Page 83 - Journal of Special Operations Medicine - Winter 2016

alertness. Interestingly, despite no direct effects on cog- in an anhydrous state (i.e., not in coffee or other bev-
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nitive performance, individuals do report enhanced, sub- erage) may have greater ergogenic properties. Coffee,
28
jective feelings about their performance when under the tea, and energy drinks contain other substances other
influence of caffeine, like increased vigor, elation, or pleas- than caffeine and many caffeinated drinks also have
antness. Likewise, caffeine appears to maintain cognitive high calorie content (e.g., energy drinks and blended
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capabilities during situations that impair vigilance (e.g., coffees). Most research studies have used caffeine in the
sleep deprivation, wearing chemical protective mask). 10 anhydrous state to control for the amount provided, and
while several have looked at coffee and energy drinks,
Restricted Sleep the results are mixed. 28,52 There is no doubt that caffeine
The use of stimulants like caffeine, modafinil, and am- alone has a bitter taste, so the use of caffeine gum may
phetamines haa been studied as “pharmacological coun- be a preferred option. Additionally, consuming caffeine
termeasures” to maintain performance during periods gum results in a faster rate of absorption (likely through
of limited sleep, and each drug has its own set of advan- the tissues lining the mouth) than the pill form, with
tages and disadvantages. For a review of this literature, comparable levels of caffeine in the systemic circulation,
see the assessment by Bonnet et al., which reports that at dose of 100mg (one piece) and 200mg (two pieces),
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caffeine was established as a safe and effective counter- suggesting an earlier onset of drug effects from the caf-
measure to combat fatigue and maintain cognitive per- feine gum. The caffeine gum “Military Energy” has
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formance across periods of sustained wakefulness. a national stock number and is available for purchase
through Department of Defense supply chain.
Caffeine has successfully been used to offset cognitive im-
pairments, 30,41-46 maintain vigilance and reaction time, 30,47 Regulations and Restrictions
and improve physical performance and marksman-
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ship. 47,49,50 Specifically, a regimen of repeated dosing of According to the US Food and Drug Administration,
caffeine at 200mg per dose, given at 2- to 3-hourly in- 400mg/day, or about four or five cups of coffee, is the
tervals, effectively sustains elevated caffeine levels (mea- amount of caffeine “not generally associated with dan-
sured in plasma) throughout a night of sleep loss. 43,51 gerous, negative effects” for healthy adults. Currently,
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Special Forces personnel, who consumed caffeine gum (in if caffeine is added to a food, beverage, or dietary sup-
three doses of 200mg each every 2–4 hours) during an plement, it must be included in the listing of ingredients
overnight field operation maintained vigilance (observa- on nutrition or supplement facts labels, but the actual
tion and reconnaissance vigilance task [ORVT]) and im- amount does not have to be listed if it is part of a “pro-
proved running performance (6.3km distance) over the prietary blend.” Importantly, the only time the FDA
period of sustained wakefulness. Additionally, a total explicitly approved adding caffeine was in the 1950s
29
daily dose of 800mg (200mg every 3.25–3.5 hours) of where it was ruled that caffeine is “generally recognized
caffeine was consumed during successive overnight pe- as safe” (GRAS) when used in cola-type beverages up
riods of sustained wakefulness as a strategy to maintain to a level of 0.02% or 200 parts per million (≤20mg of
cognitive function when sleep periods are not optimal caffeine per 100mL or 47.5mg/8oz serving). The rapid
55
or available. However, it is important to point out that increase in the number of caffeinated products on the
26
caffeine can interfere with the amount of sleep obtained market was never anticipated and regulations have not
when opportunities to sleep are provided (e.g., Kamimori kept up with manufacturers.
et al. ), so planning naps and caffeine use are important.
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This limited oversight is particularly true for energy
drinks in the United States. Although many were initially
Safe Use and Form of Caffeine
marketed as dietary supplements, most now have Nutri-
So what is a safe amount of caffeine to be consumed tion Facts labels and are considered foods. Regardless
under regular (non–sleep-deprived or performance) con- of the label, manufacturers are not required to disclose
ditions? As noted, more is not better and recommended the amount of caffeine, and this is a concern because
amounts to enhance performance and minimize risk it is usually added as a synthetic alkaloid rather than
range from 2 to 6mg/kg, but that means a 100kg per- a naturally occurring constituent of the beverage (as in
son would consume 600mg, which could be too much. tea or coffee). Levels of caffeine in energy drinks vary
Thus, the general rule has been 100mg up to 300mg. 43,51 widely, but may be between 20 and 316mg of caffeine
More studies are needed to evaluate whether 6mg/kg is per 8oz serving, with some well above the GRAS level.
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reasonable in the absence of data regarding the sensitiv- However, the caffeine content of coffee can also vary
ity and metabolic activity of an individual. widely (48–317mg per serving), depending on the roast-
ing temperature, extraction process and brewing tech-
With regard to form, much remains to be learned, but nique. Finally, large doses of caffeine are also found
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the current literature indicates that caffeine consumed in many workout supplements, and as one of the main

Caffeine and Performance 67