DALLAS, Texas - As dangerous summer temperatures continue across much of the United States, the American Heart Association is urging people to take precautions, warning that extreme heat places added stress on the heart and can lead to life-threatening medical emergencies.
According to the National Weather Service, extreme heat is the leading weather-related cause of death in the United States, surpassing fatalities from hurricanes, tornadoes and other severe weather events. A report published in the Journal of the American Medical Association found that more than 2,300 people died from heat exposure in the U.S. in 2023. Additional research published in the American Heart Association's journal Circulation projects that heat-related cardiovascular deaths could more than double in the coming decades.
"Heat forces the heart to work harder," said Dr. Manesh R. Patel, volunteer president of the American Heart Association and chief of cardiology at Duke Health. "When your body is trying to cool down, your heart rate increases and your blood vessels expand. For people with heart disease, and even those who are otherwise healthy, that added strain can become dangerous quickly."
Health experts say high temperatures cause the body to sweat in an effort to cool itself, resulting in fluid loss and dehydration. At the same time, the heart must pump more blood to regulate body temperature, increasing strain on the cardiovascular system.
To reduce the risk of heat-related illness, the American Heart Association recommends avoiding strenuous outdoor activities between noon and 3 p.m., when temperatures are typically at their highest. People should wear lightweight, light-colored clothing, hats and sunglasses, use sunscreen, and drink plenty of water before, during and after spending time outdoors. Officials also advise avoiding alcohol and caffeinated beverages, which can contribute to dehydration.
The organization encourages people to take frequent breaks in shaded or air-conditioned areas and to recognize the warning signs of heat-related illness.
Symptoms of heat exhaustion include headache, cool or clammy skin, dizziness, weakness, muscle cramps, nausea, vomiting and a rapid but weak pulse. Anyone experiencing these symptoms should move to a cooler location, cool down immediately, rehydrate and seek medical attention if symptoms persist.
Heat stroke is a medical emergency. Warning signs include a body temperature above 103 degrees, hot or red skin, a rapid and strong pulse, confusion, headache, nausea or loss of consciousness. Anyone showing signs of heat stroke should receive immediate medical attention by calling 911.
Despite the risks, the American Heart Association emphasizes that regular physical activity remains essential for heart health. During periods of extreme heat, experts recommend exercising during the cooler morning or evening hours or moving workouts indoors to air-conditioned facilities. Activities such as swimming, biking, walking, gardening or walking the dog can all contribute to maintaining cardiovascular health while reducing heat exposure.
