As summer temperatures soar across the United States, the American Heart Association is issuing a stark warning: extreme heat is not just uncomfortable—it 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, yet it often receives less attention than hurricanes or 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 as temperatures continue to rise.
“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.”
The body’s natural cooling mechanism—sweating—leads to fluid loss and dehydration. At the same time, the heart must pump more blood to regulate body temperature. Together, these changes place significant stress on the cardiovascular system, potentially triggering heart attacks or other cardiac events.
The American Heart Association recommends several steps to protect yourself during extreme heat. Avoid outdoor activity between noon and 3 p.m., when temperatures peak. Wear lightweight, light-colored clothing, a hat, and sunglasses, and use sunscreen. Stay hydrated by drinking water before, during, and after time outdoors, and avoid alcohol and caffeinated drinks, which can contribute to dehydration. Take frequent breaks in the shade or a cool indoor space.
Recognizing the warning signs of heat-related illness can save lives. Heat exhaustion symptoms include headache, cool and clammy skin, a fast but weak pulse, dizziness, weakness, muscle cramps, nausea, or vomiting. If you experience these, 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. Call 9-1-1 immediately if you notice a body temperature above 103°F, hot and red skin, a rapid and strong pulse, confusion, headache, loss of consciousness, or nausea. Unlike heat exhaustion, heat stroke requires urgent medical intervention.
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 like walking, swimming, biking, or gardening can still be enjoyed safely with proper precautions.
For more information on staying heart-healthy in the heat, visit heart.org.
