16 Signs and Symptoms Of Dehydration Often Overlooked

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We all know that staying properly hydrated is paramount.

But, how do you know if you are hydrating enough? What are the signs and symptoms of dehydration?

Other than feeling thirsty, there are other common signs and symptoms of dehydration that people may overlook or not associate immediately with dehydration.

In this guide to dehydration symptoms, we will discuss both the common and less common signs and symptoms of dehydration to help you quickly recognize dehydration signs in your own body so that you can rectify the problem and stay on top of your body’s hydration needs.

We will look at: 

  • 16 Signs and Symptoms Of Dehydration (That You May Overlook)
  • How to Prevent Dehydration 

Let’s get started!

A person hiking in the woods with signs and symptoms of dehydration.

16 Signs and Symptoms Of Dehydration (That You May Overlook)

Here are some of the signs and symptoms of dehydration:

#1: Muscle Twitching and Muscle Cramps After Exercise

Working in hot and humid conditions, particularly if you sweat a lot, can increase the risk of dehydration and electrolyte depletion

Electrolytes, such as sodium, potassium, magnesium, calcium, and chloride, can also become depleted after a sweaty workout because these electrolytes are excreted in sweat.

These charged particles (ions) play an essential role in helping to conduct nerve impulses and contract and relax muscles.

Even if you try to hydrate well or you are working out indoors in a climate-controlled environment, we often sweat more during exercise than we think, and some amount of dehydration can occur.

A calf muscle cramp.

Most people naturally grab a water bottle and start hydrating after exercise because they experience the thirst signal, one of the classic symptoms of dehydration.

However, there is another sign of dehydration after exercise that many people often aren’t aware is indeed a dehydration symptom: muscle twitching or muscle spasms.

Although there are other causes of muscle twitching after exercise, staying mindful of the other signs and symptoms of dehydration and low electrolyte levels after exercise can help you determine if dehydration is the reason why your muscles twitch after working out.

Note that when you exercise, and you are dehydrated, it increases the risk of heat illness because your body can’t deal with the thermal strain as well from the lack of sweating.

#2: Increased Heart Rate

One of the signs and symptoms of dehydration is an elevated heart rate, particularly during exercise.

When you are dehydrated, your blood volume drops and your body will have less blood plasma to circulate blood volume to the surface of your skin. 

When blood volume is low, your body employs mechanisms to ensure that vital organs and muscles are receiving enough blood flow so cutaneous blood circulation is reduced. 

This means that your body will not be able to capitalize on the advantages of cooling down by increasing blood flow to the surface of the skin.

A phone showing heart rate data.

Additionally, you will be sweating much more in the heat and humidity, which further contributes to blood volume loss. 

As your blood volume decreases, your heart rate has to increase in order to maintain cardiac output. This is because a lower blood volume means that your stroke volume, or the amount of blood pumped per beat of the heart, will decrease.

The faster your heart is beating, the more oxygen your heart is using and the more heat you are generating, all of which exacerbate the thermal strain on your body, further increasing your heart rate.

Plus, the resultant effort level will feel all the more challenging if your heart rate increases.

Therefore, two important signs of dehydration during exercise to be mindful of are an increase in heart rate, even if your intensity or pace is staying constant, and an increase in perceived effort level (RPE) at the same pace or intensity level.

In order to prevent dehydration during exercise, the goal needs to be to hydrate on pace with the fluid you lose through sweat.

You should find that if you are hydrating properly, your weight on the scale after your workout is within a pound or so of your weight before you head out the door. 

If your weight has dropped by more than one pound, adjust your hydration plan moving forward, keeping in mind that you need to drink an additional 16 ounces for every pound lost.

Studies also suggest that it is better to rehydrate with a beverage that contains electrolytes after exercise if you are exhibiting symptoms of dehydration.

A person covering their mouth due to bad breath.

#3: Bad Breath

A potential warning sign of dehydration is halitosis or bad breath.

