A 15-year study has found a significant association between nocturnal heat exposure and increased stroke risk, emphasizing the importance of preventive measures to mitigate the potential impact of rising nighttime temperatures on cardiovascular health.

The study, published in the European Heart Journal, analyzed 11,037 stroke cases recorded between 2006-2020, focusing on the warm months of May to October. Using a time-stratified case-crossover approach, they discovered that exposure to extreme nighttime heat, as measured by the hot night excess (HNE) index, was associated with a 7% increase in stroke risk (odds ratio 1.07, 95% confidence interval 1.01–1.15).

Over time, the results revealed a significant increase in stroke risk associated with nocturnal heat exposure. Comparing the findings from 2013-2020 to those from 2006-2012, a 34% rise in HNE-related risk for all strokes and a 33% increase for ischemic strokes (P < .05) were observed.

The study also identified specific subpopulations that exhibited increased vulnerability to nighttime heat. Older individuals experienced a 37% increase in stroke risk, females a 31% increase, and patients with mild stroke symptoms (NIHSS score ≤ 4) a 48% increase during periods of extreme nocturnal heat.

Estimations showed that from 2006 to 2012, hot nights were attributed to an annual excess of two stroke cases. However, from 2013 to 2020, hot nights were associated with a total of 33 excess cases annually among the residents in the study area.

The importance of considering nocturnal heat exposure as a potential risk factor for stroke and the need for further research to develop targeted interventions and public health strategies were emphasized by the study's findings.

All authors declared no disclosure of interest for this contribution.