As the world continues to warm, conditions such as dementia, epilepsy and depression may spread and worsen in severity. In a study released Wednesday, researchers at University College London analyzed the neuroscience literature to explore how extreme heat and climate change-induced disasters affect major neurological diseases and mental health disorders. They found that environmental factors not only influence disease prevalence but can also increase the associated risk of hospitalization, disability, and even death.
The effects of climate change on health have been well studied, especially when it comes to infectious and respiratory diseases. But it also impacts neurological health, with the body’s temperature regulation process appearing to be a major driver in the exacerbation of conditions resulting from extreme heat.
“To function properly, the brain needs to be maintained within a relatively narrow temperature range,” said Professor Sanjay Sisodia of the UCL Queen Square Institute of Neurology, who led the research. “If there is any disease in the brain, the brain’s ability to thermoregulate becomes compromised. Take someone with a neurological disease and expose them to an extraordinary heat wave, you can see how it can make their neurological disease worse.
The exact mechanisms linking high temperatures to neurological disorders require more investigation, Sisodia said. As extreme weather worsens and becomes more common, it becomes increasingly important to unravel the exact relationship, especially for the youngest, oldest and most vulnerable populations.
For the new study, researchers reviewed 332 reports looking at environmental effects on 19 neurological conditions with the highest disease burden, including Alzheimer’s and other types of dementia, migraine, stroke, multiple sclerosis and meningitis. He also collected research on depression, anxiety, and schizophrenia because psychiatric disorders often have co-morbidity with neurological diseases. The findings show that weather affects each disease in different ways, but most conditions are broadly associated with higher prevalence and worse symptoms.
Among their findings are that people with Alzheimer’s and other dementias struggle to make adaptive choices such as seeking help in extreme heat, wearing light clothing and drinking more water. Hot weather is also more likely to cause fatal or disabling strokes and can affect epilepsy, which is made worse by lack of sleep. Higher nighttime temperatures are a hallmark of climate change and may affect sleep patterns. (Research also found that extreme cold can also affect health.)
The risk of hospitalization and death, as well as the incidence of mental health disorders, were most strongly associated with increases in ambient temperature. A new study surveyed reports that U.S. health insurance claims for mental health-related emergency room visits increased on days of extreme heat between 2010 and 2019. Extreme weather events like hurricanes and wildfires can trigger severe cases of anxiety, post-traumatic stress, depression and suicidal ideation.
Bursin Ikiz, a neuroscientist who studies the impact of environmental patterns on the brain, said the brain’s response to a hot climate causes damage that may not be detected until medical intervention becomes effective. When the heat rises, he said, “our brains go into stress response” which can lead to inflammation and other types of decline that affect cognitive health.
“The thing that scares me most about this scenario is that by 2050, we will not only see an explosion of people with neurological disorders, but it will be in our 40s and 50s rather than our 70s and 80s because our “The brain is impacted by various stressors such as heat, pollution and microplastics,” said Ikeys, founder and chair of the International NeuroClimate Working Group, an effort to promote more research and advocacy about the threat of climate change to the brain. It is an initiative.
Sisodia and Ikis called for more research and policy interventions to reduce the economic impact of climate change on individuals and public health systems, especially in poor countries. As the world faces another round of record-breaking heat, however, there are steps people can take to protect against extreme heat.
“We have to stop burning fossil fuels, stop putting emissions into the air,” Sisodia said. “But in addition, we can ensure that weather alerts are appropriate, informative, so that people can act on them and know how to take simple measures such as staying out of the sun, keeping windows or shutters closed during peak hours of risk.” Using things to stay cool and hydrated, [and having] Adequate supply of medicine.”
