How long can humans survive w/o food or water?

From:http://ask.metafilter.com/41162/How-long-can-humans-last-without-water

The survival rule of thumb is: 3 hours without shelter, 3 days without water, 3 weeks without food.

This article suggests that an adult in comfortable surroundings can survive for a week with no or little water intake.
posted by pharm at 5:43 AM on June 29


The crew of the Lady Be Good made it for eight days.

Hi
3 days without water but about 40 days without food. This will depend on the person being male/female, big build or small, what activity they do the more manuel then quicker they will need to begin eating.

The first 3 -4 day without food will cleanse your system. You blood goes through D-tox getting rid of all the rubbish in our body. This period is usually accompanied by headaches and hunger pangs like you have never known, as your body goes through D-Tox.

After 3 -4 days the headaches will stop and your mind is much clearer. You have power to do things but the longer you don't eat the less power you have to do or you will hurt your body.

This time your body ajusts, it is not getting any food so it will begin to use up the body fat. This doesn't hurt and you don't feel hungry. At about 40 days (varies depending) starvation will begin to set in. You will start to feel hungry again. At this point you NEED to start to eat or it could damage your body or even kill it if no action is taken.

A point you need to consider:
When you don't eat you don't need to sleep as much. How many times after a big meal you feel sleepy eh? When you don't eat your body isn't working as hard to digest the food etc SO your need for sleep decreases. When a person hasn't had food for 20 -40 days you will only sleep just a few hours a day. That is all your body needs.

However saying that your story is a fantasy story so you can get round these points coz you use a spell.
1) They could survive much longer coz they are "under the spell".
2) They could sleep, again coz they are under the spell.
If you want this bit to be realistic then the people WON'T sleep if they don't eat.

Your call.
Kev

Ziljon said:

From:http://ask.metafilter.com/41162/How-long-can-humans-last-without-water

The survival rule of thumb is: 3 hours without shelter, 3 days without water, 3 weeks without food.

This article suggests that an adult in comfortable surroundings can survive for a week with no or little water intake.
posted by pharm at 5:43 AM on June 29


The crew of the Lady Be Good made it for eight days.

Click to expand...

Three hours without shelter? I'd better run outside and tell the mailman he's about to pop his clogs!

I learned it as: three minutes without air, three days without water, three weeks without food.

KCpotatohead said:

When you don't eat you don't need to sleep as much. How many times after a big meal you feel sleepy eh? When you don't eat your body isn't working as hard to digest the food etc SO your need for sleep decreases. When a person hasn't had food for 20 -40 days you will only sleep just a few hours a day. That is all your body needs.

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I'm not sure where you're getting your information, but I know this is not true, or at least not completely true. The body goes through a daily rhythm of sleepiness and activity that has nothing to do with food intake. One of those sleepy periods comes in mid-afternoon, which is often blamed on a large lunch but has nothing to do with it. Also, many many many studies have shown that almost everyone needs 7-8 hours of sleep in every 24 (more for teens, much more for children, and considerably more for babies). Sleeping allows the body to repair itself, among other things, and those who go without enough sleep start to lose some higher order thinking functions--starting with a sense of humor and organization skills, and if the sleep deficit is drastic enough (and if the person is not getting enough REM sleep, when we dream), can lead to hallucinations and even death.

I'd add some links to back myself up, but I'm running late this morning and haven't had breakfast yet.

Mo Hayder wrote a book in which the killer starved/dehydrated people to death. Think it was called The Treatment.

I'm told 4 days max without water before death (barring extreme factors that might contribute to rapid dehydration such as a hot desert enivronment).

8 weeks max without food befiore death (if you have average to above-average body fat).


And if it's a fanatsy--who cares? They'll be fine in a fantasy! Make up SOMETHING so that they will be totally fine for however long or longer.

Saanen,

I am not just talking off my head or from dreamland. This info is from research and personal experience. I often fast. I have fasted for 27 days once. You body does change and IT DOES NOT NEED AS MUCH SLEEP.
You talk of the daily rhythm. When you don't eat then you are changing all of this so the body ajusts.

I will get the info to back this up, but trust me YOUR BODY DOES NOT NEED AS MUCH SLEEP IF THERE IS NOT FOOD EATEN.

Kev.

