Military clothing and protective materiel: protection at the limits of physiological regulation
Contemporary military environments almost invariably require the use of personal protective clothing and equipment, and the burden accompanying its use can sometimes challenge the integrated regulation of critical physiological variables, pushing some individuals to the limits of regulation. Indeed, it is not uncommon for work to be prematurely terminated due to cardiovascular insufficiency. In such states, operational capability is reduced. In this Chapter, four topics will be addressed, including the impact of battle-dress uniforms, ballistic protection, undergarment moisture management, and chemical and biological protection. The principal emphasis is upon thermal and cardiovascular regulation in the person-clothing-environment system. For battle-dress uniforms, body heat storage is modelled using thermodynamics algorithms, with a three-dimensional summary presented to identify combinations of work rates and thermal exposures that yield positive heat storage. When ballistic protection is considered, one must evaluate both the impact of the added mass and the impediment it presents for dry and evaporative heat exchanges. Various moisture management practices are being marketed to address these matters. However, evidence will be presented that these do not offer measurable thermoregulatory or perceptual benefits when used beneath battle dress and ballistic protection in operational simulations. Finally, the most stressful scenario relates to protecting individuals from chemical, biological and radiological challenges. Indeed, working in such encapsulating ensembles can only be tolerated for short durations without supplementary cooling.