Intro: For years athletes have been using caffeine in various doses to improve their performance. Everyone knows that a strong cup of Java gives you that alertness and sense of extra energy. Drink three cups of leaded Starbucks coffee and you'll feel like you want to run a marathon! So... does the caffeine just make you want to run that marathon or do you actually run it and run it faster? Though many professional endurance athletes use caffeine to enhance their performance, the US Olympic Committee, World Anti-Doping Association (WADA) and US Anti-doping association ban certain substances, including caffeine, for safety reasons as well as any unfair advantages those substances may offer. Caffeine is banned at a level of 12mcg/ml in urine, which requires about 1,200 mg of pure caffeine or 8 cups of strong coffee. WADA has lifted this ban starting in January of 2004, although it comes with some controversy since caffeine does have some ergogenic properties and can be dangerous if abused. Back to that marathon: you can run it faster, but only if done correctly, so let's talk about who can benefit from caffeine and how it can be properly used.

Caffeine stimulates the central nervous system (CNS), increases the release of adrenaline, increases the use of body fat as fuel and spares glycogen. Adrenaline release is accomplished through caffeine's effect on epinephrine and nor-epinephrine. This CNS excitatory response is used by many athletes to give them that alertness and sense of extra 'energy' needed for their workouts. More importantly, caffeine mobilizes free fatty acids (FFA) in the blood. Increased FFA in the blood allows the body to use fat as a fuel source. The use of fat as fuel allows the body to spare glycogen (carbohydrates) for later use in exercise.

Notes to consider:
· Caffeine is classified as a diuretic. This can complicate an athlete's water balance, which determines how efficient he/she will perform. Diuretics not only dehydrate the body, they can cause bowel movements and gastric distress which would obviously be detrimental to your exercise bout.
· Habitual caffeine users will not see any ergogenic effects from caffeine prior to a race. Your body has an intricate natural defense mechanism (builds a tolerance) which over time compensates for high doses of most nutrients and chemicals you put in your body. In other words, if you habitually use caffeine you can expect your body to reduce all the beneficial endurance and performance effects.
· Caffeine is also a thermogenic. This means it will raise your heartbeat and core body temperature. As you can guess, this may not be wise when exercising in heat.
· Caffeine has not shown any benefit on power and strength.

The previous four points may lead you to believe that caffeine should not be used by anyone as an ergogenic aid. In fact, the majority of the research on sedentary individuals does not support the use of caffeine as an ergogenic aid. However, the research done on trained athletes showed no detrimental diuretic effect and no increased body temperature. Trained athletes who are also habitual caffeine users can get benefit from caffeine if they abstain at least three days prior to the event. Even though caffeine does not increase power, it has been shown to reduce the perceived effort at a given workload, e.g., cycling at 24mph may seem easier when loading with caffeine.

Recommendations:
Do not use any caffeine for three days (or more) prior to an event. Start 3 to 4 hours prior to your event and consume 3mg - 6mg of caffeine per kg body weight (that's 210mg to 420mg for a 150lb athlete).* This is a large amount of caffeine, so be sure to experiment before you do this with incremental levels of caffeine.* If you are not trained, then you are better off not using caffeine at all.

If you choose to load with caffeine prior to training or an event, make sure to use products which clearly list total caffeine content. Many energy drinks list caffeine, green tea or guarana on the label but do not list total caffeine content. Most of these drinks offer minimal levels of caffeine (5mg-40mg).

WADA's removal of caffeine from its banned substance list does raise some serious concerns. If abused caffeine can be detrimental and dangerous. Caffeine's actions on the CNS, excitory response and potential as a diuretic can all cause serious damage if abused. We strongly urge all athletes wanting to use caffeine to do so under extreme caution.

*Excess caffeine can cause anxiety, irritability, delirium and hallucinations. Caffeine increases core body temperature and heart rate. Consult a physician before using caffeine prior to exercise.

Typical Caffeine amounts:
Soda: 50mg caffeine
Cup of Coffee: 50 - 150mg caffeine
Cup of tea: 10 - 50mg caffeine
Guarana: active ingredient is caffeine (8% to 15%)
Green tea herb: active ingredient is caffeine (0% to 15%) I.E. 100mg of Green Tea extract provides between 0mg and 15mg total caffeine content.

References:
1: J Appl Physiol 2000 Nov;89(5):1837-44 Comparison of caffeine and theophylline ingestion: exercise metabolism and endurance. Greer F, Friars D, Graham TE Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada N1G 2W1.

2: Costill DL, Dalsky GP, Fink WJ. Effects of caffeine ingestion on metabolism and exercise performance. Med Sci Sports Exercise. 1978; 10: 155-158

3: Ivy JL, Costill DL, Fink WJ, et al. Influence of caffeine and carbohydrate feedings on endurance performance Med Science Sports and Exercise. 1979; 11;6-1

4: Essig D, Costill DL, Van Handel RJ. Efects of caffeine ingestion on utilization of muscle glygogen and lipid during leg ergometer cycling. International Journal of Sports Med. 1980; 1:86-90

5: Fisher SM, McMurray RG, Berry M, et al. Influence of caffeine on exercise performance in habitual caffeine users. International Journal of Sports Med 1986;7:276-280

6. World Anti-Doping Association http://www.wada-ama.org