Rising Nighttime Temperatures Linked to Higher Stroke Risk

A new study investigates one way that the warming of our planet may adversely affect human health. The authors of the study found a 7% higher risk of strokes on warm nights, particularly among elderly women. 

The average temperature for both land and ocean surfaces between 2011 and 2020 signalled the warmest decade globally on record, surpassing the previous decade’s benchmark set in 2001 to 2010. The study’s authors suggest that as climate change progresses, it is becoming increasingly urgent to understand its ramifications on human well-being. 

Researchers found 11,037 strokes had been diagnosed between 2006 and 2020, from May to October, the months of greatest warmth. The average age of stroke patients was 71.3. The most common type of stroke recorded in the study was ischemic strokes, with 7,430 incidents. There were also 642 hemorrhagic strokes and 2,947 transient ischemic attacks. Most of the strokes included in the study were considered minor or moderate-severity strokes (85%). According to a study published in the European Heart Journal, transient ischemic attacks are temporary blood vessel blockages that mimic a stroke but do not lead to permanent symptoms. To analyze the association of these stores with hotter nights researchers used data from a local meteorological station that captured conditions by the hour which also includes temperature, relative humidity and barometric pressure. They also controlled daytime temperature to reduce its effects on nighttime stroke events. The researchers observed a slight increase in the number of hot-night strokes from 2013 to 2020 compared to 2006 to 2012, a period when temperatures were cooler. 

People who were most vulnerable to night heat were older, particularly women, and individuals with mild stroke symptoms. Some doctors who were not involved in the study said that the results were as expected since they analysed from past studies that extreme heat elevated temperatures increase cardiovascular events like heart attack and stroke. The cardiovascular system is a major part of human thermoregulation. When one has extreme heat, it interferes with how well the cardiovascular system can regulate the body temperature, and that puts the system under stress. Extreme heat is a stressor that can cause an increase in blood pressure and may even increase blood coagulability. Plus, those with pre-existing conditions may be particularly susceptible. 

Doctors suggest that the solution to this is to consume plenty of water before going to bed and have the windows open to allow circulation in one’s bedroom. Cool baths and showers, and cool clothes on the neck, forehead, and torso” can help lower body temperature.