How Weather and Air Pollution Affect Heart Health

When temperatures climb, the cardiovascular system works harder to keep the body cool by redirecting blood flow from the core to the surface of the skin to allow for evaporation. High temperatures can cause blood to coagulate and thicken, which makes the process even harder on the heart. During heat waves, deaths related to cardiovascular disease can increase by 12–17%.

“A big risk of heat waves is not just the heat itself, but the independent risk for heart attacks and strokes,” says Andrew Chang, MD, PhD, assistant professor of medicine (cardiovascular medicine). “As extreme temperatures become more common, it’s important for the medical community to help people understand the risks – and how to prevent any complications.”

It’s not just high temperatures that can put stress on the heart. Other environmental factors, such as air pollution, extreme cold, hurricanes, wildfires, and other climate events, can contribute to or worsen cardiovascular conditions.

“The environment affects everyone, from the sickest of the sick to healthy individuals. Over time, the cumulative impacts of stress on a healthy heart can cause real damage,” says Lavanya Bellumkonda, MD, associate professor of medicine (cardiovascular medicine). “There’s so much we can do to prevent this environmental stress on the cardiovascular system.”

Each year, air pollution contributes to more than eight million deaths worldwide. Although some of these deaths are attributed to pulmonary causes, like asthma and COPD, nearly 70% of the deaths are from cardiovascular causes. Research has shown that even an hour of exposure to high levels of particulate matter causes an increase in heart attack and stroke rates.

Bellumkonda recently co-authored a review article in Circulation: Heart Failure that detailed the effects of air pollution on people with heart failure and presented a clinical framework for assessing and managing air pollution exposure in this patient population.

“We’ve learned that people with heart failure who are exposed to higher levels of air pollution have worse outcomes than people with less exposure to pollutants,” says Bellumkonda. “We need to think of air pollution as a modifiable risk factor, just like diet and exercise.”

Even for those without heart failure or other forms of cardiovascular disease, air pollution contributes to the long-term, cumulative development of cardiovascular risk factors.

Chang recently published research using cardiac ultrasound strain imaging to identify heart muscle dysfunction in otherwise healthy older adults, finding that even small increases in annual exposure to air pollution affected heart function. “Even if you don’t see it on the surface, the heart is already affected,” Chang says.

Bellumkonda and Chang are working to educate clinicians about the relationship between the environment and heart health so they can better help their patients alleviate some of the complications from environmental stress.

At the bedside, clinicians can assess their patients’ environmental risk by asking questions about where they work, how close they live to highways, if they exercise outdoors, and how they commute to work, says Bellumkonda. Once clinicians understand each patient’s risk, they can share tangible steps to reduce environmental harm.

“In general, Americans are aware that the environment can harm their health. The problem is that no one thinks they will personally be affected,” Chang adds. “Part of our job is to explain to our patients that they are part of a vulnerable population and must take precautions, like visiting a cooling center and staying hydrated on hot days or using air filters or N95 masks when the air quality is poor.”

“We are experiencing more and more major environmental events, so as a medical community, we need to think about how to plan for these events and protect people,” says Bellumkonda. “It’s not just the heart patients in front of us, who are already sick. We also need to think about those who are healthy and prevent them from developing heart disease.”

Cardiovascular Medicine, one of 10 sections in the Yale Department of Internal Medicine, is dedicated to improving cardiovascular health by advancing groundbreaking research, training the next generation of experts in cardiology, and delivering world-class patient care to people with a range of cardiovascular issues. To learn more, visit Cardiovascular Medicine.