For some it is the highest summer feeling. For others, temperatures above 30 degrees, as they are now imminent, are pure torture. And sometimes even dangerous.

It will be hot again in the coming days. After a short cool down, the heat should start again from Sunday. While high temperatures make some people happy, they cause others a lot of trouble – even to the point of serious health problems. Here are the most important answers.

Doctors agree that older people are particularly at risk from heat, especially if they don’t drink enough. The German Medical Association warns that their sense of thirst is reduced, and sometimes they forget to drink altogether. But the heat tolerance can also vary significantly in younger people, according to an overview published by the medical journal.

Acute infections and diseases make you more sensitive, dehydration and disturbances in the electrolyte balance can lead to symptoms. And overzealousness, insufficient familiarization and taking medication also promote illnesses such as sunstroke, heat collapse or heat stroke.

The magic word is “evaporative cooling”. It occurs when sweat evaporates from the skin in hot weather, cooling it down. However, sweat production can be significantly restricted in sick or old people. Medications can also help someone sweat less than they should. In addition, blood circulation in the skin decreases with age, so less heat can be released through the skin.

The body’s self-help mechanism can reach its limits: If it is no longer possible to cool down through sweating at very high temperatures or prolonged heat, there is a risk of heat build-up. Blood vessels in the arms and legs dilate, blood pressure drops. Reduced blood flow to the brain can lead to unconsciousness.

Anyone who is exposed to the sun for a long time without a hat risks heat build-up in the brain. It can also irritate the meninges, causing brain tissue to swell. The consequences: headache and neck pain, nausea, dizziness and vomiting. In extreme cases, it can also lead to cerebral edema, which can lead to unconsciousness and even death, warns the emergency physician Peter Sefrin. Children and older men are particularly at risk – some because they are not yet protected, others because they are often no longer protected by a dense covering of hair.

If the entire body overheats – the temperature can then rise to over 40 degrees within a short time – there is also a risk of brain swelling. Even such a “heat stroke” can be fatal.

Experts recently calculated a significant increase in heat-related mortality for the particularly hot summers of 2018 to 2020: “With an estimated number of around 8,700 heat-related deaths, the year 2018 in particular is of a similar order of magnitude to the historical heat years of 1994 and 2003 (around 10,000 deaths each). “, wrote researchers from the Robert Koch Institute (RKI), the Federal Environment Agency (Uba) and the German Weather Service (DWD) recently in the “Deutsches Ärzteblatt”. The researchers estimate 6,900 heat-related deaths in 2019 and 3,700 in 2020.

According to the Federal Environment Agency (UBA), high air temperatures and intense solar radiation promote the formation of the irritant gas ozone near the ground. On such days, many people suffered from tears, coughs and headaches – regardless of physical activity.

The UBA experts say that the reduced lung function associated with the symptoms usually disappears completely after the heat wave has ended. During physical exertion, however, the ozone can penetrate deep into the lung tissue and damage tissue there and cause inflammation. Such reactions of the lung tissue then only partially recede, there is a risk of respiratory and cardiovascular diseases.