The environment will seriously affect how long you can go without water.

I'm from Arizona and do a fair amount of hiking in the desert. I *don't* hike during the heat of the day in summer; even in winter or morning/evening, however, people can die in less than a day from dehydration and electrolyte imbalances. I've rescued a few even in *good* weather who thought they could go on a three or four hour hike without water because it was only a "few hours."

Even seen a few people in pretty bad shape after sitting in a boat for several hours on a hot day with no drinking water. A few hundred people a year die here of heat and hydration related issues ...

Rehydrating someone who's severely dehydrated with plain water can kill them too, FYI.

KCpotatohead said:

Saanen,

I am not just talking off my head or from dreamland. This info is from research and personal experience. I often fast. I have fasted for 27 days once. You body does change and IT DOES NOT NEED AS MUCH SLEEP.
You talk of the daily rhythm. When you don't eat then you are changing all of this so the body ajusts.

I will get the info to back this up, but trust me YOUR BODY DOES NOT NEED AS MUCH SLEEP IF THERE IS NOT FOOD EATEN.

Kev.

Click to expand...

I've gone 3 days without water, and more than a week at a time without food. No side effects with the first; but I did sleep a lot less when I went without food. I was also experiencing clinical depression at the time, so that may have been what was disrupting the sleep cycle.

Once I slept on my couch for three days without moving, waking up, eating, drinking, or using the bathroom.

I was also pretty sick. My couch was in the livingroom of an air-conditioned home.

Pat~ said:

I've gone 3 days without water, and more than a week at a time without food. No side effects with the first; but I did sleep a lot less when I went without food. I was also experiencing clinical depression at the time, so that may have been what was disrupting the sleep cycle.

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I went without a wink of sleep for one week and no food for the same amount of time but had a nervous breakdown and ended up in hospital.

Okay--I read this far:

Duped said:

I went without a wink of sleep for one week

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and I thought, "Oh my GOD! A person can suffer a complete psychotic breakdown if they go that long without sleep!"

But then I read the next part:

Duped said:

and no food for the same amount of time but had a nervous breakdown and ended up in hospital.

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and thought, "Yep."

(And I hope you're doing better.)

Concerning what Saanen and KCpotatohead are discussing:

I also have fasted for religious purposes. I have read many books on fasting. I did a research paper in college about fasting. I agree with everything KCP had to say EXCEPT for the needing less sleep thing. And even then, I don't actually dissagree with his claim of needing less sleep, I am only willing to say that I never came across it in any of my research. However, such a claim makes sense to me because it has been medically demonstrated (for more than 50 years now) that the human body expends anywhere from 20% to 40% of its daily energy just in the effort of digesting and processing food. By eliminating food intake, you're saving massive amounts of internal energy stores. But still--I have never read it, so a link from KCP would be a good thing at this time. I'm not being picky per se, just extremely cautious because fasting can be a dangerous thing for some people, so I think it's prudent to get the facts straight for the sake of anyone here who ight read all of this and assume they can fast and be okay.

I never went on a fast that lasted longer than 4 days. But I do know people who have fasted for as long as two to three weeks. They all report the first three days is killer because of the toxin release KCP mentioned. Caffiene withdrawal and headaches and obsessive hunger pangs are common. But after that third day, it's supposedly smooth sailing. Sadly, it was never that easy for me. So I always stopped at 4 days. Some people have extenuating medical situations that won't permit them to fast at all. So a doctor should be consulted before beginning any kind of a fast.

The first time I ever embarked upon a religious fasted I was 20 years old and I mistakenly assumed that fasting also meant no water. After just two days I was a mess, my lips were so parched they were cracking and bleeding. A friend asked me what was up, and I told her about my fast. While she was supportive of my decision to fast, she kindly informed me that I was endangering myself by going without the water. I never made that mistake again. That was when I started reading books on how to fast.

Okay, since they're asleep and not expending energy running around, they'll last longer. Remember Terry Schiavo? She died 13 days after her feeding tube was removed. Though I suspect there might have been organ damage before she actually died.

The rule of thumb is:

Three minutes without oxygen.

Three hours without shelter.

Three days without water.

Three weeks without food.

James D. Macdonald said:

The rule of thumb is:

Three minutes without oxygen.

Three hours without shelter.

