Dehydration and Blood Pressure

by Susan Schachter August 09, 2022 2 min read

Dehydration and Blood Pressure

Wow, it’s been hot! How hot has it been? Well, according to the EPA the number of heat waves (with the one exception of the “Dust Bowl” in the 1930s) has been steadily increasing in frequency and duration in major cities across the U.S. every decade since the 1960s. What does this mean for our health and in particular, for our blood pressure? Appropriate hydration is imperative!

When temperatures are high the body uses it's fluids in the form of perspiration to cool us off and attempt to keep our internal temperature in a normal range. When this is occurring, we must make an effort to replenish those fluids so that we can avoid becoming dehydrated. We’re addressing dehydration due to external temperature in this Circulatory but it can also be caused by illness, fever, frequent urination, and excessive sweating.

Can Dehydration Cause High Blood Pressure?

Being dehydrated creates a situation in which our blood volume decreases and our body retains more sodium which thickens our blood and makes it more difficult to pump. This decrease in blood volume/increase in blood thickness makes the rate and pressure at which our heart needs to pump increase in an effort to distribute blood throughout our body. In other words, it can create high blood pressure.

When the body is appropriately hydrated, the heart doesn’t have to work as hard to effectively pump blood.

How can we avoid becoming dehydrated? Our body’s thirst mechanism is not particularly reliable. We usually experience thirst when we’ve already not been meeting our fluid needs for a while. Because of this and the extreme heat we’ve been experiencing this summer, it is of particular importance to be proactive about our fluid intake.

The recommended amount of fluid intake per day from beverages and foods that contain water are as follows:

For Women:

Approximately 11 cups (91 oz)

For Men:

Approximately 15 cups (125 oz)

Water is what should make up the MAJORITY of our fluid intake. Other beverages can be a part of our intake, although some beverages such as high caffeine content beverages and alcohol can be dehydrating. It’s also worth noting that energy drinks and high sugar content drinks like soda are particularly bad in terms of hydration status and hypertension.

It’s good to know that high-water content foods count in our contribution to our fluid intake.

Here are some foods that contain a decent amount of water:

Watermelon – 1 cup contains 5 oz of water
Baked Potato – 1 medium contains 4.5 oz of water
Tomato – ½ cup contains 3 oz of water
Cooked Brown Rice – ½ cup contains 2.5 oz of water
Kidney Beans – ½ cup canned (drained) contains 3 oz of water
Apple – 1 medium contains 5.5 oz of water
Yogurt – 1 cup of fat-free vanilla contains 6.8 oz of water

By deliberately paying attention to how much fluid we’re taking in, we can avoid having a negative impact on our blood pressure due to dehydration. Our hydration status is always important but it’s especially important right now during these heat waves!

Here’s to your health!


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