The risk of stroke is 7% higher when nighttime temperatures are very high, according to a new study which indicates that this phenomenon has worsened with global warming.
- Hot nights increase the risk of stroke by 7%, according to a new study, especially among women and the elderly.
- Between the period 2006-2012 and 2013-2020, rising temperatures increased the number of strokes per year.
- Hot nights led to two additional strokes per year between 2006 to 2012 and 33 between 2013 and 2020.
In 2023, during the four heatwave episodes, there were 1,500 deaths attributable to heat, which represents more than 10% of general mortality, according to Public health France. Among the causes is stroke, which, according to a new study published in the journal European Heart Journalwould strike more during warm nights.
7% increased risk of stroke during extreme heat at night
“We wanted to understand the impact of high nighttime temperatures in terms of health risks, explains Alexandra Schneiderone of the authors of the study. This is important because climate change is causing nighttime temperatures to rise much faster than daytime temperatures.“
For this, the team of researchers studied the data of around 11,000 patients who had a stroke during the hottest months, that is to say from May to October, between 2006 and 2020, in the region of Augsburg, Germany. Thus, scientists have observed that the risk of stroke is 7% higher at night when temperatures are high.
“Elderly people and women are particularly at risk, says Dr Cheng He, lead author of the study. These are mainly strokes with mild symptoms that are diagnosed (…) after hot nights.“
A rise in temperatures due to global warming
Global warming is implicated in these results. Indeed, researchers have observed an increase in the number of strokes as temperatures have increased over the past twenty years:
- Between 2006 to 2012:
– Hot nights led to 2 additional strokes per year.
– The average daily temperature during the hot season was 14.5°C.
– The daily maximum temperature was 19.6°C.
– There were 79 days of extreme nighttime heat.
- Between 2013 to 2020:
– Hot nights led to 33 additional strokes per year.
– The average daily temperature during the hot season was 14.8°C.
– The daily maximum temperature was 20.3°C.
– There were 82 days of extreme nighttime heat.
This study has several objectives. The first is to serve as a working basis to help public authorities and research to better take into account this risk, which will certainly increase in the future, in order to protect the population from heat and therefore from strokes.
Then, this work will also allow hospitals and emergency services to better anticipate and better prepare for the increase in people admitted for stroke during hot nights.