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Author Topic: Why sweat when running a fever?  (Read 9278 times)

Evan Boyar

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Why sweat when running a fever?
« on: 27/05/2009 21:30:03 »
Evan Boyar  asked the Naked Scientists:
   
Dear Naked Scientists,

I have a question about fevers. If the point of getting a fever is to denature a virus' enzymes and proteins making it function less efficiently and easier to kill (if you consider it alive in the first place), why do we sweat when we have a fever? Our body causes the fever, so why does our thermoregulatory system work against itself trying to cool you at the same time as heat you?
   
-A 15 year old "yank" named Evan

P.S., would it be possible to send an email containing an audio question to be played on the show to avoid  the excessive cost of trans-continental phone calls?

What do you think?

Chemistry4me

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Why sweat when running a fever?
« Reply #1 on: 28/05/2009 05:25:30 »
I can think of two reasons, the blood circulation and respiration rates increases during a fever, and when we sweat we are eliminating toxins from the body. 

Bored chemist

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Why sweat when running a fever?
« Reply #2 on: 28/05/2009 17:54:03 »
A third possible reason is that  the body has two (or more) thermoregulatory systems and they don't talk to eachother.
One sysem knows it's trying to raise the body temp to cook the bugs. The other just sees the body getting hot and tries to reduce the temperature by sweating.

Variola

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Why sweat when running a fever?
« Reply #3 on: 28/05/2009 19:33:11 »
Best guess

Sweating when we have a fever is a regulatory mechanism to ensure the fever doesn't get too high, but is high enough to help fight the infection. If we ran a fever the temperature may steadily climb until its at the level where we sustain cellular damage.
Hence when children get fevers the emphasis is to bring it down, as they are susceptible to febrile convulsions.
As BC said we also sweat out toxins, as I understand it,it is toxins released by virus/bacteria, and also chemicals from the immune system,that trigger the hypothalamus to raise our core temperature, so it could be that these toxins are released through sweat. Perhaps it is a negative feedback loop, the higher the level of pathogen toxins the higher the temperqure is set, or the more likely the hypothalamus is to raise the temp. The when the temp is raised, and we sweat, toxins are passed out, leaving a lower level in the body and thus our temp drops again. his would account for the temperature spikes common with infection.... but that really is just a guess on my part.

Bored chemist

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Why sweat when running a fever?
« Reply #4 on: 28/05/2009 20:59:16 »
"As BC said we also sweat out toxins, "
Oh no I didn't. I don't think that sweating is a significant excretion pathway for most toxins.
Traces of some materials leave that way but other paths are much more effective.

Variola

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Why sweat when running a fever?
« Reply #5 on: 28/05/2009 21:10:27 »
"As BC said we also sweat out toxins, "
Oh no I didn't. I don't think that sweating is a significant excretion pathway for most toxins.
Traces of some materials leave that way but other paths are much more effective.

I do beg your pardon BC....it was C4M that said that, my bad!
No true most toxins leave via the kidneys and urine, however I am still intrigued as to whether the sweating does provide a feeback loop in terms of fever, and not just in general regulatory terms.
I am also intrigued as to why viruses typically seem to produce a higher fever than bacteria. I say typically as its not true in every case, my in my experience, and my GPs experience it does seem to follow a pattern.
I'm wondering if virus transcription needs a hgher level of temperature to disrupt it??Particularly as some can decide whether to lyse, retro or hide.

DrN

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Why sweat when running a fever?
« Reply #6 on: 28/05/2009 21:18:13 »
Its interesting that local infections make the local area red and warm, so I guess it figures that systemic infections would make the whole body red and warm! Must be an immunological reaction one way or another?

 

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