Dehydration and Stroke Risk: Understanding the Link

New York City isn’t known for its cool summer weather. With temperatures that routinely breach the the 90s, the city is a center of sweltering heat and intense sun. It’s also primed for a common but often ignored heat-related complication: dehydration.

Dehydration poses significant health risks and challenges for the way your body functions. What’s worse, symptoms aren’t always easy to spot — by the time you feel thirsty, dehydration is already exerting a negative impact on your health and wellness.

Our experienced providers at Advanced Medical Care are well aware of the effects of dehydration, including its impact on your risk of stroke. In this post, we review the link between dehydration and stroke and remind you of the importance of staying hydrated this summer and all year long.

Dehydration and your health

The concept of dehydration is simple: It occurs when your body loses more fluids — for instance, through urine or sweat — than it takes in. Considering that more than half of your blood is made up of fluid (plasma), it shouldn’t be surprising that even mild dehydration can have an impact on your blood volume and your circulation system.

When blood volume declines, there’s not as much blood available to carry oxygen and nutrients to your organs — including your brain — and not enough blood to carry away wastes and byproducts that can otherwise collect and cause problems. 

Blood becomes more viscous and more sluggish in your blood vessels. Thicker blood means your heart needs to work harder to maintain circulation, particularly in smaller blood vessels, including those that supply the brain. 

As circulation slows down, clot formation increases. This elevates your risk of blood vessel blockage — conditions that are directly linked to stroke risk. At the same time, lower blood volume makes it more difficult to regulate blood pressure, leading to fluctuations that interfere with blood flow, again increasing your risk of stroke.

Dehydration and your risk of stroke

There are two primary types of stroke: ischemic and hemorrhagic. The more common of the two, ischemic strokes happen when a blockage prevents your brain from receiving the oxygen-rich blood it needs to maintain normal function. Hemorrhagic strokes occur when a blood vessel in your brain bursts.

Dehydration raises the risk of both types of stroke, but particularly ischemic stroke. That’s because slow-moving blood is more prone to forming clots, including clots that block blood flow to your brain.

Dehydration also alters your body’s balance of electrolytes, substances that help regulate your heartbeat and your blood vessel function. It increases the risk of inflammation and damage in the tissue lining your blood vessels, once again increasing your risk of clots and other blockages, along with the risk of stroke.

Dehydration is dangerous at any age, but its risks tend to be greatest among older people, people with kidney problems, and men and women with heart conditions. For example, atrial fibrillation is a condition that independently increases stroke risk. 

Even healthy people can be at risk during intense exercise or during hot weather. So can people who become dehydrated due to illness.

Know your stroke risk

Stroke is a leading cause of death in the United States, but many people still don’t know what they can do to reduce their risk. Staying hydrated is a simple step everyone can take, and it’s especially important during these hot summer months.

To learn more about stroke prevention or to schedule a stroke evaluation, request an appointment online or over the phone with the neurology team at Advanced Medical Care in Forest Hills, Queens, and Brighton Beach, Brooklyn, New York.