Fever is exhausting but useful.

Fever – why it helps the body

People who catch a cold, flu or other infection often develop a fever – a useful symptom. The high temperature enables the body to produce more white blood cells, which the immune system needs to fight bacteria or viruses. Reducing the fever immediately is therefore counterproductive.

At what point is it fever?

The body temperature of a healthy person measures around 37 degrees. Fever is spoken of after 38 degrees. If pathogens have entered the body, they and the body's own messenger substances can influence the hypothalamus – the brain region responsible for heat balance. The body temperature then rises in several stages.

What happens when the body has a fever?

1. To curb heat loss, our blood vessels constrict. Our skin is pale, cool and dry.
   
2. At the same time, we start to shiver and get cold, and our muscles begin to tremble. The chills that come with fever ramp up heat production.
   
3. Our body heat rises, our skin feels hot and our cheeks glow. The peak temperature is reached.
   
4. Once the heat-sensitive pathogens have been fought off, the body adjusts back to its normal temperature. The blood vessels dilate. Heavy sweating helps the body to cool down.
   

Symptoms with fever

When we have a fever, our heart and breathing rates accelerate, putting the body under greater strain. The high temperature is a clear indication of fever. Feeling weak and weary are also typical symptoms and a sign that (bed) rest is called for. Provided nothing unforeseen happens, the body returns to normal after a few days.

Be sure to see a doctor

However, if the fever lasts longer than 3 days or occurs shortly after a trip to the tropics, it's essential to see a doctor. Also if the body’s temperature exceeds 40 degrees in adults or 39 degrees in children. Babies up to 3 months of age with fever also need medical treatment.