Health

Are You Dehydrated? Don't Ignore These 19 Warning Signs

Written by Krista Bugden
Medically Reviewed by Felicia Newell, M.S., RDN

August 16, 2024

Everywhere we turn; someone is donning a Hydroflask or Stanley water bottle in an effort to stay adequately hydrated throughout their busy day. But surprisingly, merely drinking more water might not be doing as much for us as we might think.

And don’t get us wrong—our bodies need water to function properly. It’s necessary for removing waste from the body, transporting nutrients and oxygen, healthy joints, good digestion, normal blood pressure levels, optimal heart function, and countless chemical reactions in the body.

Yet, drinking just water can sometimes exacerbate your thirst even further. So, what are we talking about here? In this article, we dig into the causes of dehydration, common signs of dehydration, and everything else you should know. 

Table Of Contents

What Causes Dehydration?

You can drink half your body weight in ounces of water per day—and still be dehydrated. While this recommendation isn’t “wrong” by any means, it’s missing a few key factors.

In fact, research states, “Electrolyte content appears to make the largest contribution in hydration properties of beverages for young adults when consumed at rest.” In other words, electrolytes are a necessity if we want to ensure adequate hydration (1).

Besides not drinking enough water and electrolytes, there are other things that can contribute to dehydration.

Excessive Sweating

Whether you’re in the sauna, frequenting your favorite hot yoga class, or experiencing a hot summer day, the body loses a significant amount of water (and electrolytes) when exposed to heat—especially while exercising.

This can lead to unpleasant symptoms like dizziness, weakness, a rapid heartbeat, decreased physical/cognitive performance, and even heat exhaustion.

Catherine Gervacio, Registered Dietitian and nutrition writer for Living Fit, adds, “Many factors contribute to hydration, and it could be due to inadequate fluid intake, especially in hot weather and excessive perspiration.”

Luckily, these fluids can be easily replenished with a high-quality electrolyte powder.

NativeNote: Not all electrolyte powders are created the same. Here's what to look for (and avoid).

Diarrhea & Vomiting

Not to get grotesque, but any infection or virus that leads to vomiting or diarrhea can quickly dehydrate the body. Whether this is from the flu or simply drinking too much alcohol the night before, it’s important to try to replenish these fluids. And when nauseous, small sips might help.

Frequent Urination

Increased frequency of urination can happen due to new medications, like diuretics, excessive caffeine or alcohol consumption, or due to diseases, like uncontrolled diabetes and kidney disease. 

Urinating between four or 10 times a day is considered the norm (2). But if you’re rushing to the toilet far more than this amount, it may be worth assessing your lifestyle. Alternatively, it’s probably also worthwhile bringing up with your family doctor, especially if you suspect it’s due to medications or undiagnosed conditions such as diabetes.

Age

The two age groups most likely to experience dehydration include infants and older adults.  Infants are more likely to become dehydrated for a number of reasons, such as the inability to hydrate themselves or assess their own needs and susceptibility to diarrheal diseases (3). 

The elderly, on the other hand, are also at higher risk due to decreased thirst sensation, kidney function, and chronic illnesses or medications that increase dehydration risk (4). Thus, if we’re caring for a young child or an older adult, it’s worth knowing the signs of dehydration so we can avoid any unnecessary trips to the ER or life-threatening complications.

Environment

About half of mountaineers who brave almost-unattainable summits experience dehydration (5). This means any time you’re climbing to new heights or simply visiting a higher-altitude location (like the mountains of Colorado or Utah), fluid intake is definitely something to consider. 

So, why is dehydration more likely to happen at higher altitudes?

It comes down to water loss via respiration. At higher altitudes, if not acclimatized, our respiration rates go up. Thus, we are more likely to lose more fluid.

On top of this, many at high altitudes experience increased urination output and higher energy expenditure, further contributing to dehydration (6).

Then, there are dry and warm climates (think: Arizona, Texas, or Las Vegas). Hot climates require us to pay closer attention to our fluid intake since we inevitably sweat a whole lot more. A dry climate means the air lacks moisture, which can also lead to water loss through respiration as your body adds moisture to each breath you take.

What Are Some Common Signs of Dehydration?

