Why do I feel cold and shiver when I have a fever?

Wednesday 22nd July 2009
Submitted by Luis Villazon
Jim Taylor, Spain

A fever is when your body increases its internal thermostat, found in the hypothalamus. If you exercise hard or it’s a hot day, your body temperature might increase, but the thermostat remains at around 36.8°C. When you feel hot the hypothalamus tries to correct this with sweating and increased blood flow to the skin. But with a fever, it is the thermostat that has risen. This means your body temperature is now below 36.8°C, so you feel cold and shiver, to try and raise your temperature. The higher body temperature may help fight infection by speeding white blood cell production and slowing bacteria reproduction.

Why do mosquito bites itch so much?
previous qanda Article
Is the human race still getting taller?
next qanda Article
Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

Bulletproof vests are designed to disperse the round’s energy and deform the slug to minimise blunt force trauma. Hard body armour is made of strengthened steel plates. It is strong and...

When you enter a search in Google, you aren’t actually searching the web, you are searching Google’s index. This is compiled and continuously updated by automatic programs, called...

The function of the iris is to limit the amount of light that passes through the lens to the retina. To make the iris opaque, it is coated with the pigment melanin, in varying degrees for each of...

It looks like any other tourist-friendly black cab, but that’s exactly the point. This fuel cell hybrid taxi has the same cabin space and styling as any other black cab. But packed into the...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...