The use of creatine supplements in the military

Abstract

Introduction: Creatine is considered an effective nutritional ergogenic aid to enhance exercise performance. In spite of the publication of several reviews in the last decade on the topic of exercise performance/sports and creatine there is a need for an update related to the military given the lack of information in this area. The aim of this study was to critically assess original research addressing the use of creatine supplements in the military.
Methods: A search of the electronic databases PubMed and SPORTDiscus, for the following key words: military personnel, trainees, recruit, soldier, physical fitness, physical conditioning, creatine supplementation, creatine ingestion, nutritional supplements to identify surveys and randomised clinical trials from journal articles and technical reports investigating the effect of creatine supplementation on military populations.
Results: Thirty-three out of 90 articles examined the use of creatine as a dietary supplement in military
personnel. Twenty-one studies were finally selected on the basis of stated inclusion criteria for military surveys and randomised clinical trials. Most of the surveys (15/17) in the military indicate a high popularity of creatine (average 27%) among supplement users. In contrast, in most of the exercise protocols used (6/9) during randomised clinical trials creatine has produced a nonsignificant
performance-enhancing effect.
Conclusions: Creatine is one of the most widely used supplemental compounds in the military. It is not considered a doping infraction or related to any adverse health effects but its long-term usage needs further investigation.Experimental research suggests that creatine supplementation does not enhance physical performance in the military. However, limitations in creatine dosage, military fitness testing and sample group selection might have underestimated the ergogenic properties of creatine. Recent studies also indicate positive effects on various aspects of total force fitness such as cognitive-psychomotor performance, bone health, musculoskeletal damage and neuromuscular function.

Full text

The use of creatine supplements in the military
Konstantinos Havenetidis
Correspondence to
Professor Konstantinos
Havenetidis, Human
Performance-Rehabilitation
Laboratory, Faculty of Physical
& Cultural Education, Hellenic
Army Academy, Vari-Koropiou
Avenue, Vari, Attiki 16673,
Greece; khavenetidis@sse.gr
Received 22 December 2014
Revised 4 March 2015
Accepted 8 March 2015
Published Online First
29 June 2015
▸http://dx.doi.org/10.1136/
jramc-2015-000482
To cite: Havenetidis K. JR
Army Med Corps
2016;162:242–248.
ABSTRACT
Introduction Creatine is considered an effective nutri-
tional ergogenic aid to enhance exercise performance. In
spite of the publication of several reviews in the last
decade on the topic of exercise performance/sports and
creatine there is a need for an update related to the
military given the lack of information in this area. The
aim of this study was to critically assess original research
addressing the use of creatine supplements in the
military.
Methods A search of the electronic databases PubMed
and SPORTDiscus, for the following key words: military
personnel, trainees, recruit, soldier, physical fitness, phys-
ical conditioning, creatine supplementation, creatine
ingestion, nutritional supplements to identify surveys and
randomised clinical trials from journal articles and tech-
nical reports investigating the effect of creatine supple-
mentation on military populations.
Results Thirty-three out of 90 articles examined the
use of creatine as a dietary supplement in military
personnel. Twenty-one studies were finally selected on
the basis of stated inclusion criteria for military surveys
and randomised clinical trials. Most of the surveys
(15/17) in the military indicate a high popularity of creat-
ine (average 27%) among supplement users. In contrast,
in most of the exercise protocols used (6/9) during
randomised clinical trials creatine has produced a non-
significant performance-enhancing effect.
Conclusions Creatine is one of the most widely used
supplemental compounds in the military. It is not consid-
ered a doping infraction or related to any adverse
health effects but its long-term usage needs further investi-
gation. Experimental research suggests that creatine
supplementation does not enhance physical performance in
the military. However, limitations in creatine dosage,
military fitness testing and sample group selection might
have underestimated the ergogenic properties of creatine.
Recent studies also indicate positive effects on various
aspects of total force fitness such as cognitive-psychomotor
performance, bone health, musculoskeletal damage and
neuromuscular function.
