Climate Change and Cardiovascular Disease: Uncovering the Growing Threat to Public Health

BY KAI ELLIS

What if the air you breathe, the heat you feel, and the storms you endure were silently increasing your risk of heart disease? Climate change is no longer just an environmental issue—it’s a direct threat to human health, particularly cardiovascular health. Rising global temperatures, worsening air pollution, and more frequent extreme weather events have been linked to increased rates of hypertension, heart attacks, and strokes.¹ At the same time, disruptions to medical infrastructure, limited access to essential medications, and heightened psychological stress further compound these risks. As climate change continues to reshape public health, understanding its complex relationship with cardiovascular disease (CVD) is crucial. Recognizing these connections can help identify strategies to mitigate health impacts and protect vulnerable communities from the growing burden of CVD.²

While climate change poses cardiovascular health risks for all populations, its effects are felt more severely in certain communities, particularly those in rural areas. Research from the National Institutes of Health indicates that “the risk of heart failure was about 19% higher in rural residents than their urban counterparts.”³ One contributing factor is the limited availability of healthcare facilities in rural communities, making it more difficult for residents to receive timely medical intervention for cardiovascular conditions. Additionally, rural areas often have fewer resources to cope with extreme heat, a major environmental stressor linked to increased heart attacks and strokes. A study analyzing the accessibility of cooling centers for heat-vulnerable populations in New York State found that urban areas, on average, were only 2.93 miles from the nearest cooling center, whereas rural regions were an average of 11.63 miles away.⁴ This disparity highlights how rural communities are disproportionately under-resourced in preventative measures against climate-related health risks, further contributing to worsening CVD outcomes.

In addition to the unique challenges faced by rural communities, extreme weather events driven by climate change further exacerbate cardiovascular health risks on a broader scale. A recent study by JAMA Cardiology reviewed 492 observational studies and found that 245 of these events, which examined extreme temperatures and weather events like hurricanes, dust storms, and droughts, were strongly associated with increased morbidity and mortality from CVD. The investigators also observed that elevated ground-level ozone, which is amplified by higher temperatures, further increases the risk of CVD. For example, following Hurricane Sandy in 2012, which caused nearly $20 billion in damages and economic losses in New York City, data collected in the 12 months after the storm showed a significant increase in the risk of death from CVD, exemplifying how extreme weather events do not only cause immediate physical harm but also create long-term public health challenges.⁵ The study also revealed that individuals most affected by these climate-related health issues include older adults, racial and ethnic minorities, and people living in lower-income neighborhoods.⁶ These groups tend to experience more severe outcomes, including a higher incidence of CVD, as a result of pre-existing health disparities and lack of access to healthcare.

Extreme weather events are not the only climate-related factor endangering cardiovascular health—rising temperatures alone pose a significant and growing threat, particularly for older adults. Prolonged exposure to extreme heat increases the likelihood of hospital admissions due to CVD, as the body’s ability to regulate temperature declines with age. This reduced thermal regulation, particularly among those over 65, contributes to the increased risk of cardiovascular-related illnesses and deaths.⁷ Data from statistical studies—looking at hospital admissions, emergency department visits, and ambulance dispatches—also consistently show a positive correlation between extreme heat and the incidence of CVD. This evidence emphasizes the heightened risk that older adults face from climate-related heat stress and further emphasizes the urgent need for targeted public health strategies to mitigate the disproportionate risk for older more susceptible individuals.⁷

In addition to the direct physiological effects of extreme heat on older adults, climate change also impacts cardiovascular health through its influence on mental well-being. Climate change and extreme heat conditions can contribute to mental health issues such as anxiety and PTSD, which, in turn, may trigger or worsen (CVD). Additionally, heat exposure can impair cognitive function, which may affect a person’s ability to manage chronic diseases, further contributing to physical decline.⁸ Psychological stress caused by extreme heat can also put additional strain on the cardiovascular system, as it impacts the body’s ability to regulate internal temperatures. The resulting heat exhaustion and heatstroke can stress the heart and kidneys, further elevating blood pressure and worsening chronic health risks like CVD.⁹ This combination of psychological and physiological stress creates a dangerous feedback loop, increasing the overall burden on the body and worsening outcomes for individuals with preexisting health conditions.

