Page 78 - Journal of Special Operations Medicine - Summer 2015

higher total exertion. The fact that the Nonfinishers had one hand and physical and cognitive impairment on the
significantly higher leukocyte counts despite experienc- other have a negative amplifying effect on each other.
ing less total exertion suggests that this might not have This means that hypothermia increases the likelihood of
been caused by the total level of exertion, but by an ex- soldiers dropping out because of impairment, while the
ertion peak. In most studies we looked at, blood param- reverse conclusion is that there is an increased risk of ex-
eters were determined at the end of a period of exertion. hausted soldiers developing hypothermia. In our group,
No studies were identified where the focus was on Non- this was evidenced by the significantly lower body tem-
finishers. However, there are studies that show physical peratures among the Nonfinishers. It is thus important
exertion above the anaerobic threshold is accompanied to carry out consistent and thorough hypothermia pro-
by more severe leukocytosis and immune modulation phylaxis from the very start of the exercise onwards.
than physical exertion below the anaerobic threshold.
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The results of our measurements of the total leukocyte As a rule, the occurrence of thermoregulatory dysfunc-
count, therefore, suggest a state of acute excessive stress tions depends strongly on the climatic conditions. Dur-
in the Nonfinishers. It is thus plausible that measuring a ing 1-day mass sporting events under similar climatic
soldier’s leukocyte count at the time of dropping out of conditions, hypothermia requiring treatment was de-
the exercise may help differentiate whether quitting the tected in 1.4% of all participants. This frequency cor-
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exercise would be due to total systemic fatigue or any of responding to that measured in our group.
many other reasons.
Medical Reasons for Soldiers Not Finishing
Studies of the immune response during Ironman triath- the Exercise
lons and 24-hour races showed CRP elevations up to A total of six participants did not finish the exercise for
levels of 3.9mg/dL and leukocytosis up to a mean level medical reasons. There are few data on the types of in-
of 20G/L. 20,21 The levels we measured are below those juries that are sustained and medical conditions that de-
described in these studies. velop during military exercises. In Naval Special Warfare
training, the frequency at which injuries are sustained in
Temperature basic training is up to 30% per month, which, after the
The temperature screening we carried out did not pro- adjustment of the person-days, corresponds more or less
duce any indication of conditions or deficiencies induced to the frequency observed in our study. The aptitude
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by hyperthermia. In particular, there was no indication exercise described in this study can be best compared
of exertional heat stroke that was either clinical or based to civilian outdoor competitions. During these events,
on temperature measurements. However, the accuracy up to 2% of the participants require medical assistance,
of tympanic temperature measurement is a controversial which corresponds to a rate of 10% for a 5-day event
issue. In general, the tympanic temperature measured and approximately to the injury rates we observed in
25
without the influence of cold water and at moder- our study. 29
ate ambient temperatures (between 12°C [53.6°F] and
34°C [93.2]) differs from the body’s core temperature by Injuries sustained during outdoor, adventure, and wil-
0.6°C (33°F) to 1.7°C (35°F). 25,26 On the whole, tym- derness activities and competitions mostly come in the
panic temperature measurement is fast and uncompli- form of contusions, sprains, and skin lesions, just as
cated, and patients are significantly more willing to have we have seen in our setting. 29,30 In contrast, fractures
their temperature taken using this method rather than and dislocations are less common and all the injuries
the more accurate rectal temperature measurement. The can generally be classified as being less severe. 29–31 Ap-
tympanic temperature measurement is sufficiently accu- proximately 20% of the cases involve exacerbated old
rate for general data collection, such as encountered in injuries, as we saw in one Nonfinisher. This emphasizes
our setting. 25 the importance of participants undergoing a thorough
medical examination before taking part in such an
Under the climatic conditions that prevailed during our event. The most common disorders are gastrointestinal
30
observation period, mild hypothermic body temperature complaints, infections, and acute respiratory diseases. In
shifts (32°C [89.6°F] to 35°C [95°F]) were more fre- this study, we observed only one case of vomiting. The
30
quent in the Nonfinisher group. One soldier showed cor- types of injuries sustained and conditions developed by
responding symptoms (at 34.6°C [94.3°F]): he felt very our group, and their frequency and severity were com-
cold and was shivering, and was treated with hot drinks parable to those seen at civilian events.
and optimization of insulation. A decrease in the core
body temperature is generally associated with physical Pass or Fail
impairment. 10,11 Physical exhaustion, sleep deprivation, Of the 29 soldiers who did not finish the exercise, seven
and a negative energy balance also foster the develop- dropped out of their own accord and 14 were with-
ment of hypothermia. Therefore, hypothermia on the drawn by the team leaders because they were slowing
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68 Journal of Special Operations Medicine Volume 15, Edition 2/Summer 2015