INTRODUCTION
The development of sports science has occurred
alongside the development of a myriad of different
ergogenic aids aimed at lowering barriers to human
athletic performance. Currently, considerable atten-
tion is being devoted to the ergogenic properties of
the supplement creatine.
1
In the military, servicemen in a similar manner to
elite athletes, also need to maximise their physical
performance in order to meet the physically
demanding tasks they perform. During sustained
operations, many stress factors are magnified due to
sleep deprivation, incomplete exercise recovery,
extreme environmental conditions and calorific
deficit. Under these circumstances servicemen may
seek ‘miracle’substances that will boost their per-
formance, as failure to complete specific military
events for any reason (illness or injury) would not
be tolerated.
This article reviews the literature on the use of
creatine supplements in the military, addressing the
health and ethical issues involved, based on the
hypothesis that it is an ergogenic acid which can
favourably influence military exercise performance.
Creatine metabolism
Creatine is a nitrogenous organic compound found
almost exclusively (98%) in muscle and is primarily
synthesised in the liver, but also in the kidneys,
pancreas and mammary gland from essential (argin-
ine, methionine) and non-essential (glycine) amino
acids.
2
When formed, it is released into the blood-
stream and transported to muscle tissue against a
concentration gradient. The control of muscle cre-
atine concentration is regulated by liver enzymes
responsible for creatine synthesis and by creatine
and creatinine (anhydro product) levels in the
blood which regulate excretion rates
3
(Figure 1).
Under conditions where food is unavailable, the
liver can adjust its metabolism to process com-
pounds released from muscle and other tissues in
response to certain hormonal signals. An average
carnivorous diet includes 1–2 g of creatine daily
Key messages
▸Creatine has proven to be a popular, legal and
safe supplement among military personnel,
even though there is little data regarding its
long-term effects.
▸The limited experimental research in the
military indicates a non-significant
performance-enhancing effect during
short-term creatine supplementation.
▸Possible potentiating effects of creatine in the
military may be masked if guidelines related to
dosage, fitness testing and group selection are
not implemented.
▸Creatine can become a critical element in the
success of military operations requiring rapid
rehabilitation periods, high physical cognitive
performance, minimal injuries and energy
replenishment.
▸Future researchers should evaluate creatine use
during longer supplementation periods, exercise
bouts simulating various military occupational
tasks and more controlled experimental and
field studies.
242 Havenetidis K. J R Army Med Corps 2016;162:242–248. doi:10.1136/jramc-2014-000400
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which is exclusively provided by meat products such as red and
white meat, fish and molluscs; 1 kg of raw meat contains
approximately 5 g of creatine.
4
However, manipulation of daily
creatine intake through diet seems to be a complex procedure
since many factors (cooking time, type of meat, muscle site)
influence creatine values after ingestion.
5
The main function of creatine is to replenish creatine phos-
phate (CP) which is one of the limiting factors for maintaining
the high rate of energy turnover during high intensity exercise.
This function can be achieved during recovery periods where
creatine acts as an energy transporter between the unlimited
energy supplies (fat stores) and the sites where the work is pro-
duced (muscles).
3
This mechanism was the theoretical back-
ground for the suggestion that exogenous creatine could
improve CP resynthesis and eventually lead to performance
enhancement.
Exercise and creatine supplementation
In the last 20 years substantial scientific evidence has accumu-
lated which demonstrates the beneficial effect of creatine on exer-
cise performance, at least under laboratory conditions where
cycle ergometry, treadmill running and isokinetic-isometric
dynamometry were used.
6–8
Other studies conducted in more
representative environments,
910
using various sporting activities
showed that performance also improved but to a significantly
lower extent. This inconsistency in performance gain has been
attributed to differences between studies such as exercise mode,
diet, creatine dosage, number and category of participants
(responders or non-responders), methods of measurements and
statistical analysis.
