Can Dehydration Cause High Blood Pressure? Exploring the Link

The importance of maintaining a healthy blood pressure gets a lot of attention — and rightfully so. It’s key to keeping blood flowing so it can deliver oxygen and nutrients to every nook and cranny in your body. The good news? There’s something simple you can do to assist the process and keep your blood pressure stable: Drink plenty of fluids.

Being dehydrated can cause your blood pressure to plummet and then potentially skyrocket in response. In extreme cases, this wild fluctuation could send you into a life-threatening case of shock.

When you’re dehydrated, your blood volume decreases, leading to lower blood pressure. In response, your body may constrict blood vessels to maintain blood flow to vital organs, potentially causing high blood pressure. Essentially, dehydration can disrupt the balance your body maintains for healthy blood pressure, increasing the risk of both high and low readings.

How Dehydration Causes Low Blood Pressure

Approximately 55% to 60% of your body is made of water. There’s water in your bones, muscles, and brain. Basically, there’s a splash of H2O everywhere inside of you. Not surprisingly, your blood is mostly water — which explains why it flows through your veins like a liquid and drips when you get a cut. There are usually about 5 quarts (1.25 gallons) of blood in your system.

Now, let’s talk about dehydration. When you’re dehydrated, it means that your body’s water supply is depleted. This can happen for any number of reasons, ranging from sweating a lot on a hot day to medications or simply not drinking enough. Whatever the cause, that loss of fluid is felt everywhere in your body — including blood volume. Low blood volume leads to low blood pressure, meaning your organs may not get the oxygen needed to function properly.

In the simplest of explanations, you’re just not filling up the pipes enough for what your vascular system needs. In the most extreme cases, this drop can cause heart or brain damage or even death.

Signs of Low Blood Pressure

Concerning symptoms of low blood pressure may include:

Feeling lightheaded or dizzy
Fainting or passing out (syncope)
Nausea or vomiting
Blurred or distorted vision
Fast, shallow breathing
Fatigue or weakness
Confusion or trouble concentrating

Dehydration and Low Blood Pressure

Low blood pressure is when your blood pressure reading is lower than 90/60 mm Hg. Dehydration can cause low blood pressure due to a decrease in blood volume.

Blood volume is the amount of fluid that’s circulating in your blood vessels. Maintaining a normal blood volume is necessary for blood to be able to adequately reach all of the tissues of your body. When you’re very dehydrated, your blood volume can decrease, leading to a drop in blood pressure. When blood pressure drops too low, your organs won’t receive the oxygen and nutrients they need. You could potentially go into shock.

Dehydration and High Blood Pressure

High blood pressure is when you have a systolic (top number) reading of 140 mm Hg or higher or a diastolic (bottom number) reading of 90 mm Hg or higher.

Dehydration has been linked to high blood pressure. However, research into this topic is limited. Additional work is needed to investigate the connection. Although more research is needed, it’s still worth noting that dehydration can lead to an increase in blood pressure due to the action of a hormone called vasopressin.

Vasopressin is secreted when there’s a high amount of solutes (or sodium level) in your blood, or when your blood volume is low. Both of these things can happen when you lose too much fluid. In response, when you’re dehydrated, your kidneys reabsorb water as opposed to passing it in urine. High concentrations of vasopressin can also cause your blood vessels to constrict. This can lead to an increase in blood pressure.

Symptoms of Dehydration

In addition to changes in blood pressure, there are other dehydration symptoms to look out for. Oftentimes, you’ll feel these symptoms before you know that you’ve had a change in blood pressure. These symptoms include:

Thirst
Dry mouth
Urinating less often
Urine that’s dark in color
Feeling tired or fatigued
Lightheadedness or dizziness
Confusion

Additionally, children who are dehydrated may have the following symptoms:

No wet diapers for several hours
Absence of tears when crying
Irritability
Sunken cheeks, eyes, or soft spot on the skull (fontanel)
Listlessness

Causes of Dehydration

Other than not drinking enough fluids, there are other possible causes of dehydration. They can include:

Illness. A high fever can lead to dehydration. Additionally, vomiting and diarrhea can lead to a significant loss of fluids and electrolytes.
Increased sweating. Water is lost when you sweat. An increase in sweating can occur in hot weather, during exercise, and if you’re sick with a fever.
Frequent urination. You can also lose fluids through urination. Medications like diuretics, underlying conditions such as diabetes, and alcohol consumption can all cause more frequent urination.

How Much Water Should You Drink Each Day?

The key to preventing dehydration is to make sure you take in enough fluid each day. But how much water or other fluids should you drink in a day? Daily fluid recommendations can depend on several factors, including things like:

Age
Sex
Weight
Your overall health
Weather conditions
Activity level
Pregnancy or breastfeeding

A good goal to aim for is to drink at least eight glasses of water a day. If you find it hard to drink plain water, you can also stay hydrated by drinking:

Water infused with slices of fruit, like lemon or cucumber
Sugar-free sparkling water
Smoothies made with fruits and vegetables
Decaffeinated herbal tea
Milk
Low sodium soups

Also, remember that you can get water from some food sources, particularly fruits and vegetables. Additionally, follow the tips below to help yourself stay hydrated:

Always drink when you feel thirsty. Feeling thirsty is your body’s way of telling you that you need more fluids.
Remember to drink more water when you’re being physically active, in a hot climate, or ill with a fever, vomiting, or diarrhea.
Carry a water bottle with you as you go about your daily activities. That way you’ll always have water on hand.
Choose water instead of sugary sodas, energy drinks, sweetened beverages, or alcoholic drinks.

The Bottom Line

Changes in blood pressure can occur due to dehydration. A drop in blood volume can lead to a potentially dangerous drop in blood pressure and even shock. High blood pressure has also been linked to dehydration, although more research is needed to understand the connection fully. You can prevent dehydration by drinking plenty of fluids. This is especially important if you’re ill, in a warm environment, or being physically active.

Remember, staying hydrated is not just about drinking water; it’s about maintaining a balance that keeps your entire

At Tri-State Healthcare Clinics, we offer comprehensive services to help you manage your blood pressure effectively. Our expert team provides personalized care and guidance to keep you hydrated and healthy.

Don’t wait—take the first step towards better blood pressure management. Book an appointment with us today!