Firefighters are predisposed to dehydration by the very nature of what they do. Exposure to extreme heat while wearing heavy protective clothing can easily result in the loss of a liter of fluid through sweat losses in 20 minutes or less of strenuous firefighting activity. Risks are compounded by the fact that firefighters may report for duty in an already-dehydrated state. An investigation carried out in 2007 by the Orange County Fire Authority found that of a population of 126 professional firefighters, 91% were dehydrated (as defined by National Athletic Trainers Association standards) prior to commencement of the study. The researchers also noted that firefighters are usually unaware of how much fluid they may lose during an incident or the amount of fluid required to adequately re-hydrate.
The progressive dehydration that may result can have critical, detrimental effects. Heat cramps are the mildest form of heat/dehydration-related illness that commonly affects firefighters, characterized by painful muscle spasms - usually in the abdomen, hamstrings, or calves. Such cramps may come on very suddenly and can be excruciating. A more serious heat illness affecting firefighters is heat stroke, brought on by severe dehydration and resulting in a complete breakdown of the body's ability to regulate core temperature. Sweating stops and confusion, delirium, loss of consciousness, convulsions or seizures may follow. If left untreated, heat stroke can lead to coma or death.
In light of this, there is significant interest within the firefighting community in the availability of a practical, non-invasive, real-time, hydration measurement and monitoring device for routine field deployment. Indeed, a substantial part of Cantimer's development effort and clinical study work has been funded through a contract from the Technical Support Working Group, specifically geared towards the development of devices for incident-scene assessment of dehydration in firefighters.