Despite these issues there are some circumstances under
which any potential benefit of creatine supplementation is mag-
nified: a participant’s body mass should show an increase of
approximately 5% following the creatine loading phase, as this
increase is correlated to an increase of creatine uptake in the
muscle
11
; the recommended exercise protocol should consist of
short-term (up to 30 s) maximal-intensity exercise bouts per-
formed in repeated succession
1
and the recommended creatine
dosage should be within the range of 20–30 g/day for a 5–7-day
period (loading phase) followed by a maintenance phase of
2–5 g/day for several weeks.
12
Another recommended dosing
strategy (relative to body mass) involves 0.03–0.1 g/kg/day for a
28–40-day period.
13
The beverage should contain, in addition
to creatine, carbohydrate and/or protein for augmenting creatine
muscle retention,
12
and the recommended creatine regime,
totalling 20–30 g/day (loading phase), should comprise small
doses (5 g) (4–6 intakes/day) of creatine monohydrate
(in powder form) distributed at 2–3 h intervals or 1 g doses
(20–30 intakes/day) evenly distributed at 30-min intervals. On
each occasion (loading or maintenance phase) powder should be
well dissolved in adequate volume of warm water (300–
500 mL).
14 15
The above circumstances, in almost all cases, increase intra-
muscular creatine content by 10–20% alongside a 2–20% exer-
cise performance enhancement.
16
and the proposed mechanisms
are listed in Table 1.
METHODS
To determine potential effects of creatine supplements on
military physical performance, MEDLINE (PubMed) and
SPORTDiscus were searched for original studies involving mili-
tary populations (comprising only humans and aged above
19 years old) ingesting exogenous creatine. Search was per-
formed using the terms ‘military personnel’,‘trainees’,‘recruit’
and ‘soldier’with ‘physical fitness’,‘physical conditioning’,‘cre-
atine supplementation’,‘creatine ingestion’,‘nutritional supple-
ments’. The search for relevant articles contained only the
Table 1 The mechanism of improved exercise performance from
creatine supplementation
Mechanisms that facilitate exercise
performance
Potentiating effects on exercise
performance
Higher initial CP availability and
resynthesis
16
Greater dynamic strength and
endurance
17
Increased ATP resynthesis
12
More efficient muscle damage
attenuation
18
More efficient antioxidant activity
19
Faster and higher power production
20
Increased muscle protein kinetics
21
Accelerated muscle hypertrophy
22
Increased hormonal proliferation
22
Decreased recovery time during
anaerobic activity
23
Enhanced fatigue resistance
8
Searches were performed using the terms: ‘military personnel’,‘creatine’.
CP, creatine phosphate. Figure 2 Study selection procedure for data synthesis.
Figure 1 Creatine synthesis and excretion.
Havenetidis K. J R Army Med Corps 2016;162:242–248. doi:10.1136/jramc-2014-000400 243
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reference lists of journal articles and technical reports. All
studies (military surveys and experimental studies) were initially
examined. Afterwards, an additional inclusion criterion for mili-
tary surveys was the citation of creatine, without any other addi-
tions (such as ephedra) in the dietary supplement lists. Different
inclusion criteria were used for the experimental studies such as
minimal washout periods of 28 days or more (cross-over experi-
mental design), creatine dosage higher than 2 g/day for 4 days,
random and concealed allocation of subjects to groups, groups
of similar abilities, blinding of all subjects-supplements-test
administrators. After meeting the aforementioned inclusion cri-
teria a total number of 21 studies were included in the review
(Figure 2).
RESULTS
Data from military studies
In the military, physical fitness is emphasised because of its role
in military readiness and force health protection. Improving
physical fitness is a vigorous and time-consuming procedure
where specific exercise, nutrition and sleep guidelines need to
be followed. However, current military doctrine requires the
ability to maintain round-the-clock operations in order to
achieve mission objectives. Under these circumstances military
personnel often turn to various ‘unknown’supplements in
order to optimise performance in demanding situations. Table 2
demonstrates the high usage of creatine supplements among
various military groups.
