Page 72 - Journal of Special Operations Medicine - Summer 2016

exercise in either normal or hot, humid conditions, ulti-
mately impairing cognitive ability. Additionally, when a
12
troop member suffers from fatigue because of a physical
or cognitive heat-related illness, an estimated four mem-
bers of the squadron are needed to carry him/her any dis- Figure 1 Arctic Ease .
®
tance. Therefore, the prevention of heat illness among
9
military troop members seems prudent in ameliorating
battlefield mishaps and improving field performance.
Cooling devices have been introduced to help reduce
the occurrence of heat illness. Various cooling devices
are often applied to the head and neck regions based
on the concept that brain temperature can be controlled
through active cooling of that region. 10,12–14 Local cooling
of the carotid arteries during high-intensity exercise has
been found to attenuate increasing brain temperatures, Figure 2 Moisture wicking
reduce core temperatures, and improve perceptions of shirt with inserts.
physical efforts. Active cooling of the neck enhances the
12
vasodilation response of the carotid arteries, effectively
cooling the cerebral vessels. 2,14 However, these cooling
devices connected to a core-cooling vest are not strategi-
cally placed over the right or left common carotid artery.

Neck-cooling collars, cooling bandanas, cooling vests,
and clothing containing cooling microgels may contrib-
ute to enhanced work capacity. However, these cooling 4% Spandex. Pockets of the same material were created
devices may be bulky and frequently require ice or gels, to fully encapsulate the lightweight cryotherapy pad.
which are impractical for many troops who must carry The cooling medium is flame resistant to 815°C, add-
all of their gear for long distances during SUSOPS. Tra- ing to the garment’s capabilities of meeting Air Force re-
ditional cooling treatments (such as immediate hydra- quirements for flame resistance. The shirt weighs 203g,
tion or placing overheated individuals in a cool room) for a total of 471g with the cooling insert.
remove troops suffering from heat illness from their
relevant military duties, which places greater physical Subjects
demands on other troop members. Those may not be Twelve healthy, active-duty, male military members be-
options in some circumstances. Clearly, there is a need tween the ages of 19 and 30 years were recruited for
for effective, lightweight, portable methods of cooling participation in this study (mean values: age, 25.42 ±
that do not require a power source during SUSOPS. 2.84 years; height, 178.9 ± 7.92cm; weight, 78.25 ±
9.61kg; maximal oxygen uptake, 57.96 ± 1.96 mL/
The moisture wicking shirt with Arctic Ease cryo- kg/min; body fat, 10% ± 0.03%). Each provided writ-
®
therapy inserts (Gawi Healthcare, http://arcticeasewrap ten informed consent in accordance with the Air Force
.com) could provide sustained cooling effects, would Research Laboratory Institutional Review Board. Eli-
not necessarily add weight to the backpack, would gibility for study participation was determined during
not require maintenance, and could be used by a large a physical screening evaluation on the first visit. Body
number of SOF or military personnel working in hot, composition was assessed using a three-site skinfold
humid environments. Because heat-related illness is a measurement of the chest, abdomen, and thigh. Aero-
15
critical factor for military personnel operating in high- bic fitness was assessed using a single-stage submaximal
heat environments and can alter judgment and physical treadmill walking test. Subjects ranking in the top 80th
16
performance, this study was conducted to determine the percentile for aerobic fitness and top 60th percentile
effects of this novel cooling shirt (Figures 1 and 2) on for body composition, according to American College
core body temperature during high-intensity physical of Sports Medicine normative data, were eligible for
17
activity in a laboratory setting. study entrance (Table 1).

Materials and Methods Experimental Protocol
Subjects meeting the inclusion criteria returned to the
This cooling garment is a custom-designed shirt contain- laboratory for four additional testing sessions, each sep-
ing 44% Pima cotton micro model, 8% polyester, and arated by a 72-hour recovery period. For each testing

58 Journal of Special Operations Medicine Volume 16, Edition 2/Summer 2016