36 degrees – and it’s getting even hotter? That’s true: Germany’s summers have become significantly warmer on average since measurements began at the end of the 19th century. What does that mean for health?
A year ago even Hamburg tore the 40 degree mark in July. For the German Weather Service it was a “real rarity”. According to scientists, hot days and tropical nights that can cause a heat wave are a serious health hazard.
The body can acclimate within limits. But this is much more difficult for children, sick and old people in particular than for healthy adults.
When does heat become dangerous for humans?
A rule of thumb is: It becomes dangerous when the body absorbs more heat than it can release again. Because then the body temperature gets out of control and rises rapidly. This limit is very individual and depends on age, state of health, activity and habituation. At over 30 degrees, the body of many Central Europeans has significantly more stress to cool itself down than at lower temperatures. It usually takes several days to get used to high temperatures.
Why can heat, in extreme cases, lead to death?
Heat means hard work for the human body. Because the organism tries to keep its temperature constant around 37 degrees. Most cells, enzymes, proteins and the immune system then work optimally. In the event of extreme fluctuations, all of these processes are disturbed. If the human body temperature rises above 42 degrees or falls below 32 degrees, it can be fatal.
How does the body’s air conditioning work?
In order to counteract organ damage, the body increases its cooling system when it is hot and releases liquid and salts – the sweat. This cools the skin through evaporation. High humidity slows this process down, so sweating is less efficient in humid weather. When the body is warmer than its surroundings, it can also radiate heat – like a lightbulb heats up its surroundings. When it’s hot, blood vessels dilate, causing blood pressure to drop. The heart increases its pumping capacity, and breathing can also accelerate. Brain performance can decrease due to reduced oxygen supply.
What is a heat wave?
For the German Weather Service (DWD), a heat wave is an extreme event that can damage human health, ecosystems and infrastructure. Internationally, there is no uniform definition of the term. The Weather Service defines a heat wave as a multi-day period of unusually high thermal stress. The parameters include not only air temperature, but also humidity (humidity), radiation from the sun, earth and atmosphere, and wind. In our latitudes, heat waves often occur in connection with persistent summer high pressure areas.
What do “hot day” and “tropical night” mean?
The air temperature on so-called hot days is 30 degrees or more. In 2022, for example, there were 17 hot days in Germany, up to 20 were counted in previous years. On a “tropical night” the thermometer does not drop below 20 degrees. For the Federal Environment Agency, heat waves are phases in which hot days and tropical nights alternate over a longer period of time. This combination is considered extremely problematic from a health point of view, since people are not only exposed to extreme heat during the day, but the body cannot recover sufficiently well at night due to a lack of cooling.
When were the last noticeable heat waves in Germany?
The German Weather Service cites the year 2003 as an example of a very significant wave. At that time, there were maximum values of over 35 degrees on eleven days in a row, especially at the beginning of August in southern Germany. This “summer of the century” with an average temperature of 19.7 degrees has led the statistics since measurements began in 1881. According to DWD data, the summers of 2018 (19.3 degrees), 2019 (19.2) and 2022 (19.2 degrees) are also considered unusually warm. Meteorologists consider the higher average temperatures in summer to be “soon to be typical” in times of climate change.
What were the consequences?
According to the German Weather Service, the heat waves of summer 2003 led to an estimated 7,600 additional deaths in Germany. Researchers for the Robert Koch Institute calculated that the unusually high summer temperatures in recent years have repeatedly led to a statistically significant number of deaths. According to this, there were around 8,300 heat-related deaths in 2018, around 6,900 in 2019, around 3,600 in 2020 and around 4,500 in 2022. Overall, a certain adjustment to the higher temperatures can be observed over the past 30 years. However, heat events remained a significant threat to the health of people in Germany.
Who is particularly at risk in the heat?
High outside temperatures can put a lot of strain on the cardiovascular system. People with chronic pre-existing conditions in this area should therefore be particularly careful. As we age, body temperature regulation slows down and there are fewer sweat glands. Also, because older people are less likely to feel thirsty, they are at risk of becoming dehydrated. According to the Malteser relief service, even one to two percent too little water in the body can lead to headaches, tiredness, poor concentration and dizziness.
Among other things, sweat production is lower in children. Babies and small children in particular suffer more quickly from heat complaints – dehydration is also a risk here.
People who do heavy physical work outdoors are also at risk when it is very hot. The same applies to people who find it difficult to help themselves, such as those in need of care, the mentally ill, drug addicts and the homeless.
What are typical heat disorders?
SUNSTRIKE: If the head is exposed to direct sunlight for too long without a cap, hat or scarf, this can lead to irritation of the meninges. In severe cases, brain swelling occurs. Signs of this can be headache, nausea with vomiting, fever, sometimes also disturbances of consciousness and seizures.
HEAT STROKE: When it’s hot, the body’s capacity to sweat can reach its limits. Then heat builds up: the body temperature rises quickly – often within 10 to 15 minutes – to over 40 degrees or more. As a result, the brain swells, causing headaches, changes in consciousness, or loss of consciousness. This is an emergency medical service case.
HEAT COLLAPSE: Excessive heat causes blood pressure to drop. The result is a reduced cerebral blood flow, which can lead to a feeling of weakness, nausea and dizziness to unconsciousness. This is also an emergency.
HEAT SPARMS: Those who do physical exertion in the heat, for example when doing sports or gardening, usually sweat profusely. This can lead to a lack of fluid and electrolytes such as sodium or potassium in the body. They help control nerve and muscle function. When there is a lack of electrolytes, the muscles react with cramps or muscle pain.
HEAT RASH: When sweat is unable to adequately evaporate through poorly breathable or tight clothing, it clogs the exits of the sweat glands. The result is small, often itchy or burning blisters.