Most of these surveys have been conducted in the US Army,
with a focus on Special Operations Forces (SOF). Several investi-
gators
24 25 27 32
who investigated the use of dietary supplements
in the US Army Rangers reported that creatine usage was high
in this military subpopulation (13–19%), while, others
31 33
reported even higher usage (26% and 46%) using participants
from various groups of SOF (Marines, Rangers). Among the six
categories used in that survey,
31
(anabolic steroids, amino acids,
thermogenics, androstenedione, creatine, protein) creatine
supplements were the second most commonly used dietary
supplement. In these studies, creatine supplements were con-
sumed by SOF at rates similar to athletic populations possibly
because SOF are also intrinsically motivated to maximise their
performance. Similar results were also presented by investiga-
tors,
26 28 30 34
who used large-scale surveys and assessed various
Table 2 Recent surveys (1999–2014) on creatine use by military personnel
Study
Subjects
Response rate (%) Usage (%)Situation Gender N
Arsenault and Kennedy
24
Army Special Forces Men 2215 99 18
McGraw et al
25
Army Rangers Men 367 NK 19
Sheppard et al
26
General Army Men and women 133 40 29
Deuster et al
27
Army Rangers Men 38 100 13
Thomasos
28
Air Force enlisted and officers Men and women 10 985 NK Rated 1st*
French
29
National Guard-Reserve Men and women 376 60 6
Jaghab
30
Army physicians Men and women 573 15 33
Ancillary 674 15 27
Johnson et al
31
Army Rangers Men 294 40 46
Lieberman et al
32
General Army Men and women 484 80 5
Army Rangers Men 768 NK 19
Special Forces Men 152 NK 16
Young and Stephens
33
Marines Men 323 65 26
Lieberman et al
34
Active-duty Army personnel Men and women 990 80 42
Boos et al
35
Deployed military personnel Men and women 1017 66 13
Boos et al
36
Deployed servicemen Men and women 87 58 34
Casey et al
37
Active-duty Army personnel Men and women 3168 NK 38
*Supplements ranked according to most often used; Usage, number of creatine users among supplement users.
NK, not known.
Table 3 Experimental studies investigating the effect of creatine supplementation on military personnel’s exercise performance
Study (design)
Subjects
Dose and duration of creatine used Exercise method BenefitPersonnel N
Ensign et al
38
(DBPP) Navy Seals 24 20 g/day for 4 days Obstacle course, 3 runs No
Bennett et al
39
(DBPP) Military personnel 19 20 g/day for 6 days then 6 g/day for 28 days March, 10 miles No
Run, 5 miles No
Pull-ups to exhaustion Yes*
Warber et al
40
(DBPP) Army soldiers 13 24 g/day for 5 days Obstacle course, 3 runs No
Bench presses, 5× reps to exhaustion Yes***
Baker-Fulco et al
41
(DBPC) Active duty Army soldiers 7 20 g/day for 7 days then 5 g/day for 7 days Static knee contractions, 2 trials to exhaustion No
*Armentano et al
42
(DBPP) Active duty Army soldiers 35 20 g/day for 7 days Push-ups, 2 min, No
Koenig et al
43
(SBPP) Recreational Athletes-Army 60 25 g/day for 5 days Static jump, 2×10 reps Yes*
*Significance level at 0.05; ***significance level at 0.001.
DBPC, double-blind, placebo, crossover; DBPP, double blind, placebo controlled, parallel group; SBPP, single blind, placebo controlled, parallel group.
244 Havenetidis K. J R Army Med Corps 2016;162:242–248. doi:10.1136/jramc-2014-000400
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non-SOF populations (Army physicians, Administrative
Officers-Technicians, Air Force enlisted and officers, active-duty
Army personnel). In these surveys creatine was administrated by
a high proportion of military personnel (27–33%) and on a
regular basis compared with other supplements.
By contrast, other studies
29 32
have shown that creatine use
was not popular (5–6%) among general Army personnel and
military National Guard-Reserve participants with Vitamin C
and calcium being the most common dietary supplements used
(13%).
