Be Careful of the Heat

You've got your Heat Stroke and your Heat Exhaustion and they have different symptoms.  According to The Gale Encyclopedia of Medicine:

Heat Stroke;

   Hot, dry skin

   Constricted pupils!

   Body temperature in the very high neighborhood

Heat Exhaustion;

   Clammy skin

   Dilated pupils!

   Normal to low body temperature

How can the same condition (heat) cause completely contrasting sets of symptoms?  I'm stumped!  But even I can tell you to keep your perfectly normal pupils peeled for the nasty effects of 97 degree weather.  Yikes.

Source: The Gale Encyclopedia of Medicine.