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

No. At least, not in the popular sense that creative people are more ‘right-brained’ than logical or analytical people are: a study that scanned the brains of over 1,000 people found...

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...

Trees release oxygen when they use energy from sunlight to make glucose from carbon dioxide and water. Like all plants, trees also use oxygen when they split glucose back down to release energy to...

Because of the orientation and tilt of their orbits, the eight major planets of the Solar System can never come into perfect alignment. The last time they appeared even in the same part of the...

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...

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...

We use cookies to improve your experience of our website. Cookies perform functions like recognising you each time you visit and delivering advertising messages that are relevant to you. Read more here