How Heat Affects Heart Health: What You Need to Know in High Temperatures

When temperatures climb, it’s not just your comfort that’s at stake—your heart could also be under strain. Extreme heat can put added pressure on the cardiovascular system, especially for people living with heart disease or other heart conditions. Understanding the connection between heat and heart disease can help you take smart steps to protect yourself.

Norman Regional interventional cardiologist, Archana Gautam, MD, explains how hot weather impacts the heart, early warning signs to watch for, and the best ways to stay safe.

How Extreme Heat Impacts the Heart

“When you spend long periods in high temperatures, your arteries can widen, lowering your blood pressure. To keep blood flowing, your heart works harder, often beating faster,” said Dr. Gautam.

“This can lead to dizziness, lightheadedness, and palpitations. If dehydration sets in, electrolyte levels drop as well, increasing the risk of irregular heart rhythms such as atrial fibrillation. In serious cases, thickened blood from dehydration can even lead to a stroke or heart attack.”

Why People With Heart Disease Are More Vulnerable

For people with existing heart conditions, the dangers are greater. Certain medications—like beta blockers or diuretics—can interfere with the body’s ability to respond to heat, either by preventing the heart rate from increasing as needed or by speeding fluid loss.

“If you have congestive heart failure, the risk is higher still, as dehydration can happen faster and may impact kidney function. Those with blocked arteries may also struggle to tolerate the stress heat places on the body,” said Dr. Gautam.

To lower the risk, Dr. Gautam recommends limiting outdoor activities to cooler times of day, such as early mornings or after sunset, and staying consistently hydrated.

Early Warning Signs of Heat-Related Heart Stress

Recognizing the symptoms of heart problems and heat early can prevent serious complications. Watch for:

• Dizziness or lightheadedness
• Weakness or fatigue
• A rapid or fluttering heartbeat
• Shortness of breath
• Confusion or trouble thinking clearly

If you notice these signs, stop activity immediately, get indoors, and cool down. If symptoms persist, seek medical attention.

Protecting Your Heart in Hot Weather

“If you’re working or exercising outside, plan your activity around cooler hours. Drink water before, during, and after being in the heat, and take breaks in shaded or air-conditioned spaces. People without congestive heart failure may benefit from adding electrolytes to replace lost minerals, but those with CHF should stick to plain water to avoid fluid overload,” said Dr. Gautam.

Who’s Most at Risk

Heat-related heart complications are more common in certain groups:

• Adults over 65
• Children under 15
• People with heart disease, high blood pressure, or irregular heart rhythms
• Those with kidney problems

Each year, thousands of heat-related deaths occur in the U.S., and many are linked to underlying heart conditions.

When to Seek Emergency Care

Call 911 right away if you experience severe symptoms such as fainting, a rapid heartbeat of 130–140 beats per minute, chest pain, or confusion while in the heat. Quick medical attention can make the difference between recovery and a serious complication.

Bottom line: Hot weather can do more than make you sweat—it can put your heart in danger. By staying hydrated, avoiding peak heat, and paying attention to warning signs, you can greatly reduce your risk of heat-related heart problems.

To learn more about Dr. Gautam and Norman Regional Heart & Vascular Associates, visit here.