:01 »
ive seen something like 2 months is the top limit for no food
a week with no water
5 days with no sleep
10 minutes with no air
 

another_someone

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Re: Dehydration and starvation
« Reply #4 on: 13/08/2006 11:14:38 »
quote:
Originally posted by realmswalker

ive seen something like 2 months is the top limit for no food
a week with no water
5 days with no sleep
10 minutes with no air



These sound very plausible as the limits for survival, but I suspect that if you even get close to these limits, you could cause yourself permanent damage to various organs, teeth, and maybe the brain.



George
 

Offline iko

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Re: Dehydration and starvation
« Reply #5 on: 13/08/2006 11:40:12 »
Here comes the cofactor maniac again!
Seriously.

Malnourished humans, anorectics, hunger-strikers, starving people (even who has been vomiting for two weeks in pregnancy or chemo), alchoholics, patients on unsupplemented parenteral nutrition, die frequently because of thiamine (vitamin B1) deficiency: beriberi, Wernicke encephalopathy, Korsakoff disease. "Shoshin beriberi" is the hyperacute presentation (heart failure), and is fatal in a matter of hours.
You may cross thiamine with any of the previous terms for details on the PubMed database:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed

The reason is simple: our body can stock just a little amount of thiamine and after 2-3 weeks it is all gone.
Vitamin B1 is a cofactor of several key-role enzymes in the energy chain production of the cells...so even if you have fuel (glycogen in the liver, proteins, fat) you cannot use it.
When the batteries are gone the weaker system (heart, brain, nerves) will be damaged first, depending on the different characteristics of each of us.
Heart damage (even after cardiac arrest) may resolve completely in weeks, brain and nerve damage (as with B12 deficiency) may reverse only in part and leave permanent sequelae.
This is the reason why you never give glucose to a starved child without thiamine first: 50-100mg parenteral, because intestinal adsorption is restricted at 5mg/day.
Glucose alone would poison her/him (refeeding syndrome) producing toxic amounts of lactate and pyruvate unusable by the blocked biochemical factory.
Neat eh?
iko
 
« Last Edit: 07/09/2006 22:52:53 by iko »
 

Offline iko

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Re: Dehydration and starvation
« Reply #6 on: 13/08/2006 15:44:19 »
quote:
These sound very plausible as the limits for survival, but I suspect that if you even get close to these limits, you could cause yourself permanent damage to various organs, teeth, and maybe the brain.



Citing teeth problems you remind me of scurvy, vitamin C deficiency, that goes together with starvation but would be more evident after a beriberi condition (we die of beriberi first).  Typical scurvy is with normal thiamine but no ascorbic acid (no fruit, no veggies for over one month).
But this is another story.
iko
 

Offline Mjhavok

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Re: Dehydration and starvation
« Reply #7 on: 13/08/2006 18:24:10 »


As for 10 minutes without air. Wow. I thought after 4-6 minutes brain damage insues.
Steven

The people who practise Free diving http://en.wikipedia.org/wiki/Free_diving have to hold their breaths for a well long time  !

« Last Edit: 18/08/2006 13:32:11 by neilep »
 

another_someone

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Re: Dehydration and starvation
« Reply #8 on: 13/08/2006 18:46:31 »
quote:
Originally posted by Mjhavok
As for 10 minutes without air. Wow. I thought after 4-6 minutes brain damage insues.



The limitation is the length of time the brain is starved of oxygen (I thought around 2 minutes before the brain starts to become irrevocably damaged although this can be extended if the temperature is carefully reduced).

As a teenager, I used to regularly be able to hold my breath underwater for up to around 5 minutes (after hyperventilating only about 2 minutes without hyperventilating) I'll leave it to other people to asses whether I suffered permanent brain damage from that.

The bigger problem with holding your breath is the build-up of CO2 in the blood, rather than oxygen starvation which is why hyperventilation can extend the length of time you can hold your breath.



George
 

Offline iko

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Re: Dehydration and starvation
« Reply #9 on: 13/08/2006 18:48:13 »
quote:
As for 10 minutes without air. Wow. I thought after 4-6 minutes brain damage insues.



I wouldn't give it a try.
We should talk of average values, and in case of humans...the range should be quite wide.  People pass out quite easily these days (!!!)
If somebody is still alive after prolonged hypoxia, she/he should be resuscitated anyway to survive.
iko
« Last Edit: 16/08/2006 21:50:22 by iko »
 

Offline gecko

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Re: Dehydration and starvation
« Reply #10 on: 18/08/2006 07:52:32 »
why is sleep so important for survival?

i thought the records for sleep deprivation were much longer, but theres obviosuly something i dont know.

what can kill you about not getting any sleep?
 

Offline weed4me

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Re: Dehydration and starvation
« Reply #11 on: 29/08/2006 23:56:51 »
Hallucinations, paranoia, disorientation, thats basically what happens from lack of sleep, so in a nutshell, sleep deprevation is a form of pshycosis. also a favoured torture used by the KGB durin WW2.

"By the week's end, people lose their orientation in place and time - the people you're speaking to become people from your past; a window might become a view of the sea seen in your younger days. To deprive someone of sleep is to tamper with their equilibrium and their sanity."
http://news.bbc.co.uk/1/hi/magazine/3376951.stm [nofollow]

You probably couldnt DIE from sleep deprevation, the longest held record i believe is 11days, but im pretty sure it would seriously mess with your sanity. that help??

"You have to stay in shape. My grandmother, she started walking five miles a day when she was 60. She's 97 today and we don't know where the hell she is."
 

Offline Mjhavok

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Re: Dehydration and starvation
« Reply #12 on: 30/08/2006 02:51:16 »
In humans, extended sleep deprivation causes microsleep sessions to develop. You fall a sleep for seconds at a time and don't even know you have been asleep.
 

Online syhprum

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Re: Dehydration and starvation
« Reply #13 on: 05/09/2006 20:24:20 »
When torture was officially banned for interrogation in the seventieth century (except with special dispensation from parliament) sleep deprivation was still allowed, four or five days was normally sufficient

syhprum
 

Offline Mjhavok

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Re: Dehydration and starvation
« Reply #14 on: 08/09/2006 06:30:58 »
Interesting.
 

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Re: Dehydration and starvation
« Reply #14 on: 08/09/2006 06:30:58 »

 

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