Mary Phyl raises an interesting point and this week's "30 Days to a More Powerful Vocabulary" word, Hyponatremia. This is a condition caused by a shortage of Beer Nuts, and accompanying fluid intake.
Seriously, this is a shortage of sodium, which can be worsened by dramatic increases in water consumption, which further dilutes the sodium left in the system. Consumption of non-steroidal anti-inflammatory drugs such as aspirin, naproxyn or ibuprofen; diuretics, such as my hourly can of Starbuck's Expresso Double Shot (why don't they make those in 24 oz. size??) or tylenol can increase the potential severity of this condition by messing with renal function efficiency. Not surprising that a Canyon discussion group would explore this topic.
Salt tablets are no longer popular. However doing long term exercise in hot weather, such as climbing up the South Kaibab, will deplete sodium and increase the intake of fluid, further diluting the remaining sodium in the system, resulting in a condition similar to when Mike gave me Last Rites in Sycamore Canyon a couple years ago. ( Who woulda thought he carried those purple vestments in his daypack? I survived, and he had to give back the stuff he pilfered out of my pack

) Gatorade just doesn't do it, you need more sodium than that.
There's a good discussion at
http://www.rice.edu/~jenky/sports/salt.html and at
http://www.rice.edu/~jenky/sports/hyponatremia.html regarding this condition. -R