Caffeine is one of the most widely used supplements in the world, especially among tactical groups. It is a central nervous system (CNS) and metabolic stimulant used to reduce feelings of fatigue and to restore mental acuity. Many studies have demonstrated the exercise performance–enhancing effects of caffeine. The traditional hypothesis is that caffeine increases the levels of fight-or-flight chemical messengers, including epinephrine and norepinephrine, which promote fat utilization and result in the sparing of intramuscular glycogen. Furthermore, there are strong data to support the use of caffeine for enhancing mood, vigilance and focus, energy, and marksmanship all important components of tactical performance. The benefits of caffeine have been repeatedly shown, especially in military personnel. The Committee on Military Nutrition Research and the Food and Nutrition Board have accepted that 150mg of caffeine will increase endurance and physical performance among military personnel. Additionally, a dose of 200 mg has been shown to improve focus and vigilance during a shooting task, despite 72 hours of continuous sleep deprivation. Also, successive caffeine intake (four 200 mg doses over 24 hours) in the late evening and early morning aided in maintaining cognitive function over a three-day period with minimal sleep. In addition, caffeine may help tactical athletes by positively influencing their psychological state and altering their pain perception. Research has shown caffeine supplementation to result in reduced rating of perceived exertion during constant load exercise, which may translate to improved training volume and thresholds during military tasks. The risk of caffeine at appropriate doses is low, while the benefits are high. However, it is suggested that athletes take an initial dose of 3 mg/kg body weight to test for caffeine sensitivity. The overconsumption of caffeine from a variety of sources, such as chewing gum with coffee, soda, and blended supplements, causes adverse effects in tactical personnel, so care should be taken to assess all caffeine sources. Of interest to tactical personnel, cycling from high to low (or no) caffeine intake may increase physiological sensitivity.

Key Points About Caffeine

• Doses of 200 mg consumed 30 to 60 minutes before exercise appear to be most effective for physical and e performance.

• Caffeine may enhance fat oxidation and spare carbohydrate, which may improve performance.

• Evidence suggests that a beneficial effect from caffeine can be achieved with a dose of 1.4 to 4.0 mg/lb (mg/0.5 kg) body weight. This would equate to 266 to 760 mg for a 190-pound (86 kg) person.

• Overconsumption of caffeine can result in negative side effects.

• To date, the largest amount of caffeine ingested by tactical personnel in controlled studies was 800 mg (consumed in four divided doses of 200 mg) over a 24-hour period, with no adverse effects in caffeine-naive and caffeine-habituated Special Forces personnel.