Once the battle is won, the thermostat is turned down – and you sweat.
What you see: The woman is asleep. A drop of sweat on her forehead shows the body releasing heat again.
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Fever isn't the illness. It's your body fighting back.
What you see: A white blood cell in calm light.
02 · The myth
Fever is the body's defence – not the illness itself
Many believe
The fever is the illness.
Why many believe it
The fever is what you feel most: you freeze, sweat and feel weak.
What is right
Fever is not an illness in itself. It is usually part of the body's defence against an infection, and the body itself turns up the temperature. The illness is what lies behind it, most often a virus.
03 · What you can do
What you can do yourself
Rest and take it easy.
Drink plenty. With a fever the body loses more fluid than usual.
Do not dress too warmly, but avoid getting cold. A slightly cool room is good.
04 · See a doctor
Contact a doctor if …
You have severe trouble breathing, chest pain lasting more than five minutes, or become confused or hard to wake – call 113 in Norway or your local emergency number.
You have a fever and get small red-purple spots that do not fade when you press a glass against the skin, or a fever and a stiff neck – call 113 in Norway or your local emergency number.
You get much worse quickly, or feel limp and very unwell – call the out-of-hours medical service (legevakt, 116 117 in Norway) or your local urgent care service.
You have an infection and develop laboured breathing, a racing pulse or clammy skin – call the out-of-hours medical service (legevakt, 116 117 in Norway) or your local urgent care service straight away.
The fever has lasted more than three days and you still feel unwell – contact your GP (regular doctor).
In children
Your child has a fever and gets small red-purple spots that do not fade when you press a glass against the skin, or has a fever and a stiff neck – call 113 in Norway or your local emergency number.
Your child has a seizure for the first time, or a seizure lasts more than five minutes, is stronger on one side of the body or comes back within 24 hours – call 113 in Norway or your local emergency number.
Your baby is younger than six months and has a fever – call the out-of-hours medical service (legevakt, 116 117 in Norway) or your local urgent care service.
Your child is limp and very unwell, or responds to you less than usual – call the out-of-hours medical service (legevakt, 116 117 in Norway) or your local urgent care service.
Your child is struggling to breathe, cannot drink, or is peeing much less often than usual – call the out-of-hours medical service (legevakt, 116 117 in Norway) or your local urgent care service.
The fever has not come down after two to three days – contact your GP (regular doctor).
Your doctorfor everyday health problems and when it can wait
This is general advice. If you are unsure, contact an out-of-hours doctor.
05 · Simplified
Simplified illustration – not to scale
The film is made with AI and shows the body more simply than it is. This is what we simplified:
The signal molecules are shown as golden particles of light. In reality they are molecules far too small to see.
The «thermostat» is an image for a small area deep in the brain (the hypothalamus) that controls body temperature.
Blood vessels, cells and nerve cells are not shown at their true sizes relative to each other.
Viruses are shown as teal spheres. Real viruses are much smaller than blood cells.
That the heat makes life harder for viruses and bacteria is a theory. It is one of several possible explanations of why fever helps, and it is not certain how much it matters in humans.
Headache and migraine