Catching dehydration early is crucial to avoid life-threatening complications, like heat injury, kidney problems, seizures, and low blood volume shock (7). Pretty scary stuff. So, how can you spot the signs?

Early & Moderate Signs of Dehydration

“The feeling of being thirsty is the basic indication that the body needs to be rehydrated. Other signs include a dark urine color (dark yellow or amber), dry mouth or skin, infrequent urination, dizziness, and fatigue,” says Gervacio.

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Additional signs may include:

  • Feeling lightheaded
  • Cool skin
  • Loss of appetite
  • Swollen feet
  • Constipation
  • Lack of sweating
  • Dry cough
  • And chills (8)

Severe Signs of Dehydration

Specifically, for children, severe dehydration often means losing up to 10% of body weight (8). This requires immediate medical attention and IV fluid intervention, including the replacement of electrolytes like salt.

Signs of severe dehydration include:

  • Dark yellow urine or no urination
  • Feeling dizzy
  • Very dry skin
  • Increased heart rate
  • Increased breathing rate
  • Confusion
  • Fatigue
  • Irritability
  • Sleepiness
  • Fainting
  • Sunken eyes

NativeNote: Keep an eye out for dehydration in babies, too. They can have few or no tears when they cry and be very irritable or difficult to calm (9).

When Should I Go to the Hospital for Dehydration?

Considering the signs of early and moderate-to-severe dehydration overlap, knowing when to go to the hospital for dehydration can be a bit confusing.

Gervacio says, “If the signs above have not been resolved despite efforts to rehydrate, then it is a sign that you go to the hospital. For example, if the urine stays in a dark color despite attempts to rehydrate. Also, unquenchable thirst may indicate a more serious issue.”

However, if you or someone you know experiences any symptoms of severe dehydration, it’s important to head to the nearest ER. 

It’s also critical to pay attention to signs of heat stroke that may accompany dehydration, such as vomiting, fever, and no sweat, urine, or tear production.

Simple Tips to Prevent Dehydration

Luckily, preventing dehydration doesn’t require tons of complexities. A few preventative measures can go a long way, such as:

  • Using a reusable water bottle
  • Adding electrolytes to your water
  • Drinking half of your body weight in ounces of water per day
  • Drinking more when flying, exercising, or enduring illness
  • Paying attention to your body’s cues
  • Consuming plenty of fruits and vegetables, which are filled with water!
  • Avoiding excessive alcohol or caffeine intake

But what if you’re already dehydrated? What is the fastest way to cure dehydration? Simple: Add electrolytes to your water and drink up. As minerals with an electric charge, electrolytes are able to control the movement of fluid in and out of cells. In turn, this helps maintain fluid balance and proper hydration in the body.

And if you’re in a heated environment that is furthering the issue, move into a cool environment, if possible. 

NativeNote: Whether or not you should treat dehydration at home depends on the severity of your dehydration. Severe dehydration should always be treated by a medical professional and IV fluid intervention.

How Long Does It Take to Recover From Dehydration?

This, again, depends on the severity of dehydration. Most mild forms will recover with the correct replenishment of fluids within a few hours to one day. 

Gervacio adds, “Mild dehydration can often be addressed by increasing fluid intake and may improve within a few hours. More severe cases may take longer, and medical attention may be necessary for proper rehydration."

Frequently Asked Questions About Dehydration

Many sports drinks contain too much sugar and/or a poor ratio of electrolytes. Why would that matter? 

Well, in order to fight dehydration, your body uses something called the sodium-glucose cotransport system to rapidly replenish lost electrolytes (10). When glucose is absorbed, it helps reduce barriers in the intestines, making it easier for your body to absorb water and electrolytes like sodium. As a result, sodium makes you feel thirsty and helps your body retain water, which is super important for fighting dehydration.

Proper hydration requires a delicate balance of electrolytes and glucose, a balance that is often lacking in most sports drinks.

Krista Bugden
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Krista Bugden

Krista Bugden is a freelance writer with a BS in Human Kinetics from the University of Ottawa. She spent 5 years working as a kinesiologist, giving her the first-hand experience she needed to write well-researched, scientific, and informative blogs.

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    Medical Disclaimer

    This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Chad Walding nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement, or lifestyle program.

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