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Caffeine (chemically a methylxanthine) is one of the best (if not THE best) researched ergogenic aids available today. Caffeine has been shown in several studies to promote fat oxidation and both weight and fat loss in exercising individuals.  Many studies repeatedly show that caffeine enhances both short term and long term endurance performance. Caffeine seems to delay fatigue (prolongs time to exhaustion) so aerobic workouts can go on longer and stronger. It has been shown to be effective in increasing speed in simulated race conditions and in a regular laboratory setting. One study published in the International Journal of Sports Medicine in 1998 states “caffeine ingestion can be an effective ergogenic aid for short term, supramaximal running performance.” Even though there are far less studies with caffeine and resistance training (weight lifting), some evidence does suggest that caffeine can increase power generated in repeated muscle contractions and enhance endurance at submaximal tension. More power = more reps hence better muscle gains, capish!  Caffeine works through several mechanisms of action including promoting the release of stored fat to be used as energy, more release of calcium from the sarcoplasmic reticulum (thereby leading to greater muscle contraction including greater force production by each motor unit), antagonism of the adenosine receptors mainly in the central nervous system, inhibition of phosphodiesterases leading to an increase level of cyclic AMP in muscle tissue (creating a more favorable intracellular environment in active muscle), and sparing glycogen (carbohydrate stores in muscle cells and the liver) because of an increased rate of fat oxidation (which could explain why caffeine delays time to exhaustion during aerobic exercise).  Caffeine has some diuretic properties that can aid in decreasing water retention in the body although it does not seem to act as a diuretic during exercise.  Anyway, it is important to consume plenty of water when taking in caffeine.  Another thing to look out for is caffeine’s effects on blood sugar.  Although not clear from the research, it may decrease insulin sensitivity so diabetics need to be careful.  Regularly consuming high doses may also adversely affect blood pressure.  Moderation is the key.  A regular cup of coffee has about 100 mg of caffeine per serving but some research shows that coffee is not as effective in maximizing the benefits of caffeine as is pure caffeine. Some people using higher doses of caffeine for ergogenic benefit sometimes report nervousness, jitteriness, and stomach discomfort.


A good dose is 200-600 mg of pure caffeine about 45 minutes to one hour before exercise or a big race (levels of caffeine peak about an hour after ingestion). Taking it on an empty stomach can further potentiate its effects. It’s interesting to note that some research indicates that pure caffeine is better than coffee. The stimulation effect of caffeine usually lasts about 2-4 hours after ingestion as caffeine has a short half life in the body. 


Don’t take within 4 hours of bed time as it may interfere with sleep.  Athletes who use caffeine sparingly and only when they really need it seem to have a better performance benefit due to reduced tolerance versus someone who uses caffeine all the time. It may be a good idea to cycle caffeine use and take days off from it here and there.  


Keep in mind that the upper limit of caffeine allowed by the International Olympic Committee (IOC) and the NCAA is 12mcg/ml in the urine which would equate to taking about 1000-1200mg of caffeine within about 4 hours of the drug test. This is a huge dose but remember, individuals vary so it is possible that some people can test positive for caffeine with even lesser amounts. 


There seems to be an upper dosage threshold in terms of using caffeine as an ergogenic aid—more does not seem to be better in this case. In fact, some research indicates that taking a low to moderate amount of caffeine is equally if not more effective than taking a much higher dose of caffeine. Green tea is a great alternative to regular coffee as it has polyphenols and a special compound called EGCG (epigallocatechin gallate) which can not only boost immune function but also enhance metabolic rate directly. 


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