Dr. Nguyen Huu Khanh, a neurologist at the neuroscience center at Ho Chi Minh City’s Tam Anh General Hospital, says the human body normally maintains a stable core temperature of around 37°C through its natural thermoregulation system.
When exposed to high outdoor temperatures, the body responds by sweating and dilating blood vessels to release heat.
But, if the body’s heat absorption exceeds its cooling capacity, the core temperature can rapidly rise above 40°C, affecting the central nervous system.
Workers at the construction site of the An Phu intersection construction in Thu Duc City, Ho Chi Minh City. Photo by Read |
High temperatures can disrupt the function of nerve cells and damage the blood-brain barrier, the protective layer that prevents harmful substances from entering the brain.
If this barrier is compromised, the brain becomes more vulnerable to swelling, inflammation, and oxygen deprivation.
In addition to the direct effects of heat, hot weather also causes loss of water and electrolytes through sweating. Reduced blood volumes make the blood thicker and slows circulation, creating conditions that favor clot formation. These can lead to blocked blood vessels in the brain, causing an ischemic stroke or worsening existing vascular diseases.
The brain is one of the body’s most oxygen-intensive and temperature-sensitive organs.
When the body temperature rises excessively, the brain’s metabolic demands increase while blood circulation declines due to dehydration. Prolonged oxygen deprivation can result in widespread death of nerve cells.
Areas involved in memory and motor control, such as the cerebellum and hippocampus, are particularly susceptible to damage from a heat stroke.
Extreme heat also triggers a systemic inflammatory response. Large amounts of inflammatory substances are released into the body, damaging blood vessels, increasing vascular permeability, and causing brain swelling.
Severe cases can cause coma, seizures, or multiple organ failure.
According to Dr. Khanh, neurological symptoms such as confusion, disorientation, weakness in the arms or legs, seizures, or loss of consciousness may indicate serious brain injury caused by prolonged overheating.
Heat stroke-related brain damage can leave lasting consequences, including memory impairment, reduced concentration, movement disorders, poor coordination, and changes in behavior or emotions.
Older adults and people with cardiovascular disease, hypertension, diabetes, obesity, or a history of stroke face a particularly high risk of neurological complications during heat waves.
Their ability to regulate body temperature is often diminished, while existing vascular damage increases the likelihood of reduced blood flow to the brain, blood clot formation, or stroke.
For this reason, Dr. Khanh recommends that high-risk individuals undergo regular health checkups and early screening for risk factors. Advanced imaging technologies such as 3-Tesla MRI and next-generation cerebral CT angiography can help detect narrowed blood vessels, aneurysms, and potential blockages at an early stage, reducing the risk of severe complications during extreme weather conditions.
He also advises people to limit outdoor activities between 10 a.m. and 4 p.m. on particularly hot days.
Staying hydrated and replenishing electrolytes is essential for those who work or exercise outdoors.
Anyone experiencing exhaustion, dizziness, or headaches after heat exposure should rest in a cool environment and lower their body temperature as soon as possible. If altered consciousness or other neurological symptoms develop, immediate medical attention is needed to prevent irreversible brain damage.
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