Beyond its effects on mental health, climate change is also deteriorating the ground-level ozone layer, leading to increased air pollution, one of the most significant environmental risk factors for CVD. The Global Burden of Disease found that “nearly 45% of air pollution-associated deaths are due to CVD,” while only 8% are attributed to respiratory diseases.¹⁰ This stark contrast highlights the dominating impact of air pollution on public health and how it can increase the number of cardiovascular conditions and exacerbate existing cases.

A major contributor to air pollution’s harmful effects on cardiovascular health is particulate matter (PM), a mixture of tiny solid particles and gases that can be inhaled and infiltrate the body, triggering harmful cardiovascular responses. Once inside, PM contributes to CVD by inducing oxidative stress, where excess free radicals damage cells and tissues, and causing inflammation.¹¹ Exposure to increased concentrations of PM_2.5—particles with diameters of 2.5 micrometers or smaller, which are the most relevant to CVD—over a few hours to weeks can “trigger cardiovascular disease-related heart attacks and death.”¹² Long-term exposure to these particles has also been linked to the increased risk of mortality and decrease in life expectancy.¹² Exposure to PM and other environmental pollutants can enter the body through various pathways, ultimately leading to inflammation which can trigger increased blood clotting,¹³ activation of systems that regulate stress responses, metabolism, and the immune function,¹⁴ and damage to the autonomic nervous system.¹⁵ These disruptions lead to oxidative stress, small blood cells responding to signals of injury or inflammation, and increased arterial inflammation.¹⁶ Additionally, cellular signaling abnormalities emerge, which collectively result in blood clot formation on unstable plaques in arteries,¹⁷ altered glucose metabolism, development of hypertension,¹ and plaque instability. All of these increase the risk of adverse cardiovascular issues, such as heart attacks,¹⁸ irregular heart rhythms,¹⁹ and heart failure.

Building on the link between air pollution and cardiovascular risks, studies have shown that long-term exposure can lead to structural and functional changes in the heart and blood vessels. University of Washington’s decade-long Multi-Ethnic Study of Atherosclerosis Air Pollution Study stated that there is “a direct link between air pollution and atherosclerosis, which is a buildup of plaque in the coronary artery that can [negatively] affect heart health.”² In addition, a groundbreaking seminal article published in the medical journal The Lancet in 2016 by Dr. Joel Kaufman showed that long-term exposure to PM and nitrogen oxides, even at levels close to the National Ambient Air Quality Standards, can prematurely age blood vessels and accelerate the buildup of calcium in the coronary artery. This calcium can restrict blood flow to the heart and other major vessels, leading to a higher risk of cardiovascular events such as heart attacks and strokes.² 

Beyond its direct impact on cardiovascular health, climate change also poses challenges to medical treatment for CVD, as extreme temperatures can compromise the effectiveness and stability of essential medications. Certain medications, including insulin, anticoagulants (medicine to prevent blood clots²⁰), and blood products, are highly sensitive to heat and can degrade when exposed to high temperatures for prolonged periods. This issue is especially concerning in rural regions with limited access to reliable electricity or cold chain infrastructure, which is essential for maintaining the proper storage conditions of temperature-sensitive pharmaceuticals.²¹ Without adequate cooling systems, medications may lose potency or become unsafe for use, reducing their intended effectiveness and potentially leading to adverse health outcomes. For CVD patients, the degradation of essential medications can contribute to worsening conditions, increased hospitalizations, and higher mortality rates, highlighting the complex relationship between climate change and healthcare challenges.²²

The undeniable link between climate change and cardiovascular disease underscores the urgent need for action. Rising temperatures, worsening air pollution, and increasing extreme weather events are not just environmental crises—they are public health emergencies that disproportionately affect vulnerable communities. The knowledge that extreme heat amplifies CVD risks and that deteriorating air quality exacerbates heart disease should serve as a catalyst for change. By raising awareness and integrating climate-related health risks into medical practice, we can improve response times, enhance patient care, and promote more equitable healthcare solutions. Understanding these health impacts allows medical professionals to incorporate environmental factors into differential diagnoses, ensuring that patients receive comprehensive guidance on mitigating their risks.²³ However, the responsibility does not rest solely on the medical community. Policymakers, urban planners, and the public must work together to reduce emissions, strengthen healthcare infrastructure, and advocate for policies that protect both our planet and our health. Climate change is already reshaping public health, and without decisive action, its toll on cardiovascular well-being will only continue to grow.

Kai Ellis is a first-year in Berkeley College.

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