Three days without water.

Three weeks without food.

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The rule of thumb 'three hours without shelter' seems pretty odd.

Sure, I can believe 'Three hours without shelter (if you are stark naked in freezing conditions)', but that's a hell of a disclaimer !

Mac

I suspect that how long without is variable. Put a dozen people into a coma in a cavern for a week and not all of them are going to live. It is amazing at how little it takes to kill some people or what others can survive. Throw in an endless variety of circumstances and it becomes even less predictable. The rule of thumbs are nonsense. They say three minutes without air but it would be murder to pull someone out of the water and say he was under for five minutes I don't have to try and recessitate or give up searching for someone in a winter storm after three hours. The rule of thumb really means that some people can die in as little as three minutes.

Many Christians try to emmulate the fast that Jesus did in the Bible: 40 days (5 1/2 weeks). I know many people who have done it and succeeded with no ill-effects (but you still gotta drink water!)

6-8 weeks has been cited by the medical community as death point. Thinner people (those who started out thinner) will die at the 6-week point while heavier people will die at the 8 week mark.

And


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SPOILER ALERT FOR THE MOVIE 28 Days Later

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That film also went by the 8-week rule. The last of the "infected" all died off of starvation after 8 weeks (two successive instances of 28 days). That was how the film ended, with the last of the infected dying and we could see that they had all been reduced to skeletal specimens of starvation. And the producers even blatantly demonstrated the timeline for us by putting up a super onto the screen at the end that read "28 days later" and then they showed us the dying infected people.


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END SPOILER

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Leva said:

The environment will seriously affect how long you can go without water.

I'm from Arizona and do a fair amount of hiking in the desert. I *don't* hike during the heat of the day in summer; even in winter or morning/evening, however, people can die in less than a day from dehydration and electrolyte imbalances. I've rescued a few even in *good* weather who thought they could go on a three or four hour hike without water because it was only a "few hours."

Even seen a few people in pretty bad shape after sitting in a boat for several hours on a hot day with no drinking water. A few hundred people a year die here of heat and hydration related issues ...

Rehydrating someone who's severely dehydrated with plain water can kill them too, FYI.

Click to expand...

How does that last part about plain water figure? Is it a nutrient thing?

If you give a dehydrated person too much water their body can't cope with it. You are suppose to only give a little bit at a time.

As for the sleep i am still looking.
K

Here's what Wiki says about sleep, although Wiki is certainly not wholly reliable all of the time:

"1. Thai Ngoc, born 1942, has been awake for 33 years or 11,700 nights, according to Vietnamese news organization Thanh Nien. [6] At the time of the report, Ngoc suffered from no apparent ill effect (other than the fact that he cannot sleep). He was mentally sound and was able to carry 100kg of pig feed down a 4km road. It was said that Ngoc acquired the ability to go without sleep after a bout of fever in 1973. In April, 2007, however, Ngoc reported that he was beginning to feel ill due to the lack of sleep.[7]


2. Randy Gardner holds the Guiness World Record for intentionally having gone the longest without sleep. In 1965, Gardner, then 18, stayed awake for 264 hours (about 11 days) for a high school science project. [8] He experienced significant deficits in concentration, motivation, perception and other higher mental processes during his sleep deprivation. However, he recovered normal cognitive functions after a few nights' sleep.

On May 25th, 2007 the BBC reported that Tony Wright beat the Guinness World Record by staying awake for 11 days and nights. [9] The Guinness Book of Records has, however, withdrawn its backing of a sleep deprivation class because of the associated health risks.


3. People born with the rare genetic disorder Morvan’s fibrillary chorea or Morvan's syndrome can go without sleep for several months at a time. Michel Jouvet and his colleagues in Lyon, France, studied a 27-year-old man and found he had virtually no sleep over a period of several months. During that time he did not feel sleepy or tired and did not show any disorders of mood, memory, or anxiety. Nevertheless, nearly every night between 9:00 and 11:00 p.m., he experienced a 20 to 60-minute period of auditory, visual, olfactory, and somesthetic (sense of touch) hallucinations, as well as pain and vasoconstriction in his fingers and toes.[8] In recent investigations, Morvan's syndrome has been attributed to serum antibodies directed against specific potassium (K+) channels in cell and nerve membranes."