Dehydration and your Heart

True or false. On a hot humid day, an active person can become dehydrated in just 15 minutes. If you guessed true, you are correct!

But what you might not realize is dehydration takes a toll on your heart. “If you are dehydrated, your blood volume decreases, so vessel walls do not stretch as much as they should,” explains cardiologist Jeffrey Shapiro, M.D., who serves on the medical advisory board for Res-Q Natural Supplements. “Pressure sensors in your blood vessels sense this and send messages to your brain to increase heart rate. For people with existing heart conditions, this spells disaster.”

Increased heart rate isn’t the only problem. Dehydration also causes high blood pressure. That’s because dehydration reduces blood volume and your body compensates by retaining more sodium, which in turn raises blood pressure. Furthermore, your blood consists of mostly water, so the amount circulating through your body decreases when you are dehydrated. This thickens the blood and makes it more difficult to effectively

circulate. All of this together compromises the amount of blood your heart pumps with each beat. That means less blood and oxygen gets pumped through your body.

Finally, if dehydration is extreme, it can cause orthostatic changes where your blood pressure actually drops quickly, leading to dizziness and lightheadedness.

So how much water do you need to stay hydrated? Some situations where you should drink more water include:

• You are exercising

• You are sweating due to heat

• You have diabetes or heart disease

• You show signs of dehydration (thirst, dark-colored urine, dry skin, fatigue, dizziness)

Take care to hydrate and you can safely enjoy the warmth summer brings.