Apart from US troops, Boos et al,
35
in a large observational
study of 1017 deployed British servicemen to Iraq reported that
13% of the users preferred creatine among other nutritional
supplements. The same investigators
36
highlighted the issue and
potential concerns regarding the unregulated use of dietary sup-
plements within the British military in Afghanistan; again one
of the main types of supplements used by that sample group
(n=87) was creatine (34%) surpassed only by protein. Casey
et al,
37
in a survey comprising various British Army troops
(Infantry, Parachute Regiment Units, Royal Armoured Corps,
Royal Artillery and Royal Engineers) also reported that creatine
was widely consumed (38%) among supplement users.
In one of the surveys conducted,
26
creatine users extended
the supplementation period ( from 4 weeks to 40 weeks) result-
ing in a 5–10-fold increase in the total recommended creatine
ingested. Most of the users relied on popular media such as
fitness magazines, rather than nutritionists for information on
creatine, suggesting that creatine users, in their pursuit of a per-
formance advantage often follow creatine regimens of question-
able efficacy and/or safety. Experimental research in the military
about the use of specific supplements is limited, and especially
so for creatine ingestion (Table 3).
In a study,
38
conducted in the USA, the role of creatine sup-
plements was assessed in a group of 24 Navy Seals. The
researchers measured a series of physiological parameters such
as volume of intracellular-extracellular fluid and body fat per-
centage as well as physical performance (obstacle course passing
time). Τhe results showed that the creatine group presented sig-
nificantly higher intracellular fluid volume but not extracellular
or total water volume. Warber et al,
40
tested 13 male soldiers
performing three consecutive military obstacle course runs fol-
lowed by a rifle marksmanship task on three occasions each
separated by 5 days. The same soldiers also completed a con-
trolled strength test which comprised repeated bench presses
(five sets to failure at 70% of one repetition maximum) and
answered the Profile of Mood States questionnaire during each
test session. Creatine usage (24 g/day for 5 days) significantly
improved performance during the controlled strength test by
14% but did not significantly improve military obstacle course
performance, marksmanship or mood.
By contrast, Baker-Fulco et al,
41
showed no improvement in
exercise performance following creatine ingestion. The authors
examined whether creatine supplementation improves muscle
performance in a group of seven Army recruits during exposure
to acute hypobaric hypoxia. The exercise involved submaximal
intermittent static knee contractions interspersed with maximal
voluntary contractions every minute to exhaustion after supple-
mentation with creatine. There was no effect of creatine on
maximal force, muscle endurance, or recovery in normoxia or
hypobaric hypoxia but the small number of participants may
have affected the statistical analysis. Koenig et al,
43
investigated
the effect of creatine supplements (25 g/day for 5 days) on
repeated static jump performance (two sets of 10 jumps in 60 s)
using a group of Army recruits (n=10). The authors
demonstrated that creatine supplementation significantly influ-
enced jump height after the sixth bout ( p<0.05) and prevented
the increasing pattern of fatigue that occurs in repeated jump
performance.
Despite the fact that almost all studies demonstrated no bene-
ficial effect of creatine on military exercise performance, further
scientific data are required before the military community is
fully apprised of the effects of creatine administration.
Overcoming previous limitations of small sample group and
poor study design, recent studies using non-military groups have
confirmed the beneficial effect caused by creatine supplementa-
tion on maximal muscle strength-endurance, anaerobic power
and speed endurance
44–47
using various exercise modes. These
studies could be used as a reference for the ‘athlete’in uniform
as maximal strength and power are increasingly being recog-
nised as potentially important components of military fitness.
48
However, optimising dosage selection is essential in order to
ensure the effectiveness of creatine loading. The amount, form
and frequency of creatine ingested should be examined as well
as the rate of creatine uptake (via biopsies or excretion in urine)
in order to determine the daily creatine gain. If these invasive
measurements are not feasible in military populations then a
simple monitoring of body weight increase (2–5%) within the
first 2–4 days of loading would be an adequate indication of effi-
cient creatine uptake in the muscle. This was mentioned as a
limitation in military studies,
38 40
where no significant differ-
ences existed in obstacle course performance following creatine
supplementation. Another possible explanation for the negative
results in that study
40
was probably the use of creatine supple-
ments in the form of sports bars which was not evaluated as
thoroughly in relation to creatine uptake in the muscle as other
forms such as creatine monohydrate.
