The American Heart Association is alerting the public that soaring summer temperatures pose a serious threat to cardiovascular health, as extreme heat forces the heart to work harder and increases the risk of life-threatening complications. Although hurricanes and tornadoes often dominate news coverage, extreme heat is the leading weather-related cause of death in the United States, according to the National Weather Service.
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 Manesh R. Patel, M.D., FAHA, volunteer president of the American Heart Association and chief of the division 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.”
When temperatures climb, the body sweats to cool itself, leading to fluid loss and dehydration. At the same time, the heart must pump more blood to regulate body temperature, putting significant stress on the cardiovascular system.
The American Heart Association recommends taking simple but important steps to stay safe: avoid peak heat hours between noon and 3 p.m.; wear lightweight, light-colored clothing and a hat; stay hydrated with water and avoid alcohol and caffeinated drinks; take breaks in the shade or cool indoor spaces; and know the warning signs of heat exhaustion and heat stroke.
Heat exhaustion symptoms include headache, cool and clammy skin, fast but weak pulse, dizziness, weakness, muscle cramps, and nausea. If these occur, individuals should move to a cooler place, cool down with cold water, and rehydrate. Heat stroke is a medical emergency—call 9-1-1 immediately if body temperature exceeds 103°F, skin is hot and red, pulse is rapid and strong, or confusion or loss of consciousness occurs.
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’s cooler, or moving workouts indoors to air-conditioned spaces. Activities like walking, swimming, biking, and gardening are recommended but should be done with caution during extreme heat.
For more information on staying heart-healthy in the heat, visit heart.org.
