Climate change | What heat does to us humans

The heat has Germany firmly in its grip these days. With temperatures approaching 40 degrees Celsius, as expected this week in the west and southwest, caution is advised. These temperatures can have life-threatening consequences, especially for certain people. As global warming increases, such heat waves will become more frequent and intense.

Heat is hard work for the human body. The organism strives to maintain a constant temperature of around 37 degrees Celsius, as this is when most cells, proteins, and the immune system function optimally. Extreme fluctuations disrupt these processes. If the human body temperature rises above 42 degrees Celsius or falls below 32 degrees Celsius, it can be fatal.

A rule of thumb is: Danger arises when, under certain conditions, the body absorbs more heat than it can release. This is when body temperature gets out of control and rises rapidly. This threshold is highly individual and depends on age, health, activity, and habituation. At temperatures above 30 degrees Celsius, the body of many Central Europeans experiences significantly more stress cooling itself than at lower temperatures.

The cardiovascular system is under considerable strain in hot weather. People with chronic pre-existing conditions in this area should therefore be especially careful. With increasing age, body temperature regulation slows down, and sweat glands become fewer.

Since older people also feel thirst less frequently , they are at risk of dehydration. According to the Malteser Relief Service, even a one to two percent lack of water in the body can lead to headaches, fatigue, difficulty concentrating, and dizziness. Dehydration is also a risk for babies and young children, and sweat production is reduced.

When the body's sweating capacity reaches its limits, heat builds up: The body temperature rises rapidly – ​​often within 10 to 15 minutes – to over 40 degrees Celsius or more. As a result, the brain swells, leading to headaches, altered consciousness, or unconsciousness – a case for emergency medical services .

Heatstroke, on the other hand, causes a drop in blood pressure. This results in reduced blood flow to the brain, which can lead to symptoms ranging from weakness to nausea and dizziness, even unconsciousness. This, too, is an emergency.

According to the German Society of Neurology, heat also increases the risk of neurological diseases. A study by German neurologists published in the European Heart Journal concludes that the risk of stroke has increased significantly due to increasing nighttime heat. According to estimates by the Federal Environment Agency and the Robert Koch Institute, approximately 3,000 people are expected to have died from heat-related causes in 2023 and 2024, respectively – primarily people over 75 with pre-existing conditions such as dementia, cardiovascular, or lung disease. dpa/nd