Does Dehydration Cause Headaches?

July 1, 2024

The human body requires adequate hydration to function properly, and water plays a vital role in numerous bodily processes. Dehydration occurs when the body loses more fluids than it takes in. It can lead to various physical ailments, one of the most common being headaches. 

Headaches caused by dehydration can range from mild discomfort to severe migraines, affecting your daily activities and quality of life. Understanding the mechanisms behind this connection reveals the importance of regular fluid intake and the potential consequences of neglecting this simple yet essential aspect of health maintenance.

Why Water Is Essential to Health?

Water plays an essential role in every aspect of health and well-being. Comprising about 60% of the human body (depending on age), water is necessary for maintaining the balance and function of numerous bodily systems and conditions. 


One of the primary roles of water is maintaining homeostasis, the state of steady internal conditions maintained by living things. Water aids in regulating body temperature through perspiration and respiration, ensuring that the body operates within an optimal temperature range.

Digestive System

Water is also vital for the digestive system. It is a major component of saliva, which begins the digestive process by breaking down food. Water also facilitates the smooth passage of food through the gastrointestinal tract and is essential for dissolving nutrients and minerals, making them accessible to the body. 


Water is a key component of blood, which is made up of about 55% blood plasma. And more than 90% of that plasma is water. Blood is responsible for transporting oxygen, nutrients, and hormones to cells and removing waste products and carbon dioxide. 

Kidney Function

The kidneys, which play an important role in filtering and excreting waste products from the body, rely heavily on water. Proper hydration enables the kidneys to efficiently filter waste products and toxins from the blood, maintaining the body's electrolyte balance. Dehydration can lead to kidney stones and other renal complications.

Joints and Tissues

Water also acts as a lubricant and cushion for the body's joints and tissues. This lubrication is essential for joint movement and flexibility, reducing the risk of injuries and arthritis. 

It also helps maintain the health of the mucosal membranes, keeping the eyes, nose, and mouth moist. This is often the first line of defense for the body's immune function, helping to keep pathogens out of the body.

Brain Function

Hydration affects cognitive function and mood. Even mild dehydration can impair concentration, memory, and mood, leading to decreased cognitive performance and increased perception of task difficulty. 

Understanding Dehydration

Dehydration occurs when your body loses more fluids than it takes in, leading to an insufficient amount of water to carry out its normal functions. This imbalance disrupts the balance of minerals (salts and sugar) in your body, which can affect the way it operates. 

When you're dehydrated, your body doesn't have enough water to continue functioning the way it should, which can lead to a variety of health issues, including headaches.

The Link Between Dehydration and Headaches

The connection between dehydration and headaches is multifaceted, involving several physiological mechanisms.

Blood Volume and Brain Hydration: Dehydration leads to a decrease in blood volume, which can reduce the brain's supply of oxygen and nutrients. This reduction can cause the brain to temporarily contract or shrink from the skull, leading to pain and a dehydration headache.

Electrolyte Imbalance: Electrolytes, such as sodium and potassium, are necessary for nerve and muscle function. Dehydration disrupts the balance of these electrolytes, which can contribute to headache symptoms by affecting the nerves and muscles in the head and neck.

Vasodilation: In response to decreased blood volume, the body may attempt to increase blood flow by dilating blood vessels. This vasodilation can also contribute to headache pain.

Triggering Migraines: For individuals prone to migraines, dehydration can serve as a trigger, potentially leading to more frequent and severe migraine episodes.

Identifying Dehydration Headaches

Dehydration headaches can manifest in various ways, often described as a dull, aching pain that envelops the entire head. Some people may experience more intense pain in specific areas, such as the front, back, or sides of the head. 

Unlike tension headaches or migraines, dehydration headaches typically lack accompanying symptoms like nausea or visual disturbances. However, they may occur along with other signs of dehydration, including dry mouth, increased thirst, dark yellow urine, fatigue, and dizziness.

Prevention and Management

The key to preventing dehydration headaches lies in maintaining adequate hydration. The following strategies can help.

Regular Water Intake

Aim to drink a sufficient amount of water daily. The general guideline is 13 cups for men and 9 cups for women, with one cup equaling 8 ounces. Individual needs may vary based on factors such as climate, activity level, and overall health.

Water is the best option for hydration as energy drinks can sometimes cause dehydration due to their high sugar and caffeine levels.

In addition, filtered water can be an ideal choice. The benefits of filtered water aren't limited to simply rehydration. When aiming for sufficient daily water intake, opt for filtered water to avoid contaminants sometimes found in tap water, such as lead, pesticides, and "forever chemicals."

Monitor Fluid Loss

Pay special attention to fluid intake during hot weather, illness, or exercise, when the risk of dehydration increases due to elevated sweat production or fluid loss through fever and vomiting.

Add Water-Rich Foods to Your Diet

Consuming fruits and vegetables with high water content—such as cucumbers, tomatoes, oranges, and watermelons—can contribute to overall hydration.

Heed Thirst Signals

Thirst is a natural indicator of the body's need for fluids. Respond promptly to these cues by drinking water.

Limit Diuretics

Beverages containing caffeine or alcohol can have diuretic effects, increasing fluid loss. Moderating the intake of such drinks can help maintain hydration levels.

If you're already experiencing a dehydration headache, rehydration is the primary remedy. Drinking water can alleviate symptoms. Be sure to drink slowly rather than in large quantities at once to help your body effectively rehydrate.

When to See a Doctor

While dehydration headaches are generally not serious and can be treated at home, it's important to know when to seek medical attention. 

If your headache is severe, doesn't improve with rehydration, or is accompanied by other worrying symptoms such as fever, stiff neck, confusion, or persistent vomiting, it's crucial to consult a healthcare professional.

7 cup ready pour pitcher side view

ZeroWater 7 Cup Ready-Pour Pitcher

Stay Hydrated and Prevent Headaches

At ZeroWater, we believe you should have zero doubt about your drinking water. Our 5-stage filters not only produce purer-tasting water to help you stay hydrated, but remove 94.9% of PFOA and PFOS, and contaminants like lead and pesticides. 

You can conveniently get your water from ZeroWater pitchers or dispensers.

You can also:


"Benefits of Drinking Water" - Centers for Disease Control and Prevention - 

"Water: Essential for Your Body" - Mayo Clinic - 

"Dehydration" - Mayo Clinic - 

"Dehydration" - Mount Sinai -