Heat waves and cold waves increase risk of heart attacks and other cardiovascular issues
A study of more than 8 million people found that heat waves trigger immediate increases in cardiovascular events, while cold waves produce delayed effects over several days. The analysis, covering 2011 to 2020, recorded significant increases in cardiovascular deaths and major adverse events under both temperature extremes.
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Heat waves and cold waves increased the risk of major adverse cardiovascular and cerebrovascular events (MACCE) in Eastern Poland over the 2011–2020 study period, based on geospatial analysis of over 8 million residents.
The dataset included 573 538 MACCE events, 377 373 cardiovascular deaths, and 831 246 all-cause deaths recorded through the National Health Fund.
Heat wave exposure produced an immediate response. On the day of a heat wave, MACCE increased by 7.5%, while cardiovascular deaths rose by 9.5%. These increases were recorded on the same day as exposure.
Cold wave exposure followed a delayed temporal pattern. MACCE increased between 4.0% and 5.9%, while cardiovascular deaths increased between 4.7% and 6.9% over several days after exposure.
Exposure to air pollution was associated with additional increases in cardiovascular risk during both temperature extremes. During heat waves, ozone (O3) and benzo[a]pyrene were linked to higher event rates. During cold waves, ozone, fine particulate matter (PM2.5), and nitrogen dioxide (NO2) were associated with increased risk.
Stronger effects were observed among women and younger individuals within the studied population.
The study was presented at ESC Preventive Cardiology 2026 and conducted by researchers from the Medical University of Białystok.
Temperature extremes were indexed using the Excess Heat/Cold Factor, and outcomes were defined using a composite endpoint including cardiovascular death, ST-segment elevation myocardial infarction, and ischemic stroke.
Temperate climates remain understudied in relation to temperature-related cardiovascular impacts. The dataset captures conditions in a region experiencing both heat waves and cold waves, allowing direct comparison of immediate and delayed cardiovascular responses under different temperature extremes.
References:
1 Heatwaves and coldwaves are increasing cardiovascular events – European Society of Cardiology – April 24, 2026
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
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