These Are the Effects of Dehydration on Your Body, According to a Doctor

Not consuming enough water is a serious problem.

Black Woman Drinking a Glass of Water
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H20 does more for your body than anything else you could possibly consume. Considering that water ensures that your organs are performing their essential duties, it's no wonder not drinking enough of it and being dehydrated could be fatal: According to the Rehydration Project, 1.35 million people around the world die from the effects of dehydration each year.

So, what exactly happens to your body when you don't drink the suggested eight 8-ounce glasses of water a day? Keep reading to learn about all of the damage that dehydration can do to your body. And for more on how your body operates, find out What Happens to Your Body on an Airplane.

Your plasma levels decrease.

When there is an insufficient amount of water in your body, the liquid component of blood—called plasma—has less material to keep the blood cells liquified. For example, a 2008 study published in the journal Aviation, Space, and Environmental Medicine found that when healthy men were dehydrated and immobile for just four hours, their plasma volume decreased by 3.4 percent.

So why should you care about how much plasma you have? Well, without an adequate amount of plasma, your red blood cells become more concentrated. That means they also have a harder time transporting important proteins, minerals, nutrients, and oxygen to the rest of your body.

Your heart has to work overtime.

That reduction in blood volume from the decreased plasma results in the thickening of the blood. This, in turn, leads to "a decline in cardiac output, which affects the ability of our heart to supply fuel to our muscles," explains M. Ramin Modabber, MD, an orthopedic surgeon at Cedars-Sinai Kerlan-Jobe Institute in Los Angeles, California.

"In essence, our heart has to work that much harder to pump the same amount of fuel to our muscles," he says. This is why when you're dehydrated, your heart rate is typically elevated, as it's working overtime to supply blood to the rest of your body.

You get headaches.

The thickening of your blood also affects one of your other very vital organs: your brain. As this thick blood struggles to move throughout your body, it causes your blood pressure to rise. This is why, according to Modabber, dehydration sufferers typically experience headaches, particularly if they've gone without water for a longer period of time.

Your brain has to reboot.

When the brain isn't receiving the necessary amount of water, its tissue fluid decreases—and as you can imagine, this only spells trouble for your body as a whole. You're likely to struggle with memory issues and suffer from general confusion as a result of the tissue fluid decrease. Oh, and dehydration could also mean fainting spells used as a way to "reboot" your system.

"The brain does not like to be deprived of fuel [or] oxygen," says Modabber. "So when dehydration progresses, brain function slows—or if severe, it has its way of protecting itself by 'rebooting,' causing you to faint."

Your kidneys hold on to more water.

When you haven't been drinking enough water, you might notice that your trips to the bathroom become less frequent. According to Modabber, this is because dehydration triggers your kidneys to store more water in case of an emergency.

"Urinary output decreases with dehydration," explains Modabber. "The kidneys (through urine output) are the body's way of optimizing our hydration state—it can hang on to water in times of early dehydration and can also excrete water when in excess."

But if your kidneys are working in overtime for too long—and on top of that, don't receive the adequate amount of water to flush out the extra waste in your body—they will be in a world of hurt, according to the National Kidney Foundation. This lack of water can cause waste to clog your kidneys, resulting in everything from urinary tract infections to more serious issues. If you're frequently dehydrated, you're at a heightened risk of developing kidney disease, kidney failure, or low kidney function.

Your body loses its ability to regulate temperatures.

Sweating is a natural and important part of your body's temperature regulation process. The problem? When your body is starving for fluids, this regulation is completely disrupted.

"Sweating is a critical way for humans to regulate body temperature," explains Modabber. "Since sweat production decreases during dehydration in the body's effort to retain fluid, body temperature rises. This phenomenon helps to explain the decrease in muscle performance seen with dehydration."

Your skin begins to suffer.

Your body's lack of sweat production can also affect your skin. When you're dehydrated, your body only lends moisture to the more demanding areas—such as your essential internal organs—and pays less attention to the areas your body deems less vital, like the skin.

"Dry, 'saggy' skin is seen [in dehydration] and results from efforts by the body to maintain water content to vital organs and minimize water loss to 'less vital' areas," says Modabber. "Our skin is itself an organ and similar to a very thin sponge, it takes on a different appearance based on its water content." That's why drinking more water leads to more moisturized skin.

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