Written by Dr. Savannah Muncy, Pharm.D on
October 19, 2022
Reading Time: 7 minutes

Medically Reviewed by our Medical Affairs Team

Written by Dr. Savannah Muncy, Pharm.D on:

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Do you ever feel like your head is in a fog? Like you can’t think straight, and everything is just a little bit harder than it should be? Chances are, if you’re feeling this way, you’re dehydrated.

Dehydration can lead to all sorts of problems, including brain fog.

In this article, we’ll discuss what dehydration is, the signs and symptoms of being dehydrated, and how dehydration can lead to brain fog.

We’ll also provide some tips on how to stay hydrated and avoid dehydration-related brain fog.

Let’s get started!

What is dehydration, exactly?

Dehydration occurs when your body does not have enough fluid or if your water intake is a lot less than normal.

This can be due to not drinking enough fluids, losing too much fluid through sweating or urination, or having a condition that prevents your body from retaining fluid.

Being dehydrated can lead to a number of problems, including brain fog. In more severe cases, it can lead to heat stroke, kidney stones, seizures, and coma.

Common Causes

There are a number of things that can cause dehydration, including:

  • not drinking enough water
  • excessive sweating
  • urinating too often
  • vomiting
  • diarrhea
  • high fever
  • strenuous exercise
  • hot weather

Common Signs and Symptoms

Being dehydrated can cause a number of different symptoms, including:

  • thirst
  • dry mouth
  • tiredness
  • physical and mental fatigue
  • dizziness
  • headache
  • confusion (a.k.a., brain fog)
  • lightheadedness
  • darker than usual urine color

These symptoms can range from mild to severe, depending on how dehydrated you are.

Who is at risk of being dehydrated?

Anyone can become dehydrated, but some people are at a higher risk than others. This includes:

Babies and young children

Infants and young children are at a higher risk of being dehydrated because their bodies are made up of a greater percentage of water than adults.

They also have a higher surface area to body weight ratio, which means they lose fluid more quickly.

Older adults

As we age, our bodies become less efficient at retaining water. Older adults are also more likely to have chronic medical conditions that can lead to being dehydrated, such as diabetes.


Athletes, particularly those who participate in endurance sports, are at a higher risk of dehydration. This is because they lose fluid through sweating and often don’t replace it quickly enough.

People with certain medical conditions

Certain medical conditions can put you at a higher risk of being dehydrated. These include diabetes, heart failure, and kidney disease.

People who live in hot climates

If you live in a hot climate, you’re at a higher risk of being dehydrated because you lose fluid through sweating.

People who just don’t like drinking plain water

If you don’t drink water because you dislike the taste of it or you’re just not used to drinking it, you’re at a higher risk of being dehydrated, especially if you’re an avid drinker of alcohol, caffeinated, and sugary drinks.


Dehydration can lead to a number of different complications, including:

Heat injury

If you become dehydrated while exercising in the heat, you’re at a higher risk of heat injury. This can range from heat cramps to heat exhaustion to potentially fatal heat stroke.

Symptoms indicating heat exhaustion are, but are not limited to, dizziness, headache, and nausea. Muscle cramps may also be present.

Treatment for heat exhaustion includes removal from the heat, rest, and taking fluids. If left untreated, heat exhaustion can lead to heatstroke, which is a potentially fatal condition.

Urinary tract infections

Being dehydrated can lead to urinary tract infections because it concentrates the urine and makes it more likely for bacteria to grow.

Also, being dehydrated will not only make it more likely for you to get a UTI but can also worsen the pain felt by those who already have one.

In order to prevent or reduce chronic UTIs, consult with your doctor and follow these tips:

  • Wipe front-to-back
  • Urinate before and after intercourse

Kidney stones

Being dehydrated can also lead to kidney stones. This is because when there’s not enough fluid in the human body, urine becomes concentrated, and minerals can start to crystallize.


Dehydration can cause seizures, particularly in children. This is because being dehydrated can cause a drop in blood pressure and electrolyte imbalances.


In serious cases, dehydration can lead to coma. This is usually due to a severe electrolyte imbalance or a fatal drop in blood flow.

Low blood volume shock (hypovolemic shock)

Being dehydrated can cause low blood volume shock, which is a medical emergency. This happens when there’s not enough fluid in the body to maintain blood pressure and circulation.


Being dehydrated must be treated by replenishing the fluid level in the body.

This can be done by consuming clear fluids such as water, clear broths, frozen water, ice pops, or sugar-free drinks that are high in electrolytes.

Some dehydrated patients, however, will require intravenous fluids in order to rehydrate.

Oral rehydration solutions (ORS) are a type of fluid that contains water, salts, and glucose. They’re used to treat dehydration caused by diarrhea, particularly in children.

ORS can be bought at pharmacies or made at home using WHO-recommended recipes.

To make an oral rehydration solution at home, you’ll need the following:

  • 1 liter of safe drinking water
  • 8 teaspoons of sugar
  • 1/2 teaspoon of salt

Mix all ingredients together until they’re fully dissolved, and frequently drink, especially during bouts of diarrhea. It’s important to note that ORS is not a replacement for fluids lost through vomiting.

If you’re unable to keep fluids down, it’s important to seek medical attention.

Being dehydrated is a serious condition that can lead to a number of complications, some of which can be fatal. It’s important to take steps to prevent dehydration, particularly if you’re at a higher risk.

If you think you may be dehydrated, it’s important to seek medical attention because being dehydrated can quickly become a medical emergency.


