25-09 - Flipbook - Page 26
Mi n i str i es
"Thermoregulation is a brain function and can be disrupted, if certain parts of the brain are
not functioning properly," says Sisodiya. In some forms of multiple sclerosis, for instance, the
core body temperature appears to be altered. In addition, some drugs that treat neurological and psychiatric conditions such as schizophrenia affect temperature regulation, leaving
those taking them more vulnerable to heatstroke, or hyperthermia as it is known medically,
and at a greater risk of heat-related death.
Heatwaves 3 and elevated nighttime temperatures especially 3 can affect people's sleep,
affecting our mood and potentially worsening the symptoms of some conditions. "For many
people with epilepsy, poor sleep can increase the risk of having seizures," says Sisodiya.
Evidence suggests that hospital admissions and mortality rates among people with dementia also increase during heatwaves. Part of this may be due to age 3 older people are less
able to regulate their body temperature 3 but their cognitive impairment may also mean
they are less able to adapt to extreme heat. They may not drink enough, for example, or
forget to close the windows, or go out into the heat when they shouldn't.
Rising temperatures have also been linked to an increase in stroke incidents and mortality.
In one study that analysed stroke mortality data from 25 countries, researchers found that
out of 1,000 deaths from ischemic stroke, the hottest days contributed two excess deaths.
"That may not seem like a lot," says Bethan Davies, a geriatrician at University Hospitals Sussex, in the UK. "But given that there are seven million deaths from strokes a year worldwide,
heat may well be contributing to over 10,000 additional stroke deaths per year." She and
her co-authors warned that climate change is likely to exacerbate this in years to come.
A disproportionate share of the burden of heat-related stroke will be in middle- and lowincome countries, which are already most affected by climate change and experience the
highest rates of stroke. "Rising temperatures will exacerbate health inequalities both between and within countries and social groups," says Davies. A growing body of evidence
suggests that older people as well as those with a low socioeconomic position are at an increased risk for heat-related mortality.
A hotter world is also harming the neurodevelopment of the very youngest. "There is a link
between extreme heat and bad pregnancy outcomes such as premature births," says Jane
Hirst, professor of global women's health at Imperial College London in the UK. One recent
systematic review of the scientific research found that heatwaves are associated with a
26% increase in preterm births, which can lead to neurodevelopmental delays and cognitive impairments.
"However, there is a lot we do not know," adds Hirst. "Who is most vulnerable and why? Because clearly, there are 130 million women who have babies every year, a lot of them in
hot countries, and this does not happen to them."
What we're seeing today in people with neurological disorders could become relevant for
people without neurological disorders as climate change progresses – Sanjay Sisodiya
Excessive heat due to climate change may also put additional strain on the brain, leaving it
