During the beginning of summer, several countries around the Mediterranean have had temperatures of up to 40 degrees. Every year thousands of people die due to extreme heat.
Imagine you are in a very hot country. At first, the heat may not feel so dangerous. You think you can hang out by the water and cool off. But after a while you start to get restless. Maybe it would be nice to hike a few hours to the next bay?
But it was warmer than expected, the sun was stronger and it was further to the bay than you thought. At the same time, you see nowhere you can find shade and the small water bottle you had with you is long gone. After just a few hours, you collapse.
At high temperatures, it can happen quickly.
Several tourists have died
One of those researching the effect of climate change on humans is cardiologist Petter Ljungman, associate professor at the Institute for Environmental Medicine at Karolinska Institutet.
High temperatures become an effort for the whole body, not least the circulatory system of the heart and the body’s blood vessels. The body then tries to lower the heat by sweating and opening up vessels.
This leads to the heart having to beat both faster and harder – which results in an increased load on the heart.
If you already have, for example, a heart and vascular disease, you may have more problems. You can have epileptic seizures, become unconscious and have cardiac arrest.
But it’s not just high temperatures that matter. Even how humid it is outside matters for the body.
Sweating is not as effective in humid climates because the moisture cannot be absorbed into the air, it is already saturated with water vapor, says Ljungman.
Tourist walks next to a restaurant where water vapor is sprayed in Athens. In the background is the Acropolis Hill, which during June was forced to close several days in a row due to temperatures rising above 40 degrees. Image from 13 June.
Tourist walks next to a restaurant where water vapor is sprayed in Athens. In the background is the Acropolis Hill, which during June was forced to close several days in a row due to temperatures rising above 40 degrees. Image from 13 June.
Photo: Petros Giannakouris/AP/TT
The heat can also make one confused and nauseous. It becomes more difficult to make complex decisions, such as which route to take during a hike – a decision that sounds simple but requires weighing several different factors.
In Greece, several tourists have died during the early summer heat wave. Several of them are said to have died when they decided to walk in the middle of the day under the scorching sun. As noted BBC profiler Michael Mosley.
A cascade of different things happens in the body when you suffer from heat stroke. You get various chemical changes in the body which means that you can, for example, start to leak fluid into the lungs or into the brain. The intestines are also affected so that the body lets more toxins from the intestinal contents into the blood, says Ljungman.
Late symptoms of heat stroke are when the body undergoes various chemical changes at the cellular level.
Late symptoms of heat stroke are when the body undergoes various chemical changes at the cellular level.
Photo: Anna-Lena Lindqvist/TT
You can do that yourself
What you can do yourself in extreme heat is to drink a lot, get salt, wear loose-fitting clothes and avoid being outside when it’s at its hottest.
If you come from Sweden to a warmer country, it takes a few days physically before you adapt, says Ljungman.
In a way, tourists can be extra vulnerable, even though they can often be better off than local people in warm places, he believes.
It’s about behavior and expectations. You may have paid a lot of money for your holiday and thought you should do one and the other. But then you haven’t expected the heat and don’t have the same knowledge, understanding or habit of what to do when it’s extremely hot. So it is probably not a coincidence that tourists are affected to a greater extent.
But it is not possible to say any general temperature or limit for when the heat starts to become dangerous. Partly because it is individual how you handle heat, and partly because factors such as humidity and wind come into play.
Facts: Extreme heat
The extreme heat kills thousands of people every year. Most deaths occur in Asia, but as a percentage of the population, the figure is higher in Europe, especially in the southern and eastern parts.
In 2018, for example, 700 people are estimated to have died as a result of the heat in Sweden, and over 70,000 deaths are linked to the hot summer that prevailed in Europe in 2003.
Source: Study published in Plus Medicine