Cold injury, as it involves a military population, follows accepted epidemiologic
principles. A specific agent is present and a variety of environmental and host factors
influence the incidence, prevalence, type, and severity of the injury. These factors
combine in the total causation of cold injury, but the influence of each may vary in
different situations. Careful evaluation of these factors and their relative effects serves
to guide preventive and control activities.
a. The Agent. Cold is the specific agent in cold injury and is the immediate
cause of tissue damage. If, however, the effect of cold is considered the loss of body
heat, a relationship between heat conduction and heat production is seen and the ways
in which various host and environmental factors modify cold injury become clearer.
Therefore, the effect of cold cannot be evaluated by ambient (air) temperature alone.
b. Weather. Weather is a predominant influence in causing cold injury. Factors
that modify the rate of body heat loss are:
Low (freezing) temperatures favor frostbite whereas higher temperatures, together with
ground moisture, are usually associated with other cold injuries. Wind accelerates the
loss of body heat under both wet and dry conditions. The cooling effect of the wind
(wind chill) is discussed in paragraph 4-3.
c. Type of Combat Action. The incidence of cold injury varies greatly
according to type of combat action.
Units in reserve or in rest areas have few cases.
When units have holding missions or they are on static defense,
exposure is greater, and a moderate increase in incidence is expected.
When units are on active defense or offense, a marked increase in cold
injuries usually occurs.
Factors, which contribute to increasing the risk of cold injury, include:
-- Immobility under fire.
-- Prolonged exposure to the weather.
-- Lack of opportunity to re-warm and change clothing or carry out
personal hygiene measures.