Page 76 - Journal of Special Operations Medicine - Spring 2014

tells you that the training leading up to combat was Operational Stressors on Endogenous
much harder than the actual combat, then you know Hormones, Body Composition, and Sleep
you have conditioned a Soldier correctly through tough The physical and cognitive ability of Special Opera-
6
and realistic training.” However, due to the nature and tors to endure stressful combat situations rely heavily
location of some SO missions and deployments, these on their intense physical training, which typically mir-
Special Operators may endure several days to weeks of rors a multitude of very similar scenarios they will en-
operational stressors such as sleep deprivation, caloric counter on the battlefield. Sustained military operations
deficit, high-energy expenditure, and extreme environ- (SUSOPS) can negatively affect Special Operators due to
mental conditions ranging from tropical climates to the (1) physical and cognitive fatigue, (2) sleep deprivation,
subarctic/arctic regions and varying terrain (e.g., snow, (3) high caloric expenditures, (4) diminished appetites,
mud, sand) and altitudes. 7–9
(5) energy deficits, (6) heavy combat loads (sometimes
exceeding 50kg), and (7) environmental extremes. 7,9
According to Kim and Diamond, stress is a condition As a result of Special Operators enduring these opera-
in which a person (i.e., Special Operator) experiences tional stressors for sustained and frequent periods of
a heightened excitable response due to an aversive sit- time, levels of circulating anabolic hormones decrease,
uation. The magnitude of the stress response will be while catabolic hormones increase. Additionally, skel-
10
greater if the stressor is perceived as uncontrollable. etal muscle atrophy and bone loss have been reported,
Decrements in physical performance and increased as well as an increase in musculoskeletal injuries (e.g.,
risk of injury may result due to operational and physi- lower extremity stress fractures, ankle sprains, anterior
ological stressors, thereby compromising mission effec- knee pain, iliotibial band syndrome) and a decrease in
tiveness and the lives of Special Operators. Therefore, physical/military performance, all of which may com-
commanders may assess certain physical stressors by promise mission success and the lives of Operators. 7,11–15
administering simple field tests. Suggested specific Whether training to become a Special Operator or de-
countermeasures may then be used to better assess Op- ployed for SUSOPS missions, Special Operators must
erators’ risk of musculoskeletal injuries and enhance be able to endure multiple operational stressors (e.g.,
physical performance. A 2011 review by Henning and negative energy balance, sleep deprivation, environmen-
colleagues highlighted the current literature of physio- tal extremes) in addition to physiological stressors (e.g.,
logical decrements during sustained military operational endocrine changes, muscle atrophy, weight loss) related
stress. Henning et al. reviewed the effects of this stress to intense training or missions.
7
on physical and military performance, endocrine status,
skeletal muscle, and bone injuries. They suggested coun- For example, the U.S. Army Ranger School is a leader-
termeasures to be used by commanders to plan missions ship course for elite Soldiers who upon graduating can
accordingly. This group of investigators aims to expand become part of Special Operations (i.e., 75th Ranger
on the review of this topic and suggest additional coun- Regiment) or return to their units to lead Soldiers in
termeasures that may reduce injury rates, reduce recov- combat. Soldiers must endure a grueling 61-day course,
ery time between missions, and improve overall human which demands physical and mental toughness in heav-
performance.
ily wooded areas, desert (eliminated in 1995, replaced
with urban combat training), mountainous terrain, and
Nutrient intake, personal fitness, environmental condi- swamp-like conditions. Nindl et al. studied the physio-
tions, and equipment worn and carried by Operators logical consequences of Ranger School (a 1992 class) on
during training and critical missions are all important strength, power, body composition, and somatotrophic
factors for commanders or team leaders to consider. hormones. Ranger School is designed to be high stress.
16
A key concern during military operations is the ergo- Along with the challenge of adapting to environmen-
nomic constraints posed by personal protective equip- tal extremes, Ranger students experience caloric deficits
ment (PPE) that may limit a Special Operator’s range ranging from 1,000 to 4,000 kilocalories (kcals)/day
of motion and induce heat stress. This may result in a during 7–10 days of underfeeding per phase, sleep an
reduction in physical performance. Ideally, PPE should average of 3.6 h/day, and expend more energy than con-
provide adequate protection to operational threats sumed for the majority of the 8-week course. 16
while not inhibiting an individual’s ability to perform
required tasks. Aside from the PPE worn by Special Op- These conditions are analogous with reports from
erators, their missions often require them to carry heavy other military Special Operators (i.e., U.S. Army Rang-
1
loads. Carrying heavy loads during missions in adverse ers, Special Forces, etc.) in which caloric deficits have
environments increases the amount of energy required ranged from 2,500 to 4,500kcal/day during operational
to successfully complete any physical task, thus result- situations. As a result of 61 days of exposure to these
16
ing in overall decrements in physical performance.
stressors, circulating concentrations of total testosterone

68 Journal of Special Operations Medicine Volume 14, Edition 1/Spring 2014