There are a number of things you can do to prevent being dehydrated, including:

  • Make it a habit to drink a glass of water the moment you wake up.
  • Drink plenty of fluids, especially water, throughout the day.
  • Avoid beverages that contain caffeine or alcohol.
  • Increase your fluid intake when you’re ill, particularly if you have diarrhea or are vomiting.
  • Increase your fluid intake when you’re exercising or in hot weather.
  • Drink oral rehydration solutions if you have diarrhea.
  • Take breaks and often rest if you’re working in a hot environment.
  • Wear loose, light clothing when it’s hot outside.
  • Check your urine color regularly. If it’s dark yellow, you may be dehydrated.
  • Check your urine output. If you’re urinating less than usual, you may be dehydrated.
  • Pay attention to thirst. If you’re thirsty, you may already be dehydrated.
  • Check for other signs and symptoms of dehydration, such as fatigue, dizziness, headache, or brain fog.

If you think you or someone else may be dehydrated, it’s important to seek medical attention immediately because being dehydrated can rapidly turn into a medical emergency if not treated properly.

How does dehydration affect the brain?

Being dehydrated can cause a number of problems, and one of the most serious is its effect on the brain, especially brain cells.

Studies show that being dehydrated can cause confusion, dizziness, and fatigue. It can also lead to more serious problems such as seizures, coma, and even death.

One study also shows that being dehydrated can cause a decrease in brain volume.

Another study shows that even mild dehydration can affect brain function. Just a 1% drop in hydration levels can lead to a 5% decrease in cognitive function. A 2% dehydration rate causes short-term memory loss and impairs math skills.

Coping with Dehydration Brain Fog

Here are a few steps you can take when you’re experiencing both dehydration and brain fog:

Drink as much water as you need

Contrary to popular belief, drinking 8 glasses of water a day may not be enough, especially if you live in a location with more heat and humidity or you have more physical activity and are sweating than an average person.

So, drinking as much water as you need is crucial. You need to drink enough water so that your urine is light yellow or clear.

If you’re working out, be sure to drink even more water than usual, as you’ll be sweating and losing fluids at a higher rate.

You can also check your hydration level by looking at the color of your urine. If it’s dark yellow, you’re likely dehydrated.

Drink electrolyte-rich fluids

Fluids that contain electrolytes, such as sports drinks and natural fruit juices, can also help you recover from dehydration and brain fog more quickly.

This is because electrolytes are essential for proper hydration, and they help regulate fluid balance in the body.

Some electrolytes, such as sodium and potassium, are lost at higher rates when you sweat. So replenishing them can help you to rehydrate more effectively.

However, it’s important to note that sports drinks are high in sugar, so they should only be consumed in moderation.

Avoid drinks that may worsen brain fog.

While being dehydrated can cause brain fog, certain drinks can also make it worse. These include:

  • Caffeinated beverages: Caffeine is a diuretic, which means it causes you to lose more fluids than you take in. So drinking caffeinated beverages can actually make dehydration worse.
  • Alcohol: Alcohol is also a diuretic, and it can lead to being dehydrated. In addition, alcohol consumption can interfere with your body’s ability to rehydrate itself effectively.
  • Sugary drinks: Sugary drinks can actually make being dehydrated worse because they cause your body to lose fluids more quickly. They can also contribute to brain fog by causing a sugar crash.

So, it’s important to avoid these drinks if you’re trying to cope with dehydration and brain fog.

Get plenty of rest

Being dehydrated can cause fatigue, so it’s important to get some rest when you’re feeling tired.

Resting will help your body to recover from being dehydrated and will also give you the energy you need to focus and concentrate.

When you’re dehydrated, your body needs time to recover and rehydrate itself. So, it’s important to get plenty of rest.

This means not only getting enough sleep at night but also taking breaks during the day to rest and relax.

If you can, take a nap or lie down for a few minutes to give your body a chance to recover.

In addition, try to avoid strenuous activity when you’re dehydrated. This can make dehydration and brain fog worse.

Eat hydrating foods

In addition to drinking plenty of fluids, you can also help yourself recover from being dehydrated by eating hydrating foods.

Some of the best foods for being dehydrated are:

  • Watermelon: This fruit is more than 90% water and is rich in electrolytes.
  • Celery: Celery is high in water and electrolytes. It also contains vitamins A, C, and K.
  • Cucumber: Cucumbers are about 96% water. They’re also rich in vitamins B and C.
  • Spinach: Spinach is around 92% water and is a good source of vitamins A, C, E, and K.
  • Tomatoes: Tomatoes are around 94% water and are rich in vitamins A, C, and K.

In addition to these foods, you can also try eating soups and stews, as they’re often packed with hydrating vegetables.

Use a humidifier

If the air in your home or office is dry, it can make being dehydrated and having brain fog worse.

A humidifier can help to add moisture to the air and can make it easier to breathe. This can help to reduce the symptoms of dehydration and brain fog.

In addition, a humidifier can also help to relieve congestion and coughing.

If you don’t have a humidifier, you can try boiling a pot of water on the stove and placing it in your room to add moisture to the air.

Concluding Thoughts

Dealing with dehydration and brain fog can be overwhelming and debilitating. Your daily tasks can become more difficult than usual, or worse; you might end up in a medical emergency.

People who have been experiencing dehydration brain fog find it increasingly difficult to focus, remember things, and make decisions.

Thankfully, there are steps you can take to alleviate the symptoms and improve your overall well-being, especially your brain health.

So, make sure that you’re adequately hydrated throughout the day to reap the mental benefits of hydration.

If you want to learn more about clearing brain fog naturally and improving your cognitive function, in the long run, check out these helpful resources in our blog


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