Lower fever: when is it useful and when not? | NDR.de – Guide

Status: 01/24/2023 4:25 p.m

Fever can be a sign that the body is defending itself against an invader. The fever can be reduced with medication. But does that make sense in any case? So far, there are no reliable general statements about this.

The human body normally has a body temperature of 36 to 37 degrees. If the temperature in adults rises to up to 38 degrees, doctors speak of an elevated temperature, which is a fever. It becomes life-threatening when the body temperature exceeds 42 degrees, because this destroys protein building blocks in the body. Fever is not a disease, but a symptom – and even a useful weapon of the body against viruses and bacteria.

Fever accelerates defense processes in the body

When infected, pathogens and inflammatory messengers can cause our brain to act like an internal thermostat, raising the body temperature setpoint. At the beginning of the fever, the body does not sweat – on the contrary: hands and feet are cold, those affected freeze and get chills. The brain controls that the blood flow to the periphery of the body is reduced – so the heat stays in the organs and in the blood.

Invaders such as viruses or bacteria multiply best at 37 degrees. If the body gets hotter due to fever, the proteins of some pathogens clump together. As a result, they can no longer reproduce as well or die off. In the case of illness, the immune system runs at full speed. The lymphocytes have an important task: These immune cells detect viruses or bacteria in the blood and fight them. To do this, they migrate to the site of infection and fend off the pathogens there. Fever can speed up this process. Because then so-called heat shock proteins are released – a turbo boost for the lymphocytes, because they then become faster and can fight the viruses faster.

Fever is basically a useful defense reaction of the body to an infection and does not always have to be reduced. Usually, the fever goes down on its own within a few days. If the fever lasts longer or if the temperature rises above 39 degrees, it is advisable to see a doctor. This also applies if the fever suddenly rises again after it has subsided.

High fever is more dangerous for older people with pre-existing conditions

In older people with comorbidities or babies, a high fever can become dangerous more quickly and must therefore be reduced more quickly than in adults without previous illnesses. Because most processes in the body work best at 37 degrees. If the body is permanently significantly hotter, this can be dangerous. Cardiac arrhythmias or dehydration can be the consequences. In the worst case, the severe overheating can lead to organ failure. In addition, if the fever persists, the cause must be sought in order to rule out life-threatening diseases such as blood poisoning (sepsis).

Fever in children: what to look out for?

In children, one speaks of fever from 38.5 degrees, in infants under three months of 38 degrees. A medical visit is necessary:

  • if the fever rises above 39 degrees (in infants above 38 degrees).
  • the fever lasts longer than three days
  • Fever occurs repeatedly or in flares
  • when the child seems listless
  • when the child is restless
  • when the child seems confused
  • if the child does not want to drink for a long time
  • in case of vomiting
  • with diarrhea
  • with abdominal pain
  • with skin rash

Little research has been done on the effect and benefits of fever reduction

There is no general answer to the question as to the temperature from which fever must be reduced with medication. So far, there is no meaningful, evidence-based data on the benefit of fever reduction in adults and children. In a big one review work, which was published in 2022, scientists analyzed 42 studies on the subject and came to the conclusion: “Fever therapy does not appear to affect the risk of death and serious adverse events.” There is no reliable data on the question of whether reducing fever prolongs the course of the disease.

There are no clear guidelines for children either: The German Society for Pediatrics and Adolescent Medicine does not specify an absolute limit from which fever reduction is necessary. The professional association of paediatricians advises parents, in consultation with a doctor, to give their children antipyretics only when the temperature is well above 39 degrees.

Reduce fever with painkillers such as ibuprofen or acetaminophen

Drugs to reduce fever can help to alleviate the feeling of illness. Drugs such as paracetamol, ibuprofen or the prescription Novaminsulfone are effective, reducing headaches and body aches and also being effective against fever. The drugs act in the brain and cause the target value for body temperature to drop. The effects usually last for up to six hours. It should be noted that only the symptoms are alleviated. An improvement is “feigned”. The body still works against the pathogens and needs rest. Overexertion should therefore be avoided at all costs.

Important to know: For every degree of increase in body temperature, you have to drink an extra liter of fluid a day. At 39.5 degrees, that means a total of around five liters of water a day. If you can’t do that, it’s better to lower your fever.

Reduce fever with home remedies

Physical fever reduction, for example, can be done with calf wraps. Sheets moistened with vinegar water are wrapped around the calves for a few minutes. Wetting the bed sheet can also provide relief. However, the cooling only works for a short time. The command to increase body temperature is still active in the brain.

Temperature measurement – preferably in the Po

The best way to measure fever is in the bottom. Because you measure the core body temperature and only that is interesting. In the mouth or under the armpit, there are large fluctuations and lower temperatures than inside the body. In trained hands, measuring the fever with a special thermometer in the ear can also provide exact results. But even a little earwax or the wrong angle can falsify the result.

experts on the subject

Further information

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