Skip to main content

Climate change, heat waves affect heart health, experts say. Here's why that puts people of color at higher risk.

Show Caption

Martha Gabriel knows the effects of sweltering heat. For the last five years, Gabriel has been picking sweet potatoes, beans and tomatoes under the blazing South Florida sun.

One scorching summer day while working at a plant nursery, her heart began beating rapidly. Her breathing turned heavy, and she felt faint.

“I didn’t want to go home. I needed to work and buy food. I didn’t want to lose hours,” Gabriel, 41, said in Spanish through an interpreter. Gabriel is pregnant and has prediabetes. She worries for the health of her heart, her baby as well as her husband, a landscaper.

A few years ago, Jose Delgado, a 72-year-old farm worker who also picks sweet potatoes, had a health episode in Homestead, Florida. During a hot day in May, his vision suddenly started to blur, and his muscles cramped. He had a throbbing headache.

"But I kept working. I don't receive support or benefits, so I have to work to survive," he said. He then collapsed, and was hospitalized for several days with kidney failure.

But if he'd waited a few more minutes to get to the hospital, doctors told him, he would have died.

Climate change is 'threat multiplier' for people of color

The climate continues to warm and the nation has been enduring record heat waves. People of color disproportionately suffer from excessive heat, and the health outcomes linked to it, experts say.

A Centers for Disease Control and Prevention study found Indigenous people had the highest rates of heat-related deaths, followed by Black people.

Researchers are finding that extreme heat and air pollution have major effects on cardiovascular health, and heat-related deaths and hospitalizations have been linked to cardiovascular disease.

The Biden administration announced Sept. 20 it will implement new enforcement measures to protect indoor and outdoor workers from extreme heat through the Occupational Safety and Health Administration.

Overrepresented in outdoor work, people of color suffer disparate rates of heart disease and are more likely to live in warmer, more polluted areas, studies show. The factors combined put them at higher risk from extreme heat events brought on by climate change, experts say.

“There’s a lot of evidence that points to heat clearly impacting those with underlying heart problems, and making those worse, and it’s concerning that certain communities of color also have disproportionately high rates of certain heart-related conditions," said  Dr. Renee Salas, an emergency medicine physician at Massachusetts General Hospital who specializes in climate and health.

She called climate change a "threat multiplier."

More: People of color face disproportionate harm from climate change, EPA says

"It makes existing problems worse and so it’s worsening these existing trends, but it also is creating new problems, and worsening existing disparities and creating new disparities," she said.

Black people are 30% more likely to die of heart disease than white people, according to the CDC. Hispanic people are more likely to have risk factors for heart disease such as obesity and diabetes than white people.

Similarly, Indigenous people are more likely to be obese and have high blood pressure, 50% more likely to be diagnosed with coronary heart disease than white people.

These conditions, combined with lack of access to health care and other resources, put sufferers at higher risk of heat-related illness, Dr. Catherine Toms, a physician and committee member at the Florida Clinicians for Climate Action, said during an online seminar. Pregnant people like Gabriel are also at higher risk.

"We already experience and will continue to see more frequent, more severe and longer heat waves," said Toms. "Outdoor workers are on the frontlines. If we fail to prepare, we can expect to see more emergency room visits, hospitalizations and deaths related to heat stress."

Living in hotter climates can bring higher health risk

Where a person lives also contributes to their risk.

A recent study published in Nature Communications found in major U.S. cities, the average person of color lives in a census tract with hotter temperature indicators than census tracts with mostly white people in almost all 175 of the “largest urbanized areas” in the country.

The researchers found similar outcomes in people living below poverty.

Salas remembers an older adult patient who lived in a low-income Boston neighborhood. He was rushed to the emergency room, where doctors found he had a core temperature of 106 degrees, two degrees shy of the human limit to survive. He didn’t have an air conditioner.

“They only had one window that was open, during a Boston heat wave,” she said.

Natasha DeJarnett, an epidemiologist and professor of environmental medicine at University of Louisville's Christina Lee Brown Envirome Institute, specializes in air quality and cardiovascular disease risk. She said years of redlining are a major contribution to heat-related heart problems in people of color.

Redlining generally refers to a discriminatory practice, often in housing, that denies services to residents of certain areas based on race or ethnicity. In more than 100 U.S. cities, redlined communities had hotter summer surface temperatures than non-redlined neighborhoods, according to an analysis published in Climate.

“Formerly redlined communities are hotter and also have less tree cover,” she said. “Having more tree cover, more than just cooling the air... it’s also associated with cleaning the air.”

Trees are also known to improve cardiovascular health, DeJarnett explained, and reduce what scientists call the urban heat island effect, a metropolitan area that’s hotter than its surrounding area.

The COVID-19 pandemic is making matters worse

DeJarnett said access to cooling centers can be “life saving” and are a recommended intervention for preventing heat-related illness, especially for outdoor workers. But the pandemic has disrupted their use due to social distancing.

Dr. Joel Kaufman, a physician and epidemiologist who specializes in environmental health, has been leading a long-term national study on the relationship between air pollution and heart disease, called the Multi-Ethnic Study of Atherosclerosis and Air Pollution.

Kaufman and his colleagues found excess deaths related to air pollution appear to be linked to cardiovascular diseases, and that pollution is associated with progression of atherosclerosis. He also pointed to an association between heat events and heart disease.

More: Louisiana's communities of color already suffer from pollution and COVID. Now it's climate change.

“These heat events are associated with mortality – and most of that mortality ends up being cardiovascular morality,” Kaufman said. “Climate change and air pollution concentrations and their disparate effects on different populations are very related.”

Kaufman also noted disproportionate access to preventative health care increases risk of heat-induced heart problems, among a host of other health issues.

After her scare, Gabriel started going to a free clinic. But for many years, the Guatemalan immigrant didn’t have access to health care, she said.

She worries for her husband, who doesn’t have a doctor and has been suffering from severe headaches and other health concerns.

"I know it's a risk," she said about their work. But, "Who's going to pay our bills?"

“It’s getting hotter. Even when I started five years ago, it was less hot,” she continued. “I ask myself – what’s going to happen?”

Reach Nada Hassanein at or on Twitter @nhassanein_.