Disorders of fluid and electrolyte balance in the U.S. military result in at least 125 hospitalizations, two lost duty days per event, and 9,300 ambulatory hospital visits per year (60% hyponatremia, 40% dehydration) (Carter et al., 2005; DoD, 2008). Diarrhea is a major infectious disease threat which requires aggressive i.v. fluid replacement in 30% of U.S. troops deployed to Iraq or Afghanistan (Brown et al., 2009). It is also important to recognize that the management and outcome of the 662 severe or penetrating traumatic brain injuries (TBI) reported for the military in 2009 (DoD, 2010) may be hindered by dehydration (Clifton et al., 2002). Fluid and electrolyte imbalances also contribute to heat illness (Carter et al., 2005) and can substantially impair combat fighting effectiveness (Dupont, 2003).