Re: How come when your hand becomes so cold that it feels like it's hot?

There are a couple of  reasons that I can think of that would make your 
hand feel hot when it is cold.

First a little background. Your skin has two types of temperature 
receptors. Receptors are parts of nerve cells that send signals to let the 
brain and spinal cord know what is happening. The cold receptors tell your 
spinal cord that the skin is cold and the warm ones the skin is warm.

When the skin temperature gets really cold, the cold receptors send their 
signals back to the spinal cord (which in turn informs the brain). 
However, the warm receptors might start sending their signals back when it 
gets REAL cold too. This might make it feel like the skin is warm or even 
hot. In addition, there are also pain receptors. If these receptors are 
also activiated, this might trick the spinal cord into thinking that it is 
hot rather than cold. 

In addition, when your skin is cold, if something that is cold, but warmer than 
your skin, comes in contact with your skin, it will feel warm because it 
is warmer than your skin. For example, it your skin is 40 degrees F, and 
something that is 50 degrees F comes in contact with your skin, even 
though the 50 degree thing is cold, it is warmer than the skin and would 
feel warm. SO when your skin is cold, if something warmer contact with 
your skin, it might make your skin feel warm.