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blood pressure dehydration

Did You Know There's a Connection Between Blood Pressure and Dehydration?

December 22, 2023

By Moses Osoro, MD

It's no secret that staying hydrated has many health benefits, from regulating your body temperature and lubricating your joints to protecting your kidneys. But did you know there’s a connection between staying hydrated and keeping your blood pressure numbers in check?


Understanding Blood Pressure

Before diving into how being adequately hydrated can help maintain healthy blood pressure, it's essential to understand what blood pressure is and how to interpret the numbers.

Blood pressure is the force exerted by circulating blood against the wall of the arteries. It has two components: systolic pressure (the pressure recorded when your heart beats) and diastolic pressure (when your heart is resting between beats.)

Having a healthy blood pressure is crucial for achieving optimal cardiovascular health, and a blood pressure reading that’s above or below the norm can result in serious health issues, including shock, heart disease, and stroke.

The Connection Between Dehydration and Blood Pressure


If you’re dehydrated, your body will lose more fluid than it takes in, leading to an imbalance of electrolytes. You might become dehydrated for several reasons, including sweating on a hot day, taking certain medications, or not drinking enough water.

As a result of dehydration, your blood volume decreases, causing your heart to work harder to pump more blood and leading to elevated blood pressure readings.

Dehydration also triggers the release of a hormone known as vasopressin, which causes your body to retain water. Vasopressin can prompt blood vessels to tighten or constrict, causing your blood pressure to rise. If you’ve already been diagnosed with high blood pressure, or are at risk of developing it, dehydration can make the condition worse and more challenging to manage.

Dehydration can also cause a drop in blood pressure, defined as having a systolic reading lower than 90 mm Hg and a diastolic reading of 60 mm Hg.

If your blood volume decreases because you're dehydrated, your blood pressure can plummet. Should it dip too low, your vital organs won't receive the oxygen and nutrients they need and you could go into shock.

Tips for Maintaining Your Hydration Levels

Below are some suggestions to ensure you stay adequately hydrated, which may, in turn, help keep your blood pressure at an optimal reading:

  • Be sure you’re drinking enough healthy fluids: The amount of water you should drink can vary, based on factors such as age, weight, activity level, and climate. A commonly recommended guideline is eight 8-ounce glasses of water per day, totaling about 2 liters or half a gallon. However, this number is individualized depending on different scenarios. For example, someone with congestive heart failure needs to limit fluid intake to 1.5 liters daily. On the other hand, someone doing a lot of physical activity or working outdoors and losing water through sweat will need to increase their fluid intake. In general, most aren’t drinking enough water, and the general six to eight glasses per day recommendation will work.
  • Monitor your sodium intake: Consuming excessive sodium can contribute to dehydration and may increase your blood pressure. One way to curb your sodium intake is to be mindful of choosing fresh, whole foods over those that are overly processed or contain high amounts of salt.
  • Incorporate hydrating foods: Many fruits and vegetables contain high water content, which can help you stay hydrated. Watermelon, cucumbers, and celery are all excellent choices to consider.
  • Limit caffeine and alcohol: Caffeine and alcohol have diuretic effects, leading to increased fluid loss. Limiting the number of caffeinated and alcoholic beverages you consume can help keep you hydrated and may help keep your blood pressure numbers where they need to be.

The connection between hydration and blood pressure serves as a reminder of the holistic nature of our health and how the different systems work with and depend on each other to keep our bodies working as they should. By understanding hydration's impact on blood pressure, we empower ourselves to make conscious choices that benefit our cardiovascular well-being. So, the next time you reach for that glass of water, remember that you’re quenching your thirst and also doing a world of good for your cardiovascular system.

Portrait of Moses Osoro, MD, Cardiology specialist at Kelsey-Seybold Clinic.

About the Author

Dr. Osoro is a cardiologist who cares for patients at Kelsey-Seybold’s Kingwood Clinic and The Woodlands Clinic. His clinical interests include the treatment and prevention of coronary artery disease, treatment and management of valvular disease, and diagnosis and treatment of arrhythmias.
Dr. Adesina from Kelsey-Seybold Clinic

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