d. Clothing. In warfare, where exposure to cold may be prolonged, adequate
clothing properly worn is essential to welfare and survival. Clothing for cold weather
combat has been designed to be worn as an assembly for protection of the head, torso,
and extremities. Failure to wear the total assembly and inadequate supplies of proper
sizes of clothing are important factors in cold injury. The assembly depends upon the
layering principle to conserve body heat. Loose layers of clothing with air space
between them, under an outer wind and water-resistant garment, provide maximum
protection. It is flexible in that inner layers may be removed for comfort and efficiency to
minimize perspiration in higher ambient temperatures or during strenuous physical
exertion. Clothing wet by perspiration loses much of its insulating value, and care must
be taken to prevent perspiration from accumulating in the clothing. Moisture against the
skin causes a very rapid decrease in temperature of the tissue and can lead to frostbite
or hypothermia. In all forms of cold injury, prevention of loss of body heat is important.
All articles of clothing must be loose, to avoid constriction and tightness. Clothing must
be kept free of grease and dirt.
a. Age. Within the usual age range of combat personnel, age is not significant.
b. Rank. Trench foot and frostbite have a high selectivity for the frontline
riflemen, and predominantly those of the lower ranks. The decreased incidence of cold
injury among higher ranks is the reflection of a combination of factors, such as lesser
degree of exposure, more experience, and greater receptivity to training.
c. Previous Cold Injury. A previous episode of cold injury definitely increases
the individual's risk of subsequent cold injury, not necessarily involving the part
previously injured. However, minor degrees of superficial cold injury, when completely
healed, probably do not predispose to subsequent injury sufficiently to require profiling
or other restriction on assignment.
d. Fatigue. Fatigue is a factor contributory to cold injury. Mental weariness
may cause apathy leading to neglect of acts vital to survival. This occurs more
frequently in personnel who have been in combat for 30 days or more without rest.
Frequent rotation of troops from active combat duty for even short periods lessens the
influence of the fatigue factor.
e. Concomitant Injury. Experience has shown that injuries resulting in
significant blood loss or shock reduce effective blood flow to extremities and predispose
to cold injury.