Warmer nights that are the result of climate change are putting more people at risk of stroke, researchers have said.
With climate change causing night-time temperatures to rise much faster than daytime temperatures, this latest study has found that extreme nocturnal heat – ‘tropical nights’ – increase the risk of stroke by 7%.
The German team behind the study say it is “extremely important” that changes are made to both urban planning and medical settings to reduce the risks posed by rising night-time temperatures.
Researchers highlighted how efforts must be made to reduce ‘urban heat islands’, which is when cities experience warmer temperatures than nearby rural areas. They also highlighted how staying informed about weather forecasts could help hospital chiefs be better prepared for more stroke patients that occur as a result of warmer nights.
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The findings could also help the general public protect themselves from the risk linked to hotter nights which are becoming more common, the team says.
The researchers examined data from 11,000 strokes over a period of 15 years and found that from 2006 to 2012, hot nights resulted in two extra strokes per year in the study area. From 2013 to 2020, there were 33 extra cases per year, which researchers called a “significant increase”.
The team, from Helmholtz Munich and the Augsburg University Hospital, found that elderly people and women are particularly at risk, and it is mainly strokes with mild symptoms that are diagnosed in medical clinics after hot nights.
‘Tropical nights’ are defined according to the ‘Hot Night Excess Index’ (HNE), which measure the extent to which temperatures rise above a specific threshold at night. This threshold is the temperature which is surpassed on the 5% warmest nights across the study period. In the case of this study, the threshold value was 14.6 °C.
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Research lead Dr Alexandra Schneider said: “We wanted to understand the extent to which high night-time temperatures pose a health risk. This is important because climate change is causing night-time temperatures to rise much faster than daytime temperatures.”
The study’s lead author, Dr Cheng He, said: “Our results make it clear that adjustments in urban planning and the healthcare system are extremely important to reduce the risks posed by rising night-time temperatures.”
Dr Schneider added: “The earlier these preventive measures are implemented, the better.”
Read the full study in European Heart Journal.
