• Question: how long do humans survive without water and food?

    Asked by to Aimee, Chris, Dave, Greig, Laurence on 16 Jun 2014. This question was also asked by .
    • Photo: Dave Jones

      Dave Jones answered on 16 Jun 2014:

      People can survive a long time without food. Gandhi famously fasted for 21 days, and some people who have been lost in the wilderness have gone much longer. A little research seems to show that about 8 week would seem like a maximum for a normal, healthy adult, but you definitely wouldn’t be normal or healthy afterwards!
      Water is very different. People need much more water to be able to survive. For example, in the heat of the desert someone could start suffering from dehydration in just a few hours. In a place with a reasonable temperature and one that wasn’t too humid or too dry, someone could go a few days without water, maybe 4 or 5, but certainly no longer!

    • Photo: Greig Cowan

      Greig Cowan answered on 16 Jun 2014:

      It depends where you are. Death Valley is a large desert valley in California where the average summer-time high temperature is about 46 degree Celsius! After a only a couple of hours in that you will become dehydrated and disorientated and likely pass out. Regularly people are reported missing there after having just gone out for a short walk…

      You can last without food for much longer, although it isn’t much fun!

    • Photo: Aimee Hopper

      Aimee Hopper answered on 16 Jun 2014:

      A normal person needs about 2.5 litres of water a day to function properly.
      The brain is made up of 85% water, and the human body is around 70% of the liquid. You can see that water is essential to the survival of a person!

      Without water, the brain shuts down, and so the body cannot function. 3 days without it and you’ll be in REALLY deep trouble. There are stories of people reaching just over a week, but very few people would last that long!

    • Photo: Laurence Perreault Levasseur

      Laurence Perreault Levasseur answered on 21 Jun 2014:

      I’ve read it’s possible for the human body to survive without food for a maximum of 2 months, so that would agree with what Dave said. But this is conditional to a lot of things. For example, the temperature should be warm and nice, so that the body doesn’t need to spend lots of energy to keep itself warm. Also, exercising or even moving around would decrease this number, because it burn extra energy.

      Water is a completely different story. A healthy person in good shape would probably make it for about 3-5 days without water, if the conditions (like the temperature and humidity) were ideal.

      But there has been some amazing exceptions. In 2006, a man in Japan went missing on a trail, and he survived without food or water for 24 days!! When he was found, his body temperature was only 22C (it’s usually 37C!!!), so doctors think he might have survived because he went into an ‘hibernation-like’ state (I would REALLY not recommend to try this, though!!)

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