The Navy SEAL Physical Fitness Guide 191
sure it is a cold environment when the ambient temperature is below 15° F and the wind
speed is greater than 25 mph. Such environments pose potential dangers to those exposed
for any length of time.
Factors that Compromise Adaptations to Cold
" Inadequate Energy Intake: Reduces the ability to
generate “metabolic” heat." Injury or Poor Physical Conditioning: Inhibits ability to generate
heat through vigorous exercise." Dehydration: Places greater demands on the heart and speeds up fatigue.
" Low Percentage of Body Fat: Subcutaneous fat has insulating proper-
ties which help protect against heat loss. This is a concern for SEALs, who
usually have low body fat." Excessive Sweating: Dress appropriately using a layering system
and ventilate as necessary to avoid excessive sweating. Sweat will
destroy the insulating qualities of cold weather clothing and cause
unwanted cooling by evaporation and freezing." Alcohol: Increases peripheral blood flow which promotes heat loss and
causes core temperature to fall more rapidly.Acclimation to the Cold
Unlike acclimation to hot environments, there is little evidence to suggest that in
humans, there is a significant physiologic adaptation to the cold. There is evidence to
suggest that hands which are exposed to the cold for 30 minutes per day for three weeks
will receive more blood flow and gradually become more “functional”. However, there is
greater heat loss through hands conditioned in this manner.
Cold Injuries
The spectrum of cold injuries experienced in the SEAL community is broad, but all
can be avoided by wearing appropriate clothing and paying attention for signs and
symptoms of cold injuries.