With record-breaking temperatures already hitting much of the United States, health experts are urging the public to take precautions as extreme heat increases the risk of heart-related illnesses and deaths.

Summary: Record-breaking temperatures across the US pose significant heart health risks, with experts urging the public to take precautions. Extreme heat increases the risk of heart-related illnesses and deaths, particularly for vulnerable populations. The American Heart Association recommends staying hydrated, avoiding peak sun hours, and recognizing symptoms of heat-related conditions.

Key Takeaways:

  • Increased Risk: Extreme heat raises the risk of heart-related illnesses and deaths, with cardiovascular disease deaths potentially doubling in the next two decades.
  • Preventive Measures: Stay hydrated, avoid peak sun hours, and wear appropriate clothing to mitigate heat risks.
  • Recognize Symptoms: Learn the signs of heat exhaustion and heat stroke, and take immediate action if symptoms appear.

Summer has just begun, and record high temperatures are already being reported across much of the US—prompting the American Heart Association to warnings about taking extra precautions to stay safe in extremely high temperatures.

According to the US Centers from Disease Control and Prevention, more than 1,200 people die in the US 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 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 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.

The Impact of Heat on Heart Health

“Heat-related deaths and illnesses are mostly preventable if proper safety measures are taken,” says Joseph C. Wu, MD, PhD, 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, in a release. “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 pm) 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

Recognizing and Responding to Heat-Related Symptoms

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 rehydrating. 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

Staying Active Safely in Hot Weather

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, according to the AHA. Adjusting your activity time to early morning or later in the evening can help. 

If being outside is too much on some days, find indoor locations where you can be active, such as a shopping mall, gym, or community recreation center.

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