Why Do We Sweat in Cooler Temperatures?

[zorro]

Our normal body temperature is 37 degrees celsius. Then why do we perspire even at a temperature lower than 37 degrees (say 30 degrees) ?

 

[G037H3]

sweating is to cool the body...

perspiration occurs at that low of a temperature? news to me

 

[zorro]

Even if we don't perspire , we feel quite uncomfortable ( 25 degrees is the comfort zone ). According to my logic 37 degrees should be the comfort zone.

 

[G037H3]

but then internal body temperatures would be too high...our skin is a decent insulator

 

[Ken Natton]

Well, Abdul Quadeer, I don’t really have any particular expertise in this field, but I’d have to suggest to you that you might be well advised to follow the advise of your own thread title. As G037H3 pointed out, the function of sweating is to lose heat. That is, heat generated by the activities of the body, not heat coming from the ambient surroundings.

 

[zorro]

but then internal body temperatures would be too high...our skin is a decent insulator

Why will they be? Our body's normal temperature is 37 degrees. So if outside temp is same then our body should be in equilibrium with environment i.e. there should not be any feeling of uncomfortableness.

 

[zorro]

but I’d have to suggest to you that you might be well advised to follow the advise of your own thread title. As G037H3 pointed out, the function of sweating is to lose heat. That is, heat generated by the activities of the body, not heat coming from the ambient surroundings.

Thanks for your advice. But I'm afraid you did not understand my question. I did not ask what is the function of sweating.

 

[Ken Natton]

I did not ask what is the function of sweating.

No, but you wondered why the body sweats when the ambient temperature is lower than body temperature. That is like wondering why a piece of metal fresh from the furnace glows red when the ambient temperature is much lower.

 

[zorro]

That is like wondering why a piece of metal fresh from the furnace glows red when the ambient temperature is much lower.

That is a nice point!

 

[Evo]

This might help.

http://www.ccohs.ca/oshanswers/phys_agents/thermal_comfort.html

 

[JaredJames]

Think about this:

I live in the UK, relatively low average temperatures of 10 to 20 degrees celsius. I find this comfortable. Yet when I travel to Florida I start sweating due to the higher ambient temperatures, but the American next to me hasn't even noticed the heat, they are comfortable.

Our body develops to regulate our internal temperature based on the ambient temperature. At this time, it is 18 degrees around me, my body is generating enough heat to maintain 37 degrees internally, compensating for the external temperature. The moment you change the ambient, my body can no longer regulate properly without time to adjust (if the ambient becomes too low your body can't compensate quick enough, your internal temperature drops and hypothermia sets in).

A person in a climate where temperatures are 40 degrees plus throughout summer won't feel the heat as much as I would. They may be able to walk around in trousers quite comfortably whilst I am in as little as possible trying to stay cool all the while sweating as my body tries to adjust to compensate for the ambient temperature.

So to answer your question, for a person in a 10 degree ambient temperature, their body will be producing enough heat to maintain 37 degrees internally. However, if you increase the ambient to 20 degrees, their body is then not required to produce as much heat and so until you adjust, you are producing too much heat and become too warm and so start to sweat. If you do not sweat (and can't cool yourself / your body can't regulate it's temperature), as with hypothermia your body temperature will fluctuate from the required 37 degrees and you will become seriously ill. All the time, the ambient is 17 degrees lower than your internal temperature.

 

[zorro]

Think about this:

I live in the UK, relatively low average temperatures of 10 to 20 degrees celsius. I find this comfortable. Yet when I travel to Florida I start sweating due to the higher ambient temperatures, but the American next to me hasn't even noticed the heat, they are comfortable.

Our body develops to regulate our internal temperature based on the ambient temperature. At this time, it is 18 degrees around me, my body is generating enough heat to maintain 37 degrees internally, compensating for the external temperature. The moment you change the ambient, my body can no longer regulate properly without time to adjust (if the ambient becomes too low your body can't compensate quick enough, your internal temperature drops and hypothermia sets in).

A person in a climate where temperatures are 40 degrees plus throughout summer won't feel the heat as much as I would. They may be able to walk around in trousers quite comfortably whilst I am in as little as possible trying to stay cool all the while sweating as my body tries to adjust to compensate for the ambient temperature.

So to answer your question, for a person in a 10 degree ambient temperature, their body will be producing enough heat to maintain 37 degrees internally. However, if you increase the ambient to 20 degrees, their body is then not required to produce as much heat and so until you adjust, you are producing too much heat and become too warm and so start to sweat. If you do not sweat (and can't cool yourself / your body can't regulate it's temperature), as with hypothermia your body temperature will fluctuate from the required 37 degrees and you will become seriously ill. All the time, the ambient is 17 degrees lower than your internal temperature.

If we keep the temperature of whole Earth constant at 37 degrees. Our body will take some time to adjust to it and consequently we feel comfortable. Is this right?

 

[JaredJames]

If we keep the temperature of whole Earth constant at 37 degrees. Our body will take some time to adjust to it and consequently we feel comfortable. Is this right?

Why? As per my previous post, your body is producing heat. That amount is determined by the ambient (within reason).

37 ambient is too high. You are implying your body wouldn't be producing heat at that temperature.

Your body will however compensate for the ambient to ensure 37 internal is maintained. There is no difference between being comfy at 37 ambient or 22 ambient.

20 is considered comfy. This is temperature which your bodys production and the ambient is relatively balanced, which is why a lot of HVAC systems are designed to operate at this temperature.
Anything greatly above this (25+) means your body has to compensate and as such you will sweat.

A constant 37 around the world would mean a lot of problems. Not everyones body can adjust that well. For me that would be very uncomfortable.

From a few degrees below 37 to anything above, our body loses the ability to properly regulate itself. Although in short bursts it can do so, prolonged exposure to such temperatures means your body can no longer cool itself adequately without assistance.

 

[zorro]

Thanks a lot! That cleared my doubt