1
The selection of the military sample group is another issue that
might influence the response to creatine supplementation. The
recruits in the study of Ensign et al,
38
were SOF units who
demonstrated smaller insignificant improvement in their perfor-
mances while, general military populations
40 43
showed signifi-
cant performance potentiation especially in strength abilities.
This may be explained by the elite group’s (Navy SEALs) intense
daily physical training giving elevated creatine levels in the
muscle which limits any further increase in intramuscular creatine
levels and consequently improvement in exercise performance,
which is supported by evidence from elite athletes from various
sports who follow intense training where creatine supplementa-
tion does not significantly improve exercise performance.
910
It is noteworthy that in aerobic sports, energy is predomin-
ately provided by aerobic degradation of carbohydrates (glycoly-
sis) and fat oxidation.
49
These procedures provide low and
constant energy supply but they do not relate to creatine metab-
olism. Alternatively, in power sports energy is predominately
provided by phosphates (CP, ATP) which are limited, but charac-
terised by high rates of energy supply.
50
On this occasion, main-
taining high phosphagen levels is heavily dependent on creatine
availability which rapidly replenishes CP and consequently
ensures the continuation of maximal-intensity exercise.
Additionally, during rest periods on an interval-type exercise,
creatine serves as an intramuscular high-energy phosphate
shuttle between the mitochondria (site of ATP production) and
myosin cross-bridge sites that initiate muscular contraction (site
of ATP utilisation).
51
In that sense, during the most intense and
short periods of exercise, the muscle will tax the creatine stores
most highly,
52
leading to a potentiating effect, following exogen-
ous creatine loading, mainly in short-duration sports involving
repeated and sudden bursts of movement (sprints, jumps).
Havenetidis K. J R Army Med Corps 2016;162:242–248. doi:10.1136/jramc-2014-000400 245
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This suggests that the selection of the exercise protocol for
evaluating creatine effects on military performance is highly
relevant. The obstacle course timings showed insignificant and/
or small improvements in the creatine group,
38 40
possibly
because it is dependent on energy sources from anaerobic and
aerobic pathways which are less creatine-dependent. Similarly,
the use of continuous, submaximal activity (5 km run and
10 km march) in the study of Bennet et al,
39
possibly excluded
the facilitation of exogenous creatine on energy supply during
initiation and/or rest periods due to the predominance of other
energy pathways. Marksmanship which was also used as a per-
formance measure in the study of Warber et al,
40
was not
affected by creatine supplementation, presumably due to the
technical rather than the metabolic demands that characterise
this military task. Hence, failure to relate the military occupa-
tional tasks as well as the appropriate fitness test used with the
energetics of creatine metabolism, may limit the validity of the
conclusions of these experiments.
38–43
Additionally, it is preferable not to use the ‘traditional’mili-
tary fitness tests (2 min push-ups, 1 min sit-ups, pull-ups, 2 min
curl-ups) since they are not representative indicators of perform-
ance of typical, loaded military tasks. Furthermore they impose
a systematic bias against larger participants.
53
A possibly success-
ful schema would be the use of militarily relevant tests consist-
ing of strength/sprint exercise type such as a timed 400 m run
with an 18 kg load, a timed simulated casualty rescue with the
fighting load, a repetitive lift and carry, single lift of a weighted
ammunition box, a carry task, a fire-manoeuvre sequence and a
trench dig.
54 55
These tests have been shown to be reliable,
54
and valid as they simulate common battlefield activities where
soldiers sprint to cover and move their body mass and transport
wounded soldiers, weapons and/or supplies requiring absolute
strength, speed and power.
