View Full Version : How long can you survive without water?

10-20-2011, 07:17 PM
Three infants after the Mexico City 1985 earthquake and one after Haiti 2010 earthquake survived in the ruins for seven days, obviously without food and water.

Has anyone heard for stories like that? More than seven days without water? I'm just collecting some facts.

10-20-2011, 07:21 PM
I was always taught the rule of 3. Three minutes without air, three days without water, and three weeks without food. Now there are always acceptions to each rule, and I would say you could survive for just about a week and a half with absolutely no water, but take into account that you were in awesome physical health in the prime of your life. Anyone older or younger or with health condistions will have less time.

10-20-2011, 07:26 PM
It's a lot of theoretical considerations behind this - the longest I've heard was 10 days without water at moderate ambient temperature, but this was only some calculation.

I'm strictly interested in published reports.

I personally knew few people that went 45 days without food while continuing with their daily work, though.

10-20-2011, 08:01 PM
You lose 2L a day just breathing and more than that in urine, sweat and other losses. To maintain equilibrium you need to replace that amount daily. More if it is a hot day or you are working particularly hard (and therefore breathing and sweating more).

You do, however, also create water in the form of metabolic waste from respiration and some of that is what is lost in the lungs when you breath out.

I suspect the cases you mention may have been assisted by something else. Perhaps they had access to some small amounts of water from rain or similar? I think the 3 days thing is no water at all - not even small amounts.

10-20-2011, 08:08 PM
Many of the longer term Haiti survivors had access to some liquid. I remember one that subsisted on a can of soda for several days.

10-20-2011, 08:12 PM
It depends on the level of dehydration also. IIRC around 20% is the point where death with occur.

10-20-2011, 08:12 PM
I assume the infants from my first post did not have any assistance and seven days is not an unbelievably long period. I'm not taking that as a 100% proof, but as a report, as it was, though.

10-20-2011, 08:19 PM
Infants are weird in what they can survive if the are still in the fixed action pattern mode.

Most people will be lucky to go four days.

10-20-2011, 08:30 PM
Yes, I'm searching for the extreme rather than average or safe periods.

10-20-2011, 08:37 PM
Hard to say. If they are healthy, conserving energy, and in a confined but humid space I bet a few weeks would not be impossible.

10-20-2011, 10:24 PM
I know there was a medical reason those babies in Mexico survived. I recall watching the rescuers pull them out of the rubble (from out of their incubators buried in the rubble) and I was crying. (And I am not the emotional sort.) The fact they were alive - everyone was calling it a miracle.

But it indeed was science and had something to do with their metabolism and fat reserves - though I do not recall the exact biological mechanism involved.

10-21-2011, 12:05 AM
Here is a y 2003 article from the Seattle Times (http://community.seattletimes.nwsource.com/archive/?date=20030921&slug=miracle21), where it is said one baby was 4 days old when the 1985 Mexico City eartquake occured and was found alive 235 hours later (and still alive in 2003).

A woman survived eight days (http://www.msnbc.msn.com/id/21020571/ns/us_news-life/t/woman-missing-days-found-alive-ravine/#.TqCIBtLiGU8) without food and water after being trapped in a car after an accident.

10-21-2011, 09:59 AM
Well, there's this awesome Indian holy man who as of right now has gone for 6 days without food or water, verified by Indian military scientists holding him in isolation/observation in a hospital.


It will be interesting to see what comes of it. I have a very hard time believing 70 years, but then again most adult humans would be dead after 6 days, so who knows?

Edit: Okay, I guess this is from 2010 (read the wrong date above the article). Still interesting though. 6 days is longer than I would have guessed someone could survive.

10-21-2011, 12:13 PM
The site:gov search on Google does not give one single result for the abovementioned man. I have found no results of the so called investigation published in any kind of online scientific publication.

10-21-2011, 01:04 PM
Try PubMed and see what is there... I saw the news articles about this guy last year but no indication that they'd published anything other than press releases...

10-21-2011, 01:08 PM
Pubmed is limited to trials and studies, more or less. So I need to go through the news. Now I search this way: seven...eight....

10-21-2011, 01:33 PM
As people have said, the Rule of Threes is generally a decent guideline - namely, that the average adult in reasonable health will last for:
- 3 minutes without air, at rest or low activity
- 3 hours in harsh weather (desert, arctic, etc)
- 3 days without water in "normal" conditions
- 3 weeks without food, at average activity levels

There are other factors, obviously, but that's the general idea. Injury will decrease all of these, as will strenuous activity. Injury will also lower the threshold for what counts as strenuous, as will being in the latter stages of dehydration, starvation, or exposure. The 3 minutes without air also shows a huge amount of variance (usually towards shorter times) because people tend to panic when they can't breathe, which uses up their oxygen faster. Also, in real-life conditions, it tends to be the case that the air is replaced, rather than removed, so what happens is that your brain freaks out and you find yourself taking a deep breath of smoke or water or whatever you're in.

The thing to bear in mind is that these are all averages. I've heard of cases where people have lasted nearly twice as long as these rules say they should, but likewise there have been cases where people expired some time beforehand, much to the sadness of the rescue crews who were using the Rule of Threes to guide them. The rules can be beaten if you prepare well, and/or have a high level of general fitness, and/or rest a lot, and/or are very lucky. People surviving in rubble after disasters is not unheard of, partly because they're usually unable to move around and often unconscious for some appreciable portion of the time they're there, which means they use much less energy (which is why we've evolved to pass out when seriously injured).

10-21-2011, 02:21 PM
Pubmed is limited to trials and studies, more or less. So I need to go through the news. Now I search this way: seven...eight....

PubMed will also have case studies which this would come under. If they actually published anything in a reputable, peer reviewed journal on this guy the papers will be available on pubmed. If however all they did was tell the media then it won't be there and, frankly, I'd not take it seriously. In any 'science' news story, I always try to look for the original journal that 'proves' it because there is often a lot of hyperbole and interpretation between what the researchers wrote and what the journalist thought they wrote.

10-21-2011, 02:31 PM
I haven't found anything relevant on PubMed. They are firemen and others who actually dig people out of the ruins that may give most reliable information about the timing and circumstances.

10-21-2011, 06:10 PM
Pubmed has case studies, and unlike the media tends to be accurate. Failing that I would suggest using a basic reference like The Biology of Human Survival by Piantadosi.

10-21-2011, 06:19 PM
The problem is no one normal can do a case study about how long someone can survive without water. There isn't and should not be anything like that on Pubmed. Or someone let me know, but I did my search.