Heat Can Be Hazardous to Your Heart

28 July 2026

Posted in

Heart Health

With many areas of Oklahoma reaching peak summer temperatures, the INTEGRIS Health Heart Hospital and the American Heart Association (AHA) are preaching prevention.

It’s not something many people think about, but temperatures over 100 or even temperatures in the 80s with high humidity can cause a dangerous heat index that can be hard on the heart.

“In hot weather, the body tries to cool itself by shifting blood from major organs to underneath the skin,” explains Kathryn Farguson-Jayo, D.O., a cardiologist with INTEGRIS Health Cardiovascular Physicians Edmond. “This shift causes the heart to pump more blood, putting it under significantly more stress.”

Heat precautions are especially important for people on certain medications.

“Some heart medications like angiotensin receptor blockers (ARBs), angiotensin-converting enzyme (ACE) inhibitors, beta blockers, calcium channel blockers and diuretics, which affect blood pressure responses or deplete the body of sodium, can exaggerate the body’s response to heat and cause you to feel ill in extreme heat,” adds Farguson-Jayo.

She says you shouldn’t stop taking your prescriptions, but you should practice these preventive measures.

Watch the clock: It’s best to avoid the outdoors in the early afternoon (about noon to 3 p.m.) because the sun is usually at its strongest, putting you at higher risk for heat-related illnesses.

Dress for the heat: Wear lightweight, light-colored clothing in breathable fabrics such as cotton, or a newer fabric that repels sweat. Add a hat and sunglasses. Before you get started, apply a water-resistant sunscreen with at least SPF 15, and reapply it every two hours.

Drink up: Stay hydrated by drinking a few cups of water before, during and after going outside or exercising. Avoid caffeinated or alcoholic beverages.

Take regular breaks: Find some shade or a cool place, stop for a few minutes, hydrate and start again.

Follow the doctor’s orders: Continue to take all medications as prescribed.

Even if you aren’t taking medications for a heart condition, it is important to be careful in the heat. While infants and the elderly are more vulnerable to problems from heat, extreme temperatures can cause health issues for anyone.

“Staying hydrated is key. It’s easy to get dehydrated even if you don’t think you’re thirsty. Drink water before, during and after going outside in hot weather. Don’t wait until you feel thirsty,” says Farguson-Jayo. “The best way to know if you’re getting enough fluid is to monitor your urine output and make sure the urine color is pale, not dark or concentrated.”

Dehydration causes the heart to work harder, putting it at risk. Hydration helps the heart pump blood through the blood vessels to the muscles, making them work more efficiently.

If you start feeling ill effects from the heat, move to a cooler place, stop exercising and cool down immediately by dousing yourself with cold water and re-hydrating. Seek medical attention if these measures do not bring you relief.