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Healthcare
May 29, 2024

Study Finds Hot Nights and Extreme Temperatures Could Heighten Risk of Stroke

A study indicates that elevated temperatures during hot nights and extreme weather conditions could amplify the risk of stroke. This finding underscores the potential health consequences linked to temperature fluctuations, urging further investigation and awareness of environmental factors in stroke prevention strategies.

A research inquiry investigates the correlation between elevated temperatures during nighttime and the likelihood of experiencing a stroke. (Image Credit: Jose Gonzalez Buenaposada/Getty Images)
  • In a recent study, older individuals, particularly women, were discovered to have a higher likelihood of experiencing a stroke during hot nights.
  • Elevated temperatures can interfere with the cardiovascular system's operation, serving as a significant stressor and influencing the contraction and dilation of blood vessels.
  • To mitigate the risk of stroke during hot nights, it is recommended to stay hydrated, maintain airflow, take cool showers or baths, and wear cool clothing on the forehead and torso.
  • The research highlights nocturnal heat as a crucial factor triggering stroke incidents in a progressively warming climate.

A recent research endeavor explores a potential pathway through which the Earth's rising temperatures could detrimentally impact human health.

According to the study's authors, there was a 7% increased likelihood of strokes occurring during warm nights, with elderly women being particularly vulnerable.

Data from 2011 to 2020 indicates that the average temperature across land and ocean surfaces marked the warmest decade globally, surpassing the previous decade's record set between 2001 and 2010.

The authors of the study propose that as climate change advances, it becomes progressively crucial to comprehend its implications for human health and welfare.

Hot temperatures linked to higher stroke risk

Researchers conducted a new study using patient records from Augsburg Hospital in Germany spanning 15 years. They identified 11,037 cases of stroke diagnosed between 2006 and 2020, predominantly occurring from May to October, the warmer months, with an average patient age of 71.3 years.

Ischemic strokes were the most frequent type recorded, comprising 7,430 cases, followed by 642 hemorrhagic strokes and 2,947 transient ischemic attacks. The majority of strokes were classified as minor or moderate in severity (85%).

Ischemic strokes result from blood vessel blockage, while hemorrhagic strokes occur due to vessel rupture or tearing. Transient ischemic attacks, termed "warning strokes," are temporary blockages mimicking stroke symptoms without causing permanent damage.

To gauge the relationship between strokes and warmer nights, researchers analyzed meteorological data from a local station capturing hourly temperature, humidity, and barometric pressure. They adjusted for daytime temperatures to minimize their influence on nocturnal stroke occurrences.

Comparing 2013-2020 to 2006-2012, a period of cooler temperatures, researchers noted a slight uptick in stroke incidents during warm nights.

Elderly individuals, particularly women, and those experiencing mild stroke symptoms were most susceptible to the effects of nighttime heat.

”Concerning, not surprising” study results

"The findings are concerning, albeit not unexpected," remarked Dr. Cheng-Han Chen, a cardiologist at Saddleback Medical Center in California, who was not involved in the research. "Previous studies have already indicated that elevated temperatures, particularly during extreme heat, heighten the risk of cardiovascular events like heart attacks and strokes." He highlighted the study's robust statistical analysis spanning several years, emphasizing the apparent significance of the observed trend.

Dr. Jayne Morgan, a cardiologist and Executive Director of Health and Community Education at Piedmont Healthcare Corporation in Atlanta, Georgia, approached the study's conclusions with more caution. Although acknowledging the established link between extremely hot weather and increased heart attack risk, she pointed out the absence of definitive causality regarding strokes.

Furthermore, Morgan expressed reservations about the study's homogeneous participant pool, questioning the applicability of its findings to a more diverse global population. She also raised concerns about the average age of 70 among the study participants, suggesting that age-related factors might confound the association between strokes and heat.

Moreover, Morgan highlighted the lack of sub-analyses and the significant proportion of participants with unspecified gender in the study, underscoring potential limitations in drawing firm conclusions from the research.

Why heat may increase risk of stroke

Chen elaborated, stating, "The cardiovascular system plays a crucial role in regulating body temperature. When faced with extreme heat, this regulatory function is compromised, placing significant stress on the system."

Morgan highlighted, "Heat-induced dehydration strains both the heart and the body, while excessive sweating can disrupt electrolyte balance."

Chen added, "Heat alters the constriction and dilation of blood vessels, potentially triggering cardiovascular events such as heart attacks and strokes."

Consequently, Morgan emphasized, "Extreme heat acts as a stressor, elevating blood pressure and potentially increasing blood coagulation. Individuals with pre-existing conditions may be particularly vulnerable to these effects."

How to safeguard against stroke in hot weather

Both Chen and Morgan underscored the importance of maintaining adequate hydration, particularly during hot nights and days.

"Ensure you drink plenty of water before bedtime," advised Chen. He also recommended maximizing airflow in the bedroom by keeping windows open to facilitate the evaporation of sweat, aiding in body cooling.

Morgan recommended cooling baths, showers, and placing cool cloths on specific areas like the neck, forehead, and torso to help lower body temperature.

Expressing concerns about the broader implications of climate change on cardiovascular health, Morgan highlighted the potential adverse effects of pollution and increased particulate matter. These pollutants, she cautioned, can infiltrate the lungs and bloodstream, posing risks to healthy heart tissue.

What are the different types of stroke?