When you are dehydrated, the saliva in your mouth dries up, or there is less fluid to produce saliva, giving you a dry mouth.

This allows bacteria to grow, which produces a malodorous output.

A similar phenomenon plays out with “morning breath,“ when you wake up and have a stinky mouth because saliva production decreases in the night and the body dehydrates somewhat.

Thus, bad breath can be a potential sign of dehydration, particularly if you have not just eaten something with a strong flavor profile or consumed coffee or some other substance known to cause bad breath.

Dry, cracked skin.

#4: Dry Skin

A common sign of chronic dehydration is dry skin or flaky skin.

The skin loses elasticity, and the cells shrink and lose turgidity because the cytosol—the fluid that fills the cells—becomes depleted when you are dehydrated.

In extreme cases, a symptom of dehydration is pitting edema, in which you can pinch your skin, and the skin will “tent“ or stay in its pitched fold before returning back into place because it has become sticky.

#5: Headache

Headaches can be a sign and symptom of dehydration, including headaches upon waking, during the day, or headaches after working out.

This is because the brain is about 75% water by volume, and dehydration can temporarily shrink the brain tissue, which in turn, can trigger a headache.

A person sitting at their laptop holding their head.

#6: Fatigue

Fatigue can be a dehydration symptom.

It’s important to maintain good circulation throughout your body. Blood carries oxygen and nutrients that are vital to your cells and tissues for not only proper functioning but also survival.

When you’re dehydrated, your brain and other tissues will not be as well perfused with blood, which means that the oxygen and nutrients getting to your brain, muscles, and organs decrease.

This can cause fatigue, muscle tightness, and even joint pain.

#7: Slower Brain Function

Research shows that even mild to moderate dehydration can impede focus and working memory and can cause irritability and mood swings. 

A person holding their stomach in pain.

#8: Constipation

Another one of the common signs that you are dehydrated is constipation.

When you are not drinking enough fluid, stool volume decreases, and the body tries to conserve fluid by reabsorbing more from the large intestines before fecal waste is expelled. This leads to dry, hard, shriveled stool that can be difficult to pass. 

Digestion will also slow overall if you are dehydrated, further contributing to constipation.

#9: Hunger and Sugar Cravings

Most people have heard the weight loss tip to drink more water

Being properly hydrated is not only important for maintaining the optimal health and function of every cell in your body, but it also can help you stay full, and people mistake thirst for hunger.

Plus another dehydration sign is sugar cravings, as the body needs enough fluid to break down stored glycogen into usable glucose for blood sugar.

Other common symptoms of dehydration include dark-colored urine, decreased urine output, dizziness, weakness, joint pain, nausea, and shakiness.

A person holding out a glass of water.

How to Prevent Dehydration

Even if you do your best to stay properly hydrated, almost everyone has experienced signs and symptoms of dehydration in acute situations.

However, it is important to stay on top of your hydration needs in order to prevent chronic dehydration. 

Research has found that about 75% of Americans are chronically dehydrated.

Not only is chronic dehydration associated with numerous physical and mental health consequences, but it also becomes more difficult to be aware of the signs and symptoms of dehydration if you are always in a state of being dehydrated.

Dehydration becomes your norm, so you are not aware that your body is exhibiting signs of dehydration.

According to the Institute of Medicine, women should drink at least 78 ounces (2.3 liters) of water each day, and men should drink at least 112 ounces (3.3 liters) daily. 

Fluid needs are even higher for people with a larger body size, who sweat a lot, who live in a hot climate, or who perform endurance exercises.

In cases where you are exhibiting more severe dehydration symptoms, it can also be helpful to have oral rehydration solutions with electrolytes and glucose.

Studies suggest that when glucose is consumed alongside electrolytes in fluid, fluid absorption is faster and more effective.

To help get you on track and drink more water, check out our 14-day water drinking challenge here.

A person drinking a bottle of water.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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