Extreme heat can profoundly impact the brain, affecting cognitive function, mood, and overall health. When exposed to high temperatures, the body works overtime to regulate its internal temperature, diverting blood flow to the skin to facilitate cooling. This shift in blood flow can lead to reduced blood supply to the brain, impairing its ability to function optimally. As a result, individuals may experience difficulties concentrating, processing information, and making decisions.
Heat stress can disrupt neurotransmitter activity in the brain, altering mood and behavior. High temperatures can exacerbate feelings of irritability, agitation, and even aggression. Heat-induced changes in serotonin levels, a neurotransmitter linked to mood regulation, may contribute to increased anxiety and depression during heatwaves where as Prolonged exposure to extreme heat can also impair memory and learning. Studies have shown that heat stress impairs synaptic plasticity, the brain’s ability to adapt and form new connections between neurons. This can hinder cognitive processes such as learning new information, retaining memories, and recalling information when needed.
Heat-related dehydration further compounds cognitive impairment. Dehydration reduces blood volume and can lead to decreased oxygen and nutrient delivery to the brain. Even mild dehydration can impair cognitive performance, affecting attention, motor coordination, and reaction time.
Additionally, heatstroke, the most severe form of heat-related illness, can cause direct damage to the brain. During heatstroke, the body’s core temperature rises to dangerous levels, leading to neurological dysfunction, seizures, and, in severe cases, coma or death. Heatstroke requires immediate medical attention to prevent permanent brain damage.
Few people are more vulnerable to the effects of extreme heat on the brain, including the elderly, children, individuals with preexisting medical conditions, and those engaging in strenuous physical activity outdoors. Poor access to air conditioning and inadequate hydration exacerbate these risks, particularly in regions experiencing heatwaves.
To mitigate the impacts of extreme heat on the brain, it is crucial to stay hydrated, seek shade or air-conditioned environments during peak temperatures, and avoid strenuous activities outdoors. Recognizing the signs of heat-related illness, such as confusion, dizziness, and nausea, is essential for prompt intervention and prevention of serious complications. Public health strategies, including heat wave warnings, urban planning for heat resilience, and community outreach programs, play a vital role in protecting vulnerable populations during periods of extreme heat.
The author is the Associate Director of Neurology, BLK Max Super Speciality Hospital.
