Heat Exposure May Triple US Cardiovascular Disease Burden by 2050

As global temperatures rise, the cardiovascular toll of extreme heat may be far greater than previously understood. A new study published in JAMA Cardiology projects that heat-attributable cardiovascular disease (CVD) burden in the US could nearly triple by 2050 under high-emissions climate scenarios and that the impact will fall disproportionately on aging and economically vulnerable populations.¹

Researchers from Case Western Reserve University analyzed county-level CVD burden data across all 3108 contiguous US counties from 2010 through 2016, then modeled future projections to 2030 and 2050 using 2 greenhouse gas (GHG) emissions pathways of a middle-of-the-road scenario (SSP 2-4.5) and a high-emissions scenario (SSP 5-8.5).

A Rapidly Escalating Burden

At baseline, heat-attributable CVD burden stood at 138.5 disability-adjusted life years (DALYs) per 100,000 population. Under the high-emissions scenario (SSP 5-8.5), that figure is projected to reach 418.2 DALYs per 100,000 by 2050, a more than 3-fold increase. Even under the more moderate SSP 2-4.5 pathway, projections show meaningful burden growth.

The study examined 3 components of DALYs: years of life lost (YLL), years lived with disability (YLD), and the composite DALY metric. Investigators found that rising temperatures alone drove substantial portions of the projected increase, but population aging added an additional 34% to the burden, independent of temperature changes, underscoring how demographic trends compound climate-related cardiovascular risk.

"Heat mitigation must become central to cardiovascular prevention, particularly for aging and economically vulnerable populations, with population aging increasing burden by 34%, independent of temperature,” wrote the study authors.

Disparities by Income and Geography

One of the study’s most striking findings is the unequal distribution of heat-attributable CVD burden across counties. Middle-income and low-income counties experienced higher relative burden increases compared with high-income counties, suggesting that economic disadvantage amplifies vulnerability to climate-driven cardiovascular harm.

These findings align with a growing body of evidence linking climate change to inequitable health outcomes. A systematic review presented at the American Heart Association Scientific Sessions (AHA) 2025 similarly found that older adults and patients with pre-existing cardiovascular disease were disproportionately affected by climate-related exposures and concluded that public health interventions, adaptation strategies, and mitigation policies are critical to reduce cardiovascular risks associated with a warming climate.²

Climate Change as a Cardiovascular Threat

The study adds to mounting concern that climate change could reverse decades of hard-won progress in CVD mortality reduction. Heat stress triggers a cascade of harmful physiological responses, including thermoregulatory strain, systemic inflammation, autonomic dysfunction, and a prothrombotic state, all of which increase cardiovascular risk. These mechanisms are particularly dangerous for older adults and those with pre-existing conditions such as hypertension, heart failure, or coronary artery disease.

The researchers used daily mean temperature recordings matched to county-level CVD estimates, allowing for a granular, geographically specific analysis that prior national-level studies have lacked. By linking these data to Intergovernmental Panel on Climate Change aligned GHG emissions pathways, the study provides a scalable framework for projecting regional CVD risk under different climate futures.

Implications for Policy and Practice

The findings carry significant implications for both health systems and policymakers. Cardiologists treating patients in lower-income or high-heat-exposure regions may need to consider environmental risk as part of routine cardiovascular risk assessment. At the policy level, the study makes a compelling case for integrating heat mitigation strategies, such as urban cooling infrastructure, cooling centers, and climate-resilient health system planning, into cardiovascular prevention frameworks.

With the US population aging and heat events intensifying, the authors argue that the window for effective intervention is narrowing. The study’s county-level granularity may also help health systems prioritize resources in communities where the projected CVD burden is greatest.

References

1. Parameswaran G, Ponnana SR, Sirasapalli SK, et al. Projected US cardiovascular disease burden from heat exposure for future greenhouse gas scenarios. JAMA Cardiol. Published online May 27, 2026. doi:10.1001/jamacardio.2026.1240
2. Prathiraja O, Elhassan KSE, Jain A, et al. Climate change and cardiovascular disease: a systematic review of environmental stressors and cardiovascular outcomes. Abstract presented at: AHA Scientific Sessions; November 7-10, 2025; New Orleans, LA.