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  • Every living organism we know of requires water to survive - it's part of the reason

  • we look so feverishly for water on other planets across the universe, and consume it consistently

  • every day here on Earth. So what would happen to your body if you stopped drinking water?

  • Of course, when we say 'water' we're including all fluids which simply contain water - like

  • juices, pop, or tea. Much like the desire to breath in oxygen, thirst is a survival

  • instinct. H20 is the most abundant molecule in the human body making up, on average, 65%

  • of an adult. As a universal solvent, it carries nutrients and hormones through the body, regulates

  • body temperature, cushions our joints and even lubricates our eyes. You produce around

  • 1.5 litres of urine every day, with another litre lost from breathing, sweating and...pooping.

  • So it's essential that the body replaces this liquid.

  • The thirst centre of the brain is located in the hypothalamus, and is constantly using

  • sensors in your blood vessels to monitor the amount of sodium and other substances in your

  • body. For example, if you sweat too much, your blood volume and pressure fall. The brain

  • then detects this change and creates the urge to drink something, NOW! So what happens if

  • you are unable to satisfy this thirst?

  • The initial signs of dehydration are the obvious dry mouth, following which your urine becomes

  • darker with a stronger odor, as your body attempts to conserve more fluids. The lack

  • of H20 then begins to affect your brain - you may feel light headed, have a slower response

  • time and decreased ability to feel pain. In fact, when you're dehydrated, your brain tissue

  • literally shrinks. In studies observing hydrated vs. dehydrated participants, the same task

  • required more brain power and oxygen in dehydrated individuals compared to those fully hydrated.

  • After a day or two with no fluids you'll stop peeing all together, have trouble swallowing,

  • suffer from muscle spasms and likely experience nausea - after all, your body can survive

  • without food much longer, and attention to digestion is not a priority at this point.

  • Eventually, victims may become delirious with severely impaired brain function. Interestingly,

  • studies looking at elderly patients who suffer from delirium, found that many are simply

  • suffering from chronic dehydration in the first place. After even more time without

  • water, the blood stops flowing to your skin, reducing heat loss but increasing your core

  • body temperature. This can lead to a grey-blueish tinge to your skin. Beyond 3-5 days without

  • water, and your body will begin to shut down it's organs, and eventually the brain.

  • Of course, unlike the plentiful oxygen we breath, only 2.5% of all Earth's water is

  • fresh; most of which is locked up in glaciers, ice caps and underground lakes known as aquifers,

  • leaving less than 1% available for drinking. And most of this water is actually used to

  • grow crops; approximately 500 billion litres of freshwater is used daily for agriculture

  • in the USA alone, with another 500 billion litres to cool electric power plants. And

  • as our personal drinking sources become increasingly contaminated, over 783 million people on earth

  • are unable to access clean water.

  • Scientists around the world are trying to find solutions to this problem - from attempts

  • to remove salt from ocean water, tap into underground aquifers and creating innovative

  • water filtration systems. If we look to space, NASA has developed technology for astronauts

  • to turn their urine into water more pure than what we drink on earth. But we can't just

  • rely on science and technology - perhaps the solution relies on us as a species to understand

  • and contribute to this global water crisis.

  • If you want to help in the mission to end global thirst, join in World Water Day on

  • March 22nd. There are a lot of really amazing projects out there, like or even

  • the awesome UNICEF app which donates 1 day of clean water to child in need, for every

  • 10 minutes you put your phone down. We'll leave links in the description for these and

  • other great water charities. Small investments really do make a huge difference.

  • We'll be donating all the proceeds from this video to a water project close to us called

  • Morocco 5 Villages - so thanks for supporting and watching. And subscribe for more weekly

  • science videos!

Every living organism we know of requires water to survive - it's part of the reason

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B2 US water body thirst brain dehydrated urine

What If You Stopped Drinking Water?

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    Ashley Chen posted on 2014/07/28
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