As summer temperatures soar across the United States, the American Heart Association is issuing a warning that extreme heat can put serious strain on the heart and increase the risk of life-threatening complications. According to the National Weather Service, extreme heat is the leading weather-related cause of death in the country, surpassing even major disasters like hurricanes and tornadoes.
A report 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. 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 the division of cardiology at Duke Health in Durham, North Carolina. “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.”
The body’s cooling mechanism relies on sweating, which can lead to fluid loss and dehydration. Simultaneously, the heart must pump more blood to regulate body temperature, placing significant stress on the cardiovascular system.
The American Heart Association recommends several steps to stay safe during extreme heat: avoid peak heat hours between noon and 3 p.m.; wear lightweight, light-colored clothing, a hat, and sunglasses; apply sunscreen; stay hydrated with water before, during, and after outdoor activities; avoid alcohol and caffeinated drinks; and take breaks in the shade or air-conditioned spaces.
Recognizing the warning signs of heat-related illness can save lives. Symptoms of heat exhaustion include headache, cool pale clammy skin, fast but weak pulse, dizziness or fainting, weakness or muscle cramps, and nausea or vomiting. Anyone experiencing these symptoms should slow down, move to a cooler place, cool down with cold water, and rehydrate; medical attention may be necessary. Heat stroke is a medical emergency requiring immediate action. Signs include body temperature above 103°F, hot red dry or damp skin, rapid strong pulse, confusion, headache, loss of consciousness, and nausea. If heat stroke is suspected, call 9-1-1 immediately.
Physical activity remains essential for heart health, even in summer. The American Heart Association suggests shifting exercise to early morning or evening hours when it is cooler, or moving workouts indoors to air-conditioned spaces. Activities such as walking, swimming, biking, skating, or gardening are beneficial. For more information, visit heart.org.