There is a growing number of studies,
18 20 21 56 57
which
indicate positive effects of creatine supplementation on exercise
performance and on several aspects of the health and wellness
spectrum. This spectrum currently represents the new approach
to fitness in the military called ‘total force fitness’which seam-
lessly combines multiple components of fitness in the mind and
the body.
58
It seems that potentially, several fitness components
besides the physical (strength, muscle endurance, speed, power,
agility) can be facilitated by creatine supplementation. These
include nutritional, medical and psychological components.
One of the goals of nutritional fitness is to establish and meet
specific nutritional requirements, a procedure which varies
between individuals as in the case of vegetarians, who exclude
meat products and consequently creatine from the diet. Since
many military missions demand high speed and explosive
power, which rely on CP availability, creatine supplementation
will provide an alternative method to increase CP stores and
consequently maximise nutritional fitness without altering per-
sonal dietary habits. It has been reported that individuals with a
lower initial level of total muscle creatine content possess higher
potential to improve performance in response to creatine sup-
plementation.
1
Medical fitness refers to an injury-free, optimal
and healthy status where the warfighter is characterised by the
highest physiological and psychological readiness.
59
Studies
18 21
indicate that creatine supplementation can be an effective strat-
egy for maximising medical fitness by attenuating the loss in
muscle-mass-strength during immobilisation, acting as an effect-
ive antioxidant agent after more intense resistance training ses-
sions,
1
and improving the force-velocity relationship as well as
mean muscle fibre conduction velocity during voluntary and
electrically induced contractions.
20
These beneficial actions can
play a crucial role during short rehabilitation periods in ensuring
rapid deployment and/or during long-lasting treatment after
serious injuries (blast injuries, bone fractures) and in achieving a
full restoration of skeletal and neuromuscular function.
Psychological fitness is defined as the integration and optimisa-
tion of mental, emotional, and behavioural abilities and capaci-
ties in order to optimise performance and strengthen the
resilience of warfighters.
60
It seems that creatine supplementa-
tion can positively influence many aspects of psychological
fitness such as awareness, coping, decision making, resilience,
burn-out and engagement which are hindered by sleep depriv-
ation and impair the soldiers’capacity to successfully fulfil their
missions. Two studies
56 57
demonstrated that the creatine-
supplemented group presented a substantial resistance to cogni-
tive and psychomotor performance deterioration (choice reac-
tion time, balance, number of errors) as well as in mood swings
in individuals suffering from 24-h sleep deprivation. However,
there is still a need for targeted research with greater representa-
tion among military groups and the use of a plethora of military
occupational tasks in order to quantify any potential benefits of
creatine and minimise any clinical risks.
Health and ethical issues
Most anecdotal reports of side effects have described an
increased incidence of dehydration or muscle cramping or
gastrointestinal distress,
61 62
especially in athletes who exercise
in hot and humid environments. These potential side effects
were based on athletic media reports in the late 1990s, were
never supported by clinical evidence and the athletes did not
report a consistent pattern of ‘perceived’negative side effects as
a result of the creatine-supplementation protocol.
63
A recent
meta-analysis found no evidence to support the concept that
creatine supplementation either hinders the body’s ability to dis-
sipate heat or negatively affects the athlete’s body fluid
balance.
64
In fact, in most of the studies it was demonstrated
that creatine ingestion may actually have promoted hydration,
and reduce thermal stress during exercise in the heat.
11 63 65–68
Other studies have also demonstrated that creatine ingestion
has no negative effects on renal, hepatic, cardiac or muscle func-
tion.
69–72
Furthermore, the incidence of human adverse reac-
tions is limited and not necessarily linked to creatine itself, but
rather to violation of the creatine supplementation protocols for
potentially greater enhancement.
