Alongside Semmelweis University, Budapest University of Technology and Economics, the University of Pannonia, and the National Ambulance Service, researchers analysed temperature data with over 116,000 out-of-hospital cardiac arrest cases over a five-year period.
The lowest risk for cardiac arrest was observed at 19°C, with the number of cases increasing as the temperature grew hotter or colder.
While there was notable risk above 27°C, the largest rise in risk was linked to cold spells (-9°C and below) lasting at least two days. This impact did not differ between men and women.
The researchers also identified an important difference in how heat and cold affect the body. Heat acts quickly and only up to a week, while cold spells place a longer-term strain on the body, with effects appearing after three days and increasing the risk of cardiac arrest for over two weeks after the cold period has ended.
“Although the effect of the weather is weak, it affects us all. In recent decades, climate change has made our weather more variable, and our bodies must adapt to this. This is particularly challenging for those who are unwell. While we have learned to pay attention to heatwaves, research shows that we must also consider the effects of cold weather,” Brigitta Szilágyi, Associate Professor at Corvinus University and co-author told That's Health.
The researchers offer practical implications; during heatwaves, healthcare services need to respond rapidly, while cold periods require heightened readiness over longer periods.
By incorporating these findings into regional warning systems, healthcare practices could also provide greater support, emphasising hydration during heat, and blood pressure management and appropriate clothing during cold periods.
These findings were first published in the journal Resuscitation Plus. The full paper is open access here
https://www.sciencedirect.com/science/article/pii/S2666520425003315?via%3Dihub
