Climate Change Impacts: Rising Temperatures Linked to Increase in Stroke Deaths

In 2019, over 500,000 people died from strokes caused by extreme temperatures, according to a recent study. As the planet continues to warm due to human activities, this number is projected to increase.

A study published in the medical journal Neurology on Wednesday revealed that since 1990, the incidence of strokes related to high and low temperatures has been on the rise worldwide. Although men experienced more temperature-related strokes than women, individuals of all ages were affected.

TOPSHOT - A woman walks along The Embarcadero under an orange smoke-filled sky in San Francisco, California on September 9, 2020. - More than 300,000 acres are burning across the northwestern state including 35 major wildfires, with at least five towns "substantially destroyed" and mass evacuations taking place. (Photo by Brittany Hosea-Small / AFP) (Photo by BRITTANY HOSEA-SMALL/AFP via Getty Images)

A woman is seen walking along The Embarcadero in San Francisco, California, under a sky filled with orange smoke on September 9, 2020. The state is currently dealing with over 300,000 acres burning in wildfires, with 35 major fires causing significant damage. At least five towns have been reported as "substantially destroyed," leading to mass evacuations in the affected areas.

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Researchers from Xiangya Hospital Central South University in China conducted a study on the relationship between temperatures and strokes in 204 countries and territories. They developed a model using global data on disease, deaths, disability, and climate factors such as temperatures, cloud cover, and weather variables. This study aims to train a new generation of 'climate doctors' who can understand and address the impact of climate on health.

The study authors found that the increasing number of strokes is not solely due to the aging population. They pointed out that "nonoptimal temperatures" played a significant role in the rise of stroke cases. In 2019, more people suffered strokes due to both hot and cold temperatures compared to 1990.

Surprisingly, in 2019, it was the cold temperatures that were linked to a higher number of strokes. This may seem contradictory in the context of global warming, but cold temperatures are also a result of climate change. The warmer temperatures on land disrupt the polar vortex, which is a cold air mass around the poles. When this vortex weakens, it can lead to cooler temperatures and potentially increase the risk of strokes.

Currently, stroke fatalities linked to extreme temperatures are more prevalent in regions with higher poverty levels and weaker healthcare systems, such as Africa. According to the study, the significant rise in stroke cases caused by hot weather in Central Asia also needs to be addressed.

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According to a study, as the Earth heats up, the number of strokes caused by high temperatures has been rising quickly. This trend is expected to continue increasing significantly in the future.

Higher temperatures are already here, with last year being the warmest since scientists began recording global temperatures in 1850. It is expected that temperatures will continue to break records in the near future. In fact, this March was the hottest one on record.

Dr. Mary Rice, an associate professor of medicine at Harvard Medical School, emphasized the significance of the findings in the new study, even though she was not directly involved in the research.

Rice, a pulmonologist at Beth Israel Deaconess Medical Center in Boston, praised the group for their global approach in analyzing historical data to bring attention to a lesser-known health issue. He emphasized the significant impact of temperature-related strokes on global mortality rates.

In a recent study published in Frontiers in Science, Rice highlighted the link between climate change and the rise of immune-mediated diseases like allergies, asthma, autoimmune disorders, and cancers. The study underscores the urgent need for comprehensive efforts to reduce emissions, improve air quality, and tackle the challenges posed by climate change.

Without immediate global action, the world is going to see a much greater burden of disease, she said.

‘It’s happening across the board’

Stroke is already a significant health problem. It is the third leading cause of disability worldwide, and one of the leading causes of death, earlier studies showed.

AUSTIN, TEXAS - AUGUST 08: An Austin-Travis County medic assists a patient in an ambulance on August 08, 2023 in Austin, Texas. EMT were called after the patient was found passed out and dehydrated near the Texas State Capitol. The city of Austin continues grappling with a prolonged heat wave, with excessive heat-advisories being issued across the state. (Photo by Brandon Bell/Getty Images)

An Austin-Travis County medic helped a patient in an ambulance in Austin, Texas. The patient had passed out and was dehydrated near the Texas State Capitol, prompting a call for EMT assistance. The city of Austin is facing a prolonged heat wave, leading to excessive heat advisories being issued throughout the state.

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The new study did not aim to explain why extreme temperatures associated with the climate crisis are linked to an increased risk of strokes. However, previous research has indicated that in very hot weather, the body struggles to regulate its temperature through sweating. This can result in a higher likelihood of blood clotting, known as a hypercoagulable state, which raises the risk of strokes. Dehydration is another factor that can put strain on the heart, further increasing the chances of experiencing a stroke or heart attack.

On the other hand, extreme cold temperatures can also contribute to the risk of strokes. Exposure to cold triggers the skin's cold receptors, activating the sympathetic nervous system responsible for the body's fight or flight response. This can lead to vasoconstriction, the narrowing of blood vessels in the skin, arms, and legs, causing a spike in blood pressure and potentially leading to a stroke.

Dr. Ali Saad, a neurologist from the University of Colorado's Climate and Health Program, discusses the dangers of extreme temperatures with stroke patients. He emphasizes the risks, especially from heat, and helps patients stay informed by setting up weather alerts on their phones.

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Saad expressed his concerns to them, saying, "I'm worried that you may overheat, but there are actions we can take to prevent strokes and help combat climate change."

Saad did not participate in the new study, but he expressed his hope that this latest research will catch the attention of global leaders and impact public policy.

According to Saad, the study sheds light on the fact that extreme temperatures are a risk factor for stroke, which is already known. However, what sets this study apart is that it is the first to explore this issue on a global scale. Saad mentioned that when people think of pollution or heat affecting health, they usually associate it with low- to middle-income countries. He emphasized that these issues are prevalent worldwide and are expected to worsen in the future.

Editor's P/S:

The article presents a sobering picture of the increasing incidence of strokes due to extreme temperatures, a consequence of the planet's warming climate. The study's findings highlight the urgent need to address the climate crisis, as it poses significant health risks beyond those traditionally associated with air pollution and heat. The rise in strokes due to cold temperatures is particularly concerning, demonstrating the complex and varied effects of climate change on human health.

It is alarming that strokes, already a major health concern, are now being exacerbated by extreme temperatures. The study's global scope underscores the universality of this issue, affecting both developed and developing countries. It is essential to raise awareness about the link between climate change and strokes, as well as the need for preventive measures. Governments, healthcare professionals, and individuals must work together to mitigate the risks and protect public health from the growing threat of climate-related strokes.