Extreme heat drives up stroke risk in Vietnam

At Nhan Dan 115 Hospital in Ho Chi Minh City, the Cerebrovascular Disease Department is treating around 200 stroke patients, most aged between 50 and 70.

Notably, an increasing number of cases are being recorded among younger people, including those in their early 30s, doctors said.

Dr. Nguyen Huy Thang, head of the department, warned that hot and humid conditions can significantly increase stroke risk.

He explained that high temperatures accelerate dehydration, thickening the blood and increasing the likelihood of blood clot formation, thereby contributing to an increased risk of stroke.

The risk of stroke rises further with prolonged exposure to direct sunlight or when body temperature exceeds 40 degrees Celsius.

Cold weather can also have similar effects, as people tend to drink less water and become dehydrated, Thang added.

He underscored that in both hot and cold weather, sudden temperature fluctuations can disrupt normal blood vessel function, raise blood pressure and place additional strain on the heart, which may further elevate stroke risk.

This is particularly dangerous for older adults and people with underlying conditions such as poorly controlled hypertension.

Recent international studies have reinforced the link between weather conditions and stroke risk.

A study presented at the 2022 European Society of Cardiology Congress in Japan, involving 3,367 people aged 65 and older in Okayama city, found that stroke risk rose significantly about one month after the rainy season.

For every one-degree Celsius increase in temperature, the risk of hemorrhagic stroke rose by 24 percent, while the risk of ischemic stroke increased by 36 percent.

Another study across eight major Chinese cities, covering a population of 48 million, found that both extreme heat, between 28 and 34 degrees Celsius, and cold temperatures, from four to 23 degrees Celsius, were associated with higher stroke risk.

The impact of heat typically appeared within the first three days of exposure, while the effects of cold weather could persist for up to two weeks.

According to Thang, periods of seasonal transition, when temperatures fluctuate sharply, pose the highest risk.

He added that the body may gradually adapt over time, reducing the impact.

Vietnam has yet to conduct large-scale studies on the relationship between weather and stroke, but clinical observations suggest the link is well established.

Experts say weather should be considered a contributing factor rather than a direct cause of stroke, except in cases of severe hyperthermia.

To reduce risk during hot weather, doctors advise limiting direct exposure to sunlight, especially during peak hours, avoiding excessive physical exertion in high temperatures, and maintaining adequate hydration.

Controlling underlying conditions, particularly hypertension, is essential, as blood pressure can spike under extreme weather conditions.

Older adults, people with obesity, and those with multiple underlying health issues are considered high-risk groups and should be closely monitored.

Using fans or air conditioning can help regulate body temperature.

In suspected cases of heat-related stroke, immediate cooling measures such as cool baths, ice packs or air conditioning should be applied, while the patient is promptly taken to the nearest medical facility for emergency care.

According to the National Center for Hydro-Meteorological Forecasting, severe heat has affected much of the country in recent days, with temperatures peaking at 41.9 degrees Celsius on April 7 in north-central Nghe An Province.