Caffeine physical performance

Falk, B., Burstein, R., Ashkenazi, I., Spillberg, O., Alter, J., Zylber-Katz, E., Rubinstein, A., Bashan, N., and Shapiro, Y., The effect of caffeine on physical performance after prolonged exercise, European Journal of Applied Physiology, 59, 168, 1989. 

McLellan, T. M., Bell, D. G., Kamimori, G. H. (2004). Caffeine improves physical performance during 24 h of active wakefulness. Aviat. Space Environ. Med. 75 (8), 666-72. 

The dividing line between what is and what is not acceptable practice is hard to draw. Caffeine can improve physical performance and illustrates the difficulty of deciding what is permissible or impermissible. A cup of coffee is part of a normal diet, but some consider taking the same amount of caffeine in a tablet, injection or suppository to be doping. ... 

Caffeine (from guarana, tea, chocolate, coffee, or as a pure form) and increased attention/alertness, reduction in the perceived effort, and increase in endurance capacity and physical performance during short-term high-intensity exercise. 

Williams, J. FT, Caffeine, neuromuscular function and high-intensity exercise performance, Journal of Sports Medicine and Physical Fitness, 31, 481, 1991. 

Within minutes of consumption, a caffeinated beverage will cause the drinker to feel more alert. Simple intellectual tasks are performed more readily, as are physical jobs that require endurance. However, while reaction time is shortened by caffeine, fine motor control suffers, perhaps due to the slight tremor that becomes more pronounced with higher doses of caffeine. The larger doses of caffeine, especially for people who do not use it regularly, cause headache and nervousness. 

A recent report by the Committee on Military Nutrition Research (81) recommended using caffeine doses of 100-600 mg to sustain the cognitive performance and physical endurance of military personnel, especially during periods of sleep deprivation. The Committee noted the fact that caffeine s effects appear particularly consistent in fatigued individuals. 

In summary, caffeine is a known psychostimulant that exerts positive effects on physical endurance, alertness, and vigilance. The effects on reaction time and EEG activity are debatable. Caffeine may cause small, but inconsequential, increases in blood pressure, particularly in people who do not habitually use this compound. Although the effects on mood are generally positive, increased anxiety may result from doses of 300 mg or more. Caffeine s most reliable effects appear to occur in sleep-deprived personnel in whom doses ranging from 250 to 600 mg (including sustained-release caffeine doses of 300-600 mg) have been shown to improve wakefulness, mood, and various aspects of performance. 

Lieberman HR. Caffeine. In Jones D, Smith A, eds. Factors Affecting Human Performance. Vol II. The Physical Environment. London Academic Press, 1992. 

In addition to common organic solvents, supercritical fluids (scf s) can be used for a great variety of extraction processes [158 165], Supercritical fluid extraction (SFE), mostly carried out with SC-CO2 as eluant, has many advantages compared to extractions with conventional solvents. The solvent strength of a supercritical fluid can easily be controlled by the pressure and temperature used for the extraction at a constant temperature, extraction at lower pressures will favour less polar analytes, while extraction at higher pressures will favour more polar and higher molar mass analytes. As supercritical fluids such as CO2 and N2O have low critical temperatures (tc = 31 °C and 36 °C, respectively), SFE can be performed at moderate temperatures to extract thermolabile compounds. Typical industrial applications using SC-CO2 include caffeine extraction from coffee beans [158] as well as fat and oil extraction from plant and animal tissues [165]. For some physical properties of supercritical solvents, see Section 3.2. 

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