More than 663 million people around the world do not have regular access to clean drinking water. For them, the threat of dehydration is ever-present and its consequences are easily recalled.
Dehydration, however, is far more common around the world than you might think and you don't have to run a marathon to experience it.
It occurs in stages, gradually spreading through the body and clouding a person's ability to function. Even for people who have regular access to clean water, mild dehydration occurs all the time. In fact, up to 75 percent of US citizens suffer from chronic dehydration.
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In the simplest description, dehydration happens when water moving out of cells in the human body exceeds water being taken in. Water, which accounts for around 60 percent of the human body, performs and assists vital functions: regulating body temperature; enabling blood flow; metabolizing food; insulating organs, muscles, the skeleton, and brain; lubricating joints; flushing toxins from the body; and more.
The most common causes of dehydration are fever, excessive heat, exercise, diarrhea, vomiting, disease, and lack of access to clean water, all of which can multiply one another.
Water is lost when we breathe, sweat, urinate, and defecate. It's constantly leaving our bodies and constantly needs to be replenished. Since the body is so dependent on water, though, it's also really good at signalling when more water is needed. The trick is learning how to recognize these signals and being more self-aware of your body in general.
Dehydration begins to be appear when just one percent of the body's water is lost. At this point, you begin to feel both mentally and physically tired, as your body struggles to power itself and carry out basic functions.
In your brain, water helps to create energy, neurons, and hormones; facilitates the transmission of neurons; removes toxins; delivers nutrients; relieves pressure; and generally enables proper functioning. Even the slightest decrease of water causes "brain fog," and you begin to lose the ability to focus and form memories and your mood worsens.
So if you start to feel lethargic and get a headache during the day, you might be slightly dehydrated.
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Elsewhere in the body, your heart begins to beat faster, your muscles stiffen, and the rest of your organs struggle. This is when your body triggers its hallmark signal—thirst. Your kidneys are also signaled a message to retain water, causing the body's urine to turn dark.
Drinking water at this point can alleviate these symptoms. Certain beverages, such as milk, are even more hyrdrating because they contain nutrients that slow down the release of liquid. Eating a balanced diet full of minerals, fatty acids, and electrolytes is also essential for staying hydrated.
As dehydration climbs to five percent water loss mark, more severe symptoms are felt such as cramping, irritability, rapid breathing, fever, and others can occur in the body. And at 10 to 15 percent water loss, vision dims, urination becomes painful, muscles shrivel and spasm, and delirium can set in. Anything beyond 20 percent fluid loss is usually fatal as organs begin to fail.
All throughout, the body fiercely clings to remaining water supplies. But since the very act of being alive involves using up water, this becomes eventually impossible.
For people with acesss to clean water, dehydration rarely progresses beyond the most mild level—which is still unpleasant.
For people without access to clean water, dehydration can often get to dangerous levels. Millions of children die each year because of water-borne illness, which is exacerbated by a lack of clean water. Diarrhea, for example, is the second leading killer of children under the age of five, and is partly fatal because of the body's rapid loss of water.
All kinds of dehydration should and can be avoided. But the milder forms can usually be solved by the person suffering from it, whereas the more severe forms are often the result of instituional problems.
And it's the more severe kind of dehydration that the world has to come together to solve.