residual limbs are covered with a prosthesis, both of which
may decrease the ability to dissipate heat. Hindrance to
any thermoregulatory mechanisms may increase the risk of
heat injuries.
2
To date, there is only one published pilot study compar-
ing the core temperatures of service members with and with-
out amputations leaving open to discussion whether service
members with amputations are more susceptible to heat inju-
ries than their counterparts without amputations.
9
The pri-
mary objective of this study was to determine if individuals
with amputations were more predisposed to heat illnesses than
individuals without amputations by comparing core tempera-
ture during a prolonged endurance event. We hypothesized
that individuals with amputations would have higher core
temperatures than individuals without amputations. Second-
ary objectives included determining how BSA and hydra-
tion status affected core temperature in individuals with
and without amputations during a prolonged exercise event.
We hypothesized that decreased BSA would be directly cor-
related with higher core temperature while hydration status
would be inversely correlated.
METHODS
The current study is a case
–control investigation to test
whether individuals with amputation are at increased risk
of heat injury while performing duties typical to military
service, this study was conducted during the Bataan Memo-
rial Death March (BMDM), a 26.2-mile road march in New
Mexico, on March 27, 2011. The event mimics extended
marching frequently performed by many operational mili-
tary forces.
Twenty participants from a convenience sample of
service members planning to participate in the event
volunteered for this study: 10 with amputations and 10 with-
out amputations served as a control group. The participants
with limb loss included 7 participants with a unilateral trans-
tibial (below the knee) limb loss, 1 participant with a unilat-
eral transfemoral (above the knee) limb loss, 1 participant
with unilateral transradial limb loss, and 1 participant with
unilateral transhumeral limb loss. The range in time since
amputation was 6.97 to 39.87 months (mean 15.10 months).
All participants were recruited from teams at Walter Reed
Army Medical Center, Washington, DC, and Joint Base San
Antonio, Texas who were trained and had already registered
for the event. Participants were contacted by the study team
during training sessions for the event or by word of mouth
upon referral from the medical staff. The Walter Reed Army
Medical Center Institutional Review Board approved the pro-
tocol and all participants provided written, informed consent.
Research team members met with participants at their respec-
tive sites before the pre-event data collection session in
order to explain the study and study-related risks.
All participants were active duty or retired service mem-
bers. Participants with amputations were required to have
had at least 6 months of prosthesis usage before the event
and a physician cleared all participants who were still under-
going medical treatment. Participants were excluded from
the study if they had previous heat injuries, nontraumatic
amputations, neurological, cardiovascular, pulmonary, ortho-
pedic, or other conditions or medications that would contra-
indicate completion of a 26.2-mile march or swallowing an
ingestible sensor.
Data collected before the event included height, weight,
body composition, body mass index (BMI), and BSA. Pre-
event weight was collected just before the start. During the
event, core temperature was monitored using ingestible core
temperature sensors. Following completion of the event,
event duration was recorded and postevent weight and urine
specimen were collected. All participants wore comfortable
attire and shoes or boots during the event.
Body composition and background information were
collected within 4 weeks of the event. Background infor-
mation included age, gender, and the date and level of any
amputation. Body weight was measured on a calibrated
digital scale to the nearest 0.1 kg. Participants reported their
height from their last preinjury physical
fitness test. This is
an of
ficial military measurement conducted according to pre-
cise standards.
10
BMI was calculated using standard calculations (kg/m
2
).
Adjusted weight was used for participants with amputations.
Adjusted body weight was calculated as current body weight/
(1
− P), where P is the proportion of total body weight rep-
resented by the missing limb or limbs.
11
BSA was calculated using the Mosteller (1987) for-
mula, the preferred method in clinical medicine for deter-
mining BSA:
12
Without amputations
: BSA m
2
À Á
¼ H cm
½ Â W kg
½ =3; 600
ð
Þ
0
:5
With amputations
: BSA m
2
À Á
¼ BSA À BSA
½
 % BSA part
½
ð
Þ
Percent (%) BSA part re
flects the level of amputation of the
missing limb or limbs.
13
Calculated BSA for participants
with amputations used adjusted weight and excluded the area
covered by the prosthesis liner.
Body composition was measured by dual-energy X-ray
absorptiometry (DXA Windows XP version QDR software,
Hologic, Discovery-Wi, Bedford, Massachusetts). Data col-
lected include lean mass, fat mass, and body fat percentage.
Participants were scanned in minimal clothing with prosthe-
ses, jewelry, and metal objects removed.
Participants were weighed on site using a calibrated digi-
tal scale before and after the event to account for
fluid loss.
Participants consumed food and beverages ad libitum during
the race. Urine samples were taken immediately after par-
ticipants completed the BMDM to assess hydration status.
Urine-speci
fic gravity (USG) was assessed using a calibrated
hand
–held refractometer (model HR-200 ATC, AFAB Enter-
prises, Eustis, Florida).
Calibrated temperature sensors (CoreTemp, HQ Inc,
Palmetto, Florida) were distributed to the participants the
night before the event and ingested by participants the
MILITARY MEDICINE, Vol. 181, November/December Supplement 2016
62
Core Temperature in Service Members With and Without Traumatic Amputations