Effects of Climate Change on the Human Nervous System

Doctors warn that the problems faced today by people with neurological disorders could, in the future, also affect healthy individuals due to global warming.

A hotter planet—especially through extreme heat waves—is not only a threat to ecosystems or infrastructure, but also has profound effects on the human brain. Rising heat disrupts brain function and exacerbates neurological diseases. During Europe’s 2003 heatwave, about 7% of excess deaths were directly linked to neurological problems.

Dr. Sanjay Sisodiya, a neurologist at University College London and a pioneer in studying the link between climate change and brain function, has found that heat can worsen conditions such as epilepsy, stroke, migraine, encephalitis, multiple sclerosis, and even mood disorders and aggression.

The brain requires precise regulation of body temperature to maintain its own stable temperature. This regulation occurs through blood flow and a network of neural mechanisms, which can malfunction under extreme heat. Such disruptions can be more severe in people with pre-existing neurological conditions—especially if they take medications that impair sweating or temperature regulation.

Rising nighttime temperatures also disturb sleep, increasing the risk of seizures, depression, or neurological exhaustion. Patients with dementia, particularly the elderly, face a higher risk of hospitalization or death during hot days, as they have reduced physical capacity and weaker memory to cope with heat.

Evidence also suggests that extreme heat increases premature births, which can delay the neurological development of newborns. Heat may also weaken the blood–brain barrier, making it easier for viruses and toxins to enter brain tissue. The spread of mosquitoes such as Aedes—which transmit viruses like Zika and dengue—due to higher temperatures further amplifies this risk.

Doctors caution that the neurological issues we see today in vulnerable patients may, in the future, affect healthy people as well, because some individuals are genetically more susceptible to heat. Climate change could reveal these hidden vulnerabilities.

Experts stress the need for better identification of vulnerability patterns to protect at-risk groups, as well as solutions such as early-warning systems and economic support for day laborers. As the UN Secretary-General warns that we have entered an era of “global boiling,” the human brain stands on the frontline of climate-related threats.