Effectiveness of heat blankets in preventing hyperthermia in Dutch military personnel

In an extremely cold environment, Dutch soldier have to be able to remain safe
for four hours when they do not have the possibility to move themselves. To do
so, they carry heat blankets along in their equipment. To make an informed
decision on which heat blankets are suitable for this purpose, information is
needed on the effectiveness of three commonly used heat blankets

The objective of the study is to determine the effectiveness of three types of
heat blankets in reducing the cooling rate of the human body in arctic
conditions

The study has a within subject design with repeated measurements. Each subject
will conduct three experimental sessions and in each session another heat
blanket will be used.

The intervention consists of three distinct configurations of heat blankets.
Configuration A is the Blizzard Survival Blanket. Configuration B is the
Blizzard Survival Blanket plus four Blizzard A5 heating pads. Configuration C
is the Blizzard Survival Blanket plus the Ready-Heat full body temperature
management blanket.

The subjects will visit the climate testing room in Woensdrecht 3 times a week.
During these visits they will be exposed to a temperature of -30°C for 4 hours
- wrapped in winter clothing and a heat/insulation blanket. During this period,
the body temperature will be continuously measured with a thermo capsule, skin
temperature will be measured with small buttons and heart rate will be measured
with a monitor worn around the upper arm. The subjects also give a score for
thermal sensation and thermal comfort every half hour. The risks when using the
heat/insulation blankets are minimal as they are CE-certified products that are
used in accordance with the regulations. The risk of hypothermia is minimized
by the continuous monitoring of body temperature. When a subject reaches a body
temperature of * 35.0°C (the limit of mild hypothermia), the subject is taken
out of the cold and warmed up with hot drinks. The risk of frostbite injury is
minimized by thoroughly covering the skin with clothing. The main risk
associated with the use of the measuring devices is the oral ingestion of the
telemetric temperature pill. This is not a problem for people without
gastrointestinal disorders and the pill leaves the body again naturally within
12-36 hours. Measures are taken to ensure that the subjects do not undergo an
MRI scan while they still have the telemetric pill within their body. This is
done by emphasizing the danger of this and by making it mandatory to wear a
plastic bracelet stating that the subject has a telemetric pill in his/her
body. In summary, the risks of participating in this study are very minimal.
The subjects do not receive any compensation for participating in the study.
They can experience how their body reacts to extreme cold, which can be useful
in the future. They also contribute to obtaining well-functioning equipment for
arctic training and deployment, which benefits the entire organization.