It's too hot :(

asim18 said:
Umm.. Clearly you don't understand how general heat transfer and/or bodily thermoregulation works. How will it "only act on capillaries"? You think your capillaries are heat insulated from the rest of your body?

Your body is a connected mass. You cant cool only core vessels or only peripheral vessels because when you cool one, the other will automatically cool due to the nature of heat transfer in a mass.
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It's quite simple really, if you place a limb in it's entirety in a cold enclosure then according to simple laws of thermodynamics heat will be removed from the whole limb. Mass vasoconstriction in the relevant arteries and veins (they lack the necessary muscle wall to do this anyway) will not happen to the extent that it would impede passage of blood. Therefore, the blood is cooled and distributed around the body to cool the body.

However, if one just runs their hands under a hold tap you provoke a localised response where the nerves detect a temperature decrease and you get localised vasoconstriction (because arterioles and capillaries are designed to do this). Therefore, the passage of cooled blood doesn't occur in any meaningful way because the blood isn't transferred to the periphery to get cooled and transferred into the main vascular system to go around the body.

That is why people are medically cooled eg intensive care the goal is to centrally cooled. Peripheral cooling doesn't always work and sometimes will make matters worse for the very reasons I have given. More exactly because unlike your assertion the vascular system has the ability to direct blood flow and prevent blood flow all over the body. This is where you develop and create the total peripheral resistance that creates your blood pressure - the very pressure that drives the ability of the blood to move around the body. Note that the mechanisms that drive someone who is "hot" and someone who has a "fever" are different.

So how's the umm you clearly don't understand going now asim?
 
Perfectly clear sky apart from a huge cloud in the distance. It keep flashing orange all over, so looks like a storm is coming. I'll be outside when it does as this heat is killing me right now. :p
 
Naff all here in Stafford. Room is about 28* as its right next to the loft which makes the wall act like a radiator.
 
ICEx21 said:
I was sweating like a peadophile in a nursery but then one click on the remote and the air conditioner is on...unfortunately I can't programme it and unless someone wakes up in the middle of the night it's like the antarctic in here.
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Lol :D

Like a bloody Sauna right now in my room,Windows wide open..fan blasting right next to me..50c CPU temps,78c GPU temps.. :D
 
Xordium said:
It's quite simple really, if you place a limb in it's entirety in a cold enclosure then according to simple laws of thermodynamics heat will be removed from the whole limb. Mass vasoconstriction in the relevant arteries and veins (they lack the necessary muscle wall to do this anyway) will not happen to the extent that it would impede passage of blood. Therefore, the blood is cooled and distributed around the body to cool the body.

However, if one just runs their hands under a hold tap you provoke a localised response where the nerves detect a temperature decrease and you get localised vasoconstriction (because arterioles and capillaries are designed to do this). Therefore, the passage of cooled blood doesn't occur in any meaningful way because the blood isn't transferred to the periphery to get cooled and transferred into the main vascular system to go around the body.

That is why people are medically cooled eg intensive care the goal is to centrally cooled. Peripheral cooling doesn't always work and sometimes will make matters worse for the very reasons I have given. More exactly because unlike your assertion the vascular system has the ability to direct blood flow and prevent blood flow all over the body. This is where you develop and create the total peripheral resistance that creates your blood pressure - the very pressure that drives the ability of the blood to move around the body. Note that the mechanisms that drive someone who is "hot" and someone who has a "fever" are different.

So how's the umm you clearly don't understand going now asim?
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Yes I know about vasoconstriction, it has nothing to do with putting your hand under water to cool your body:

1) When you put your hand under cold water, the water is taking heat energy from your hand and making it go down the drain.

2) You have now removed a lot of heat energy from your hand and it's is now colder compared to your body.

3) You body wants to remain in a state of thermal homoeostasis. (Just like temperature equalization in matter.)

4) To bring your cold hand into thermal equilibrium with the rest of your body, Guess where that heat will come from?.

Yep, the rest of your body.

If what you're saying is true, put your hand in a bucket of ice then remove and check the surface temperature of your finger...

If your finger warms up gradually, you are wrong, if your finger stays cool forever, you are right and I will eat my hat.
 
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