A year ago, even Hamburg reached a temperature of over 40 degrees Celsius in July, which was a rare exception according to the German Weather Service. Hot days and tropical nights, which can lead to heatwaves, pose a serious risk to health, as scientists point out. Although the body can adapt to heat to a certain extent, this is much more difficult for children and sick and elderly people than for healthy adults.
When is heat dangerous for humans?
There is a rule of thumb that says that heat becomes dangerous when the body absorbs more heat than it can release. In such cases, the body temperature gets out of control and rises rapidly. This limit is individual and depends on age, state of health, activity and habituation. At temperatures above 30 degrees Celsius, Central Europeans have more difficulty cooling themselves down compared to lower temperatures. Adaptation to high temperatures usually takes several days.
Why can extreme heat even lead to death?
Heat places an enormous strain on the human body, as the organism strives to maintain a constant body temperature of around 37 degrees Celsius. Extreme temperature fluctuations disrupt many cells, enzymes, proteins and the immune system. If the body temperature rises above 42 degrees Celsius or falls below 32 degrees Celsius, this can be fatal.
How does the body’s air conditioning system work?
In the heat, the body increases its cooling to prevent organ damage by releasing fluid and salts – sweat. This leads to cooling of the skin through evaporation. This process is slowed down in high humidity, which is why sweating is less effective in humid weather. If the body is warmer than the ambient temperature, it can also radiate heat, similar to the way a light bulb heats its surroundings. In high heat, the blood vessels dilate, which leads to lower blood pressure. The heart increases its pumping function and breathing can also be accelerated. Reduced oxygen supply can lead to a decrease in brain performance.
What is a heatwave?
A heatwave is defined by the German Weather Service (DWD) as an extreme event that can damage human health, ecosystems and infrastructure. There is no uniform international definition of the term. The DWD defines a heatwave as a period of several days with unusually high thermal stress. Not only the air temperature plays a role here, but also the humidity (sultriness), the radiation from the sun, earth and atmosphere as well as the wind. In our latitudes, heatwaves often occur in conjunction with persistent high pressure areas in summer.
What do “hot day” and “tropical night” mean?
“Hot day” means an air temperature of 30 degrees Celsius or higher. In 2022, for example, there were 17 hot days in Germany, compared to up to 20 in previous years. A “tropical night” occurs when the thermometer does not fall below 20 degrees Celsius. The Federal Environment Agency defines heatwaves as phases in which hot days and tropical nights alternate over a longer period of time. This combination is considered extremely problematic for health, as people are not only exposed to extreme heat during the day, but are also unable to recover sufficiently at night due to a lack of cooling.
When was the last time there were noticeable heatwaves in Germany?
The German Weather Service cites 2003 as an example of a particularly notable heatwave. At the beginning of August, southern Germany recorded maximum temperatures of over 35 degrees Celsius for eleven consecutive days. This “summer of the century” with an average temperature of 19.7 degrees Celsius has led the statistics since measurements began in 1881. According to DWD data, the summers of 2018 (19.3 degrees), 2019 (19.2 degrees) and 2022 (19.2 degrees) are also considered unusually warm. Due to climate change, higher average summer temperatures are considered increasingly typical by meteorologists.
What were the consequences?
The heat waves of summer 2003 led to an estimated 7600 additional deaths in Germany, according to the German Weather Service. The Robert Koch Institute has calculated that the unusually high summer temperatures have led to a statistically significant number of deaths several times in recent years. In 2018, there were around 8300 heat-related deaths, in 2019 around 6900, in 2020 around 3600 and in 2022 around 4500. Although some adaptation to higher temperatures has been observed over the last 30 years, heatwaves remain a significant threat to the health of people in Germany.
Who is particularly at risk in the heat?
People with chronic cardiovascular diseases are particularly at risk in hot weather. With increasing age, the regulation of body temperature slows down and there are fewer sweat glands. Older people also feel thirsty less often, which can lead to dehydration med.: Volumenmangel der extrazellulären Flüssigkeit, u.a. des Blutplasmas – dem Körper wird weniger Flüssigkeit zugef.... Just one to two percent water deficiency in the body can cause headaches, tiredness, concentration problems and dizziness. People who work physically hard are also at risk in hot weather. The same applies to people who are dependent on help, such as those in need of care.
In general:
Avoid direct sunlight, cover your head and neck and avoid strenuous physical activity. Keep your rooms cool and only ventilate early in the morning and at night when it is cooler. During the day, you should lower the blinds and keep the doors closed. And above all: drink plenty of fluids!
If you need support to drink enough regularly, for example in the form of a drinking reminder, the LAQA SmartCup can be a good companion on hot summer days. Contact us, we will be happy to advise you!