69
However, one of the greatest
concerns about creatine use is that few authors have examined
its long-term effects on users’health. Kim et al,
73
suggested that
exogenous creatine in quantities greater than 3–5 g/day is con-
sidered to apply a heavy load on kidney function and should
not be used by individuals with pre-existing renal disease or
those with a potential risk of renal dysfunction such as diabetes,
hypertension or reduced glomerular filtration rate. Considering
that in the loading phase a typical creatine regime includes 20–
25 g/day, this high quantity combined with a long supplementa-
tion period can potentially cause a cumulative detrimental effect
on users’renal health. Additionally, military groups such as SOF
units operating under hot and humid conditions for long
periods while carrying heavy loads
74
may magnify potential
adverse health effects of creatine which are considered negligible
in athletes who participate in controllable short-term exercise
trials.
The evidence supports the advice that creatine users should
not: become hypohydrated during exercise,
15 75
with reductions
in water intake less than 1.5–2 L/day, ingest creatine doses more
than 20–25 g/day and 5–7 g/day for the loading and mainten-
ance phase, respectively,
76
extend the supplementation period
246 Havenetidis K. J R Army Med Corps 2016;162:242–248. doi:10.1136/jramc-2014-000400
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longer than 7 days and 120 days for the loading and mainten-
ance phases, respectively,
77
and follow strenuous exercise proto-
cols under hot environmental conditions for extended time
periods, since no authors have examined the long-term effects
of creatine on thermoregulation.
64
Considering that the
mechanisms of creatine action are incompletely understood and
therefore, the long-term clinical safety cannot be guaranteed,
these guidelines may serve as a means of health prevention mea-
sures. Furthermore, annual training plans need to be designed
by military professionals which will embody scientific method-
ology by the use of periodisation models, acclimatisation techni-
ques and nutritional support in order to avoid health problems
in military servicemen caused by intense training and not by cre-
atine per se. There is also concern about the synergistic or
antagonistic role of creatine in relation to other supplements
such as caffeine,
78
vitamins,
79
as well as the potential risks that
might emerge from its frequent mixture with unknown sub-
stances.
80
These phenomena underscore the conduction of
recent surveys by the military management where the efficacy
and safety of various forms of creatine will be assessed based on
its interaction with other supplements/pharmaceuticals.
In relation to the ethical aspect of creatine supplementation
on military populations, it must be noted that currently it does
not appear on the International Olympic Committee’s list of
banned substances, while some ergogenic aids are banned by
sporting governing bodies due to their detrimental effects on
athletes’health, while others are deemed to confer what is seen
to be an unfair advantage. These considerations might raise the
ethical question as to whether the use of creatine should be
banned above specific concentration levels, based on its ergo-
genic effect akin to the former ban on caffeine which is a
normal dietary component. Such a prohibition would be diffi-
cult to enforce due to the difficulties in detecting creatine turn-
over because it is produced naturally by the body and is part of
any normal meat-containing diet; even with the use of repeated
muscle biopsies (which is not feasible in military populations)
this prohibition might end up punishing servicemen who are at
the top of the biological range in terms of muscle creatine
levels.
CONCLUSIONS
Although research on creatine involved early experimental con-
tributions on such diverse topics as high-energy compounds,
urinary constituents and diagnosis of myocardial infarctions,
this simple compound has not yet, after 150 years, yielded all its
secrets. Despite the relatively short time of investigation consid-
erable published research indicates that creatine ingestion is a
new ergogenic aid to enhance exercise performance. This
review has provided some insight into the use of creatine sup-
plements by military personnel, the effects on military exercise
performance, the methodology involved in the few experimental
studies performed and how this methodology affected the parti-
cipants’abilities under baseline/placebo and creatine conditions.
A series of military surveys have clearly shown that creatine has
rapidly become one of the most popular, legal and safe supple-
ments among military personnel, even though there is little
data, regarding its long-term effects.
The limited experimental research also suggests that short-
term creatine supplementation is not related to a significantly
enhanced physical performance in the military. It seems that
possible potentiating effects in the military may be masked if
specific guidelines are not followed in terms of creatine dosage,
military fitness testing and sample group selection. Under these
circumstances, the possibility that creatine supplementation may
enhance military exercise performance should be investigated
further, in order to allow data to be applicable and compatible
with the new holistic doctrine for military fitness.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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