Stay Hydrated This Summer: Your Heart Depends On It
Understanding dehydration’s effect on your cardiovascular health
As summer heats up and outdoor activities peak, it’s important to remember that staying hydrated is not just about quenching thirst. It’s critical for maintaining heart health. Dehydration can place significant, often overlooked, stress on the cardiovascular system, a risk many Americans may not fully grasp as they enjoy the warmer weather.
“Chronic dehydration forces the heart to work harder to circulate blood, significantly increasing its demand for oxygen,” according to Glenn Hirsch, MD, chief of Cardiology. “This added strain can dramatically raise the heart rate. These factors can pose a serious threat, especially for individuals with underlying heart conditions.”
Beyond the increased workload on the heart, dehydration can also thicken your blood. This increases the risk of dangerous clotting in more severe cases. “When you’re dehydrated, your blood volume decreases,” said cardiologist Minisha Kochar, MD. “Your blood gets thicker. So the risk of blood cells sticking together and forming clots increases.”
Dehydration can also deprive your kidneys of the fluid they need. Your kidneys help to manage fluid throughout the body. When they’re not functioning well, it can create problems for your heart. “If the fluid level is down in the body, the heart has to pump harder and faster to try to compensate,” said Dr. Kochar. “That increases the stress on the heart.”
Drs. Hirsch and Kochar noted some of the common signs of dehydration. “Watch for a dry mouth, feeling lightheaded or dark-colored urine,” said Dr. Hirsch. “By the time you feel thirsty, your body has likely already lost 1 to 2% of its water weight. This means you’re already behind.”
To safeguard your cardiovascular health, these hydration guidelines are essential:
- Sip Throughout the Day: Avoid “guzzling” large amounts of water. This can trigger hormones that lead to rapid urination. This is also a more inefficient way to hydrate. Small sips are key.
- Replenish Electrolytes: Excessive water intake without electrolyte replenishment can be dangerous. It leads to low sodium levels in the bloodstream. Consume salt tablets or electrolyte-rich snacks like pretzels or chips.
- Limit Caffeinated Beverages and Alcohol: Even though they’re liquids, caffeinated and alcoholic beverages are diuretics that can lead to increased dehydration. Choose water instead.
- Pre-Hydrate Before Exertion: If you anticipate heavy physical activity, consume both water and electrolytes at least four hours beforehand.
“People have this notion that they need to drink six or eight glasses of water a day. However, a lot of the water we get is in our food,” explained Dr. Hirsch. “And that’s why going by your symptoms can help you judge if you’re adequately hydrated or not.”
The importance of staying hydrated became a personal lesson for 75-year-old Rob Philippe, a patient living with a heart condition. After undergoing quadruple bypass surgery, Philippe now makes drinking water an essential part of his active life. He is now regularly taking 30-mile bike rides.
“You’ve got to stay hydrated. It’s that simple,” Philippe said. “You should always have a bottle of water in your car, a bottle of water on your bike, a bottle of water sitting on your desk.”
“Individuals with underlying heart problems or blood pressure issues face a heightened risk related to dehydration due to the extra strain it imposes on their heart,” Dr. Hirsch cautioned. “Please be mindful of your water intake. Encourage your family and friends to do the same, so everyone can safely enjoy this summer season.”
Published 7/22/25