DALLAS, June 20, 2024 — It’s only the first day of summer and record high temperatures are already being reported across much of the U.S. That’s prompted the American Heart Association, celebrating a century of lifesaving service as the world’s leading nonprofit organization focused on heart and brain health for all, to issue important warnings about taking extra precautions to stay safe in extremely high temperatures.

According to the U.S. Centers for Disease Control and Prevention, more than 1,200 people die in the U.S. each year as a direct cause of extreme heat. That number is rising substantially – as is the number of people dying from heat related-cardiovascular disease. A study recently published in the American Heart Association’s flagship, peer-reviewed journal Circulation predicts that cardiovascular disease deaths related to extreme heat may more than double over the next two decades.

Heat and dehydration cause the heart to work harder putting it under significant stress. Several recent studies shed insight on to what that can do to heart health:

  • Preliminary research presented at the American Heart Association’s Epidemiology and Prevention/Lifestyle and Cardiometabolic Scientific Sessions 2024 found that short-term exposure to higher heat may increase inflammation and interfere with normal immune system functions in the body, which may, in turn, increase susceptibility to infections and accelerate the progression of cardiovascular disease.
  • The combination of soaring heat and smothering fine particulate pollution may double the risk of heart attack death according to another study published in Circulation.

“Heat-related deaths and illnesses are mostly preventable if proper safety measures are taken,” said Joseph C. Wu, M.D., Ph.D., FAHA, current volunteer president of the American Heart Association, director of the Stanford Cardiovascular Institute and the Simon H. Stertzer Professor of Medicine and Radiology at Stanford School of Medicine. “Precautions are especially important for infants and older adults and people with high blood pressure, obesity or a history of heart disease or stroke. While some people are more vulnerable to problems from heat, extreme temperatures can cause health issues for anyone.”

Wu suggests that everyone follows these hot weather precautions:

  • Watch the clock: It’s best to avoid the outdoors in the early afternoon (about noon to 3 p.m.) because the sun is usually at its strongest, putting you at higher risk for heat-related illnesses.
  • Dress for the heat: Wear lightweight, light-colored clothing in breathable fabrics such as cotton, or a newer fabric that repels sweat. Add a hat and sunglasses. Before you get started, apply a water-resistant sunscreen with at least SPF 15, and reapply it every two hours.
  • Drink up: Stay hydrated by drinking a few cups of water before, during and after going outside or exercising. Avoid caffeinated or alcoholic beverages.
  • Take regular breaks: Find some shade or a cool place, stop for a few minutes, hydrate and start again

It’s important to know the signs and symptoms when you may be experiencing too much heat.

Symptoms of heat exhaustion:

  • Headaches
  • Cool, pale and moist skin
  • Fast, weak pulse
  • Dizziness and light-headedness
  • Weakness or muscle cramps
  • Nausea and vomiting
  • Passing out

If you experience these symptoms, move to a cooler place, stop exercising and cool down immediately by dousing yourself with cold water and re-hydrating. You may need to seek medical attention.

Heat stroke is a medical emergency, if you experience these symptoms call 9-1-1 and get medical attention right away.

Symptoms of heat stroke:

  • High body temperature (103 degrees Fahrenheit or higher)
  • Hot, red, dry or damp skin
  • Fast, strong pulse
  • Headache, dizziness and confusion
  • Nausea
  • Passing out

While being heart-smart in the heat, it’s still important to find ways for the whole family to stay active even during the high temperatures of summer. Try walking, swimming, biking, skating, jumping rope, building a backyard obstacle course, or organizing a neighborhood soccer game. Even gardening, pushing a stroller or walking the dog counts. Adjusting your activity time to early morning or later in the evening can also help. If being outside is just too much on some days, find indoor locations where you can be active, such as a shopping mall, gym or community recreation center.

Learn more about how heat can affect your heart health at heart.org.

Additional Resources:

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About the American Heart Association 

The American Heart Association is a relentless force for a world of longer, healthier lives. We are dedicated to ensuring equitable health in all communities. Through collaboration with numerous organizations, and powered by millions of volunteers, we fund innovative research, advocate for the public’s health and share lifesaving resources. The Dallas-based organization has been a leading source of health information for a century. During 2024 - our Centennial year - we celebrate our rich 100-year history and accomplishments. As we forge ahead into our second century of bold discovery and impact our vision is to advance health and hope for everyone, everywhere. Connect with us on heart.org, Facebook, X or by calling 1-800-AHA-USA1.    

For Media Inquiries and AHA/ASA Expert Perspective: 214-706-1173

Cathy Lewis: 214-706-1324, cathy.lewis@heart.org

For Public Inquiries: 1-800-AHA-USA1 (242-8721)

heart.org and stroke.org