Extreme heat and lack of sleep: the factors that could raise the risk of stroke and dementia, according to an expert

Climate change worsens neurological disorders and raises the risk of stroke or dementia. (Illustrative image Infobae) Climate change can worsen neurological disorders and raise the risk of stroke and dementia in Europe, warned neurologist Ulf Kallweit during the Gastein European Health Forum. Rising temperatures, air pollution, sleep disturbances, and the spread of vector-borne infections are among the factors that can affect brain health. Neurological disorders, from migraines to Parkinson's disease and dementia, affect nearly one in three people over their lifetime. Together with mental health problems, they accounted for an estimated global cost of 1.5 trillion euros in 2019, according to estimates cited by the specialist, who co-chairs the working group on environmental influences of the European Academy of Neurology. Kallweit noted that this scenario can be avoided or mitigated with policies aimed at reducing exposure to extreme temperatures and pollutants, as well as with improvements in urban and housing conditions. His remarks were reported by Euronews. The relationship between high temperatures and stroke is one of the main warnings raised by Kallweit. As he explained, cases increase when the thermometer exceeds 30 °C (86 °F). Heat-related strokes currently account for about 1% of the total, but could reach between 5% and 8% in the next two or three decades, according to his projection. The effect of heat is not limited to daytime hours either. Tropical nights, in which the temperature stays above 20 °C (68 °F), make it difficult for the body to lower its temperature and affect deep rest. Persistent sleep disruption can prevent proper recovery and increase vulnerability to neurological diseases. "If you don't sleep well—not just one night, but over a longer period—there is an enormous increase, let's say, in the risk of suffering a stroke or also of developing dementia," Kallweit said in remarks reported by Euronews. The neurologist placed sleep quality among the aspects that should be considered in prevention, along with reducing noise, nighttime light, and other environmental disturbances. Rising temperatures can also alter the distribution of diseases transmitted by ticks and mosquitoes. Some of these infections affect the nervous system. Lyme borreliosis, for example, can cause neurological complications. Kallweit also mentioned malaria, given the possibility that it could spread to southern Europe in the coming years. Stroke cases increase when the ambient temperature exceeds 30 degrees Celsius. (Illustrative image Infobae) The effects do not fall equally on the entire population. Children, pregnant women, older adults, and people with pre-existing conditions are the groups most exposed to extreme heat and other environmental factors. Vulnerability increases in areas with socioeconomic deprivation, poor housing, or less access to resources that allow people to cope with high temperatures. Research cited by the specialist links economic deprivation to less favorable brain health indicators, such as lower total brain volume and more signs of vascular damage. For Kallweit, unequal access to basic resources deepens this gap. "If it's hot and you can't afford an air conditioner, you suffer more," he argued. Cities concentrate several of these risks. Air pollution, persistent noise, stress associated with housing conditions, and the urban heat island effect can harm well-being and hinder prevention. Climate change, in this context, can deepen gaps already present in lower-income communities. The design of buildings and neighborhoods is part of the measures the neurologist considers necessary. Kallweit called for reviewing architectural guidelines that favor direct sunlight entry and strengthening protections against toxic substances and pollutants. "The way buildings are constructed should be reconsidered," he said. Access to parks, forests, and other green spaces can offer protection for mental and neurological health. According to Kallweit, spending one hour a week in a forest reduces the risk of stroke by 3% and the risk of dementia by 4%. This statement underscores the importance of preserving and expanding green areas near places of residence. Nevertheless, the specialist emphasized that the response cannot depend only on individual decisions. Public policies can determine whether the population has cooler homes, quieter neighborhoods, and cleaner air. These conditions influence the ability to protect rest, maintain healthy habits, and reduce exposure to harmful factors. The warning places urban adaptation and pollution reduction among the measures with the potential to limit the burden of neurological disorders. Kallweit proposed that these changes should accompany the health response to a problem that already affects a large proportion of the population.