Spain has just emerged from a 21-day heatwave that gripped Madrid, Barcelona and Zaragoza, posing a health risk far greater than the actual temperatures, according to Julio Diaz, a researcher at Madrid’s Carlos III Health Institute.
Doesn’t the heat itself cause deaths during a heat wave?
“The impact of heat on health is far beyond just temperature… The effects can be felt across income levels, age groups, socio-economic status, health care and different cultural attitudes towards heat,” Diaz says.
“We divided Spain into 182 regions… and in each, we determined the temperature at which people start dying because of the heat. In Seville, 40 degrees Celsius (104 Fahrenheit) is not even classified as a heatwave, while in A Coruña (in northwestern Spain), the temperature that defines a heatwave is 26 degrees.
“When there is extreme heat, only 3.0 percent of deaths are due to heat stroke. Heat takes more lives by aggravating other diseases.”
Why are the first heat waves the deadliest?
“In the first heat wave (of the year), many more people are likely to be vulnerable (to death) than in the second, because it hits the most vulnerable, leaving the less vulnerable in the second and even fewer in the third… This is why the first heat wave always has a greater impact on mortality. This is what we call in epidemiology the ‘harvest effect’.”
Why is standard of living a factor?
“It’s clear that the impact of heat is much greater in poorer areas.
“Experiencing a heatwave in a room with three people, with one window and without air conditioning or a fan, is not the same as going through the same situation in a villa with a swimming pool.
It’s not a question of having air conditioning or not, but about being able to turn it on. During this summer, the price of electricity in Spain skyrocketed.”
What is heatstroke?
“Heatstroke occurs when a person is exposed to high temperatures… and their body is not able to regulate that temperature. If you go out in the sun at 42°C or exercise at that temperature, your body – no matter how much it sweats, which is the main mechanism for regulating heat – is unable to reduce and maintain its temperature at 37°C.
When your body is below 37 degrees Celsius … your organs stop working properly, including your brain. Then hyperthermia sets in and the person can die.”
What is ‘heat culture’?
“In 2003 there was a terrible heatwave in Europe and 70,000 people died in 15 days. People were not prepared and there was no prevention plan, which meant it had a very bad impact on mortality. Now no one doubts that heat kills.
But people adapt. Between 1983 and 2003, for every degree above the temperature classified as a heatwave, mortality in Spain increased by 14 percent. But after 2003, it barely increased by three percent.
In a city like Madrid you never used to see older people wearing shorts, but nowadays they all wear shorts – you see them wearing hats and going out for a walk with a water bottle.
In places where people are accustomed to heat waves, there are now a lot more air conditioning units and secondly, homes are more adapted to deal with this heat.
People don’t go out after 3:00 p.m., so Spain has a siesta. And in the southern Andalusia region, villages are painted white and the streets are wide so the air can circulate freely.”
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