The two primary categories of stroke are ischemic and hemorrhagic. Ischemic strokes arise from blockages in blood vessels, while hemorrhagic strokes occur due to bleeding in or around the brain.

A stroke occurs when there's a sudden interruption to the blood and oxygen supply to a portion of the brain. Ischemic strokes, which are the most common, happen when a blockage impedes adequate blood flow to brain cells.

Hemorrhagic strokes, constituting 10–20% of all strokes, encompass two types: subarachnoid hemorrhages, involving bleeding around the brain, and intracerebral brain hemorrhages, involving bleeding within the brain tissue.

Transient ischemic attacks (TIAs), or ministrokes, are brief episodes lasting only a few minutes but can serve as precursors to major strokes.

This article delves into the various stroke types, their causes, symptoms, and potential treatment modalities.

Ischemic stroke 

A person may have a stroke when there is a sudden disruption to the blood and oxygen supply to the brain.

Ischemic stroke is the most prevalent type, occurring when a blood vessel clot obstructs proper blood flow to the brain, often associated with conditions like atherosclerosis. Clots originating from the heart or carotid arteries can also trigger ischemic strokes.

Symptoms include sudden numbness, weakness on one side of the body, facial drooping, vision changes, dizziness, confusion, and severe headache without a known cause.

Risk factors include high blood pressure, cholesterol, untreated diabetes, atherosclerosis, smoking, excessive alcohol intake, limited exercise, age over 65, atrial fibrillation (A-fib), and vasculitis.

Urgent treatment focuses on clot removal and preventing further brain damage. Tissue plasminogen activator (TPA) or alteplase is typically administered intravenously to dissolve clots swiftly. Thrombectomy, a surgical procedure to remove clots, may be necessary within 6 hours of symptom onset, potentially up to 24 hours.

Post-stroke care involves managing fluids, blood pressure, glucose, and inflammation. Blood thinners like heparin may be prescribed if TPA or surgical intervention is no longer feasible.

Recovery often entails speech, occupational, physical, and psychological therapies, alongside lifestyle modifications to minimize stroke recurrence, such as dietary changes and increased physical activity.

Hemorrhagic stroke 

Hemorrhagic stroke occurs when a blood vessel ruptures or leaks, leading to bleeding within the brain. The accumulated blood compresses nearby brain tissue, causing rapid tissue death.

Symptoms resemble those of ischemic stroke, including numbness, loss of function (especially on one side of the body), facial drooping, speech difficulties, loss of consciousness, confusion, severe headache, and seizures.

Possible causes include aneurysms and arteriovenous malformations (AVMs). Aneurysms, enlarged blood vessels prone to rupture, can be congenital, hereditary, or result from factors like high blood pressure, smoking, alcohol use, drug use (e.g., cocaine), and head trauma. AVMs, abnormal blood vessel structures present from birth, can also rupture, causing hemorrhagic stroke.

Treatment may involve surgical removal of blood and repair of the vessel. Alternatively, management focuses on fluid control and monitoring for complications like seizures. Medications to regulate blood pressure may be administered to mitigate brain damage.

Transient ischemic attack 

A transient ischemic attack (TIA), also known as a ministroke, shares similarities with an ischemic stroke as it momentarily obstructs blood flow to the brain. However, TIAs are temporary and resolve on their own as the clot either shifts or dissolves. Treatment focuses on preventing future occurrences, as individuals who experience a TIA have an elevated risk of a major stroke later on.

Symptoms of a TIA can mimic those of an ischemic stroke but are typically milder and last only a few minutes. These may include confusion, difficulty walking, facial drooping, tingling, or numbness.

Risk factors for TIAs mirror those for ischemic strokes and encompass aging, smoking, sedentary lifestyle, cardiovascular disease, and atrial fibrillation (A-fib). Approximately 15% of strokes are preceded by TIAs, indicating a significant predictive value for future stroke occurrence.

Preventive measures for individuals who have experienced a TIA involve consulting with a healthcare professional regarding lifestyle modifications, medications, and other interventions aimed at reducing the likelihood of subsequent ischemic strokes.

Other types of stroke

When a healthcare provider is unable to ascertain the cause of disrupted blood flow to the brain, it's termed a "cryptogenic" stroke. This diagnosis is made when extensive tests fail to reveal any identifiable stroke risk factors. Symptoms of a cryptogenic stroke resemble those of other strokes, but treatment can be challenging due to the absence of a clear underlying cause.

To address this, doctors may conduct a range of diagnostic tests and recommend lifestyle changes to mitigate the risk of recurrent strokes.

A brain stem stroke, while not a distinct stroke type, occurs within the brain stem, either as ischemic or hemorrhagic. It can present with complex symptoms and pose diagnostic challenges.

Common symptoms include dizziness, confusion, numbness, and difficulty walking. Unlike most strokes, brain stem strokes may manifest symptoms on both sides of the body and can even lead to paralysis in some instances.

Treatment for brain stem strokes mirrors that for other stroke types, focusing on clot removal or hemorrhage control, depending on the underlying cause. Since brain stem strokes can affect breathing, emergency respiratory support may also be necessary.

Summary

Healthcare professionals advocate using the acronym "FAST" to promptly identify and intervene when someone is experiencing a stroke:

F: Face drooping A: Arm weakness S: Speech difficulties T: Time to seek emergency medical attention

Stroke is a medical emergency, and immediate treatment is crucial.

Source: medicalnewstoday

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