Lets just say that you are ship-wrecked or your aeroplane had crashed. Would you rather be in some kind of Desert where you would die from heat and dehydration, or would you prefer to be frozen in some kind of Icy wasteland?
When you shiver from coldness that is actually your body trying to warm up, but to do this it is shutting off vital parts of your body. After a while your organs start to shut down; your lungs, liver kydneys and others, and then finally your heart. Thats how you die from coldness. Heat on the other hand is dehydration in which your body drastically needs water and can cause you to go insane and start hallucinating. Then you Die.
Personally I would prefer to freeze to death. My reason is because your body will eventually become numb and you could just lie their and wait for all your organs to shut down.
Dying from Heat I think would be horrible. It seems more slower and laying there sweating in the summer is bad enough for me.
But I'm not 100% sure. I have always found this quistion hard to answer due to the fact that both these sourses are exact opposites and are bad in their own ways. What do you say?