As summer temperatures soar across the United States, the American Heart Association is alerting the public that extreme heat can seriously strain 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 hurricanes and tornadoes in fatalities.
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 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 physiological mechanism involves sweating to cool the body, which leads to fluid loss and dehydration. Simultaneously, the heart must pump more blood to regulate body temperature, placing significant stress on the cardiovascular system.
To protect against heat-related heart risks, the American Heart Association recommends avoiding outdoor activity between noon and 3 p.m., when temperatures peak; wearing lightweight, light-colored clothing, a hat, and sunglasses; staying hydrated with water and avoiding alcohol or caffeinated drinks; and taking breaks in shade or air-conditioned spaces.
Recognizing warning signs is critical. Symptoms of heat exhaustion include headache, cool and clammy skin, fast but weak pulse, dizziness, weakness, nausea, or vomiting. Individuals should move to a cooler place, cool down with cold water, and rehydrate. Heat stroke is a medical emergency, indicated by body temperature above 103°F, hot and red skin, rapid strong pulse, confusion, or loss of consciousness; immediate medical attention is necessary.
Physical activity remains important for heart health even in summer. The American Heart Association suggests shifting exercise to early morning or evening hours or moving workouts indoors to air-conditioned spaces. Activities such as walking, swimming, biking, or gardening are beneficial, but caution is advised.
“Learn more about staying heart-healthy in the heat at heart.org,” the organization stated. The American Heart Association, supported by more than 35 million volunteers globally, funds research, advocates for public health, and provides resources to combat cardiovascular disease and stroke.
