Top Things to Know: Nonoptimal Temperature and Cardiovascular Health
Published: March 26, 2026
Prepared by Kate Hanneman, MD, MPH
- Both heat and cold exposure increase cardiovascular morbidity and mortality, including myocardial infarction, stroke, heart failure decompensation, arrhythmias, and sudden cardiac death. Climate change is intensifying these extreme temperature events, amplifying global cardiovascular risk.
- Short-term exposure to nonoptimal temperature can trigger cardiovascular events within days, with effects that may persist over subsequent weeks due to lagged physiological responses.
- The relationship between ambient temperature and cardiovascular risk is non-linear, with risk increasing at temperatures both above and below a location-specific optimal temperature. Optimal temperature thresholds vary substantially by geography, reflecting differences in climate, infrastructure, acclimatization, and social conditions.
- Vulnerability to nonoptimal temperature is not evenly distributed—older adults, people with cardiovascular disease, under-resourced populations, outdoor workers, and those without access to climate-controlled environments face disproportionately higher risk.
- Physiological mechanisms linking temperature extremes to cardiovascular events include autonomic and neurohormonal activation, endothelial dysfunction, inflammation, hemoconcentration, electrolyte imbalance, and impaired thermoregulation.
- Nonoptimal temperatures strain health care systems, increasing emergency visits, disrupting cardiovascular care delivery, challenging infrastructure, and affecting workforce capacity during extreme heat and cold events.
- Cardiovascular care itself contributes to health care-related greenhouse gas emissions, creating a paradox in which efforts to treat CVD may indirectly worsen climate-related cardiovascular risk.
- Preventive cardiovascular care is a climate adaptation strategy, as better control of hypertension, diabetes, and heart failure reduces vulnerability to temperature extremes.
- Mitigating temperature-related cardiovascular harm requires coordinated action across clinical care, public health, health systems, urban planning, and policy, alongside research to address knowledge gaps.
- Equitable interventions, such as access to cooling and warming centers, climate-resilient housing, and targeted risk communication, are essential to reducing temperature-related cardiovascular disparities.
Citation
Hanneman K, Alahmad B, Ghosh A, Khatana SAM, Huang M, Liu J, Abadi A, Khraishah H, Beckie T, Rajagopalan S, Angell S; on behalf of the American Heart Association Council on Cardiovascular Radiology and Intervention, Council on Epidemiology and Prevention, Council on Lifestyle and Cardiometabolic Health; Council on Cardiovascular and Stroke Nursing; Council on Clinical Cardiology; and Council on Lifelong Congenital Heart Disease and Heart Health in the Young. Nonoptimal temperature and cardiovascular health: a scientific statement from the American Heart Association. Circulation. Published online March 26, 2026. doi: 10.1161/CIR.0000000000001419