Research thus highlights the specific risks of compound heat waves (that is to say during which heat is present during the day and continues during the night). This new modeling suggests that the previous ones could have underestimated the risk of more than 50 %.
These results call to adapt our health system and public health recommendations to climate change, notes one of the main authors, Dr Renjie Chen, of Fudan University: “Combined heat waves have a significantly higher risk for heart health than only diurnal or only nocturnal heat”.
Previous research has established a link between short -term exposure to heat waves and an increase in mortality by heart disease The effects of different models of heat waves remain poorly understood.
-When the night does not refresh more
The study Analysis of data of nearly 2.4 million deaths by heart disease in continental China over a period of 6 years and compares the deaths of diurnal, night and day-free heat waves. The team uses a new measure of the impact of heat waves, called excessive cumulative temperatures during heat waves (excess cumulative temperatures in heatwaves or ect-hw). This new metric makes it possible to capture all the characteristics of heat waves, including their intensity, duration and chronology during the season. This analysis notes that:
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the mortality rate associated with Holled heat waves Gradually increases with exposure;
- These waves of daytime heat and nocturnal Non-linear trends follow effects that appear that appear only beyond specific thresholds;
- The risk is not the same for the different types of heart disease;
- Sudden cardiac arrest, myocardial infarction and heart failure prove to be particularly sensitive to combined heat waves, while pulmonary heart diseases cause this high risk of death in the event of exposure to high intensities.
Clinical and public health implications: While the different types of heat waves affect the incidence and consequences of heart disease differently, prevention measures must take into account the type and intensity of heat waves. Given their greater impact, combined heat waves must be explicitly taken into account in risk assessment and in the implementation of early alert systems.
The team then provides additional research, in particular to predict cardiac mortality models linked to heat waves according to different climate change scenarios.
