Java Jolt - Caffeine and Endurance Performance

Researchers have laboriously studied the effects of caffeine on sports performance with very optimistic results.  Caffeine has been known to increase wakefulness, reduce fatigue, and increase alertness.  This knowledge has been known for centuries and has been put into practice by around 90% of the adult population.  I myself require a coffee every morning to start my day off.  In addition to that, caffeine addiction is prevalent and symptoms of withdrawl can be observed for people who attempt to ‘quit’ drinking the miracle brew.  Again, I can attest to the withdrawl symptoms, and if I haven’t had my morning brew – get outta my way!

Back to the research surrounding caffeine ingestion and performance, which has had mixed results.  Caffeine can be found in coffee, sports drinks, energy drinks, capsules, and specific supplements.   Much research has been conducted and one main finding which seems to be accepted throughout is that the most effective form of caffeine is from capsules.  Some research assumes that another component of the drinks (coffee and energy drinks) works to antagonize the actual affects of coffee.

Caffeine has proven to improve endurance performance ranging from activities 30 to 120 minutes in duration.  So what makes caffeine such a potent ergogenic aid?  Research has shown (to different extents) that caffeine blocks adenosine receptors, increases lypolysis, increases catecholamine release, increases cortisol release, increases potassium release, increases levels of intracellular calcium, inhibits cAMP phosphodiesterase activity,  produces central nervous system activation and increased respiratory ventilation, PLUS functions as an antioxidant (Sinclair & Geiger, 2000).  I will explain a few of the most important affects of caffeine, but for a full review, please refer to the journal by Sinclair & Geiger titled Caffeine use in sports.

Increased lypolysis is crucial for endurance performance because energy is produced from the breakdown of fats (event called lypolysis).  Increased catecholamine release, epinephrine to be exact, causes increased circulation of free fatty acids and vasodilation of blood vessels to increase blood flow to exercising tissue.  Cortisol levels increase during exercise and improves athletic efficiency.  Increased intracellular concentration of calcium is facilitates the excitation-contraction coupling mechanism for skeletal muscle.

Now that I have stated all the positives regarding caffeine, I must inform you of the consequences.  One is that caffeine can be addicting and individuals become habituated to the effects of caffeine.  This ultimately results in increased consumption of the substance so that its effects can be felt.  In addition, as mentioned earlier, withdrawl symptoms can be observed when an individual stops ingesting caffeine.  Caffeine is also I diuretic which may cause athletes to urinate excessively, but the diuretic properties of caffeine do not occur during exercise.  Caffeine can cause sleeping problems and can inhibit the function of adenosine induced erythropoietin (hormone which stimulates red blood cell formation). 

So what does research suggest? Through much of the scientific literature, it seems evident that the adequate amount of caffeine to ingest is 2-3 mg/kg of body weight before and (or) during exercise.  Ingesting more caffeine than this amount does not increase performance, it may actually have adverse effects.  As an aside, in 2003, the Olympic Movement Anti-Doping Code included caffeine as a banned stimulant.  If an athlete’s urine caffeine concentration was greater than 12ug/mL, they were disqualified.

I am not saying that the missing link in your training is caffeine supplementation.  You must do your research before attempting to change your diet, especially with supplements.  Caffeine has positive and negative effects; therefore it is up to you to decide if you wish to pursue ingestion.  I have provided the list of journals and studies I read to write this article so please feel free to draw your own conclusions from them as well.  Click here to gather a list of articles using the popular Google Scholar which searches through peer reviewed journals. 

References

Bell, D.G. & McLellan, T.M. (2003).  Effect of repeated caffeine ingestion on repeated exhaustive exercise endurance.  Official Journal of the American College of Sports Medicine, 35(8), 1348-1354.

Burke, L.M. (2008).  Caffeine and sports performance.  Applied Physiology, Nutrition, and Metabolism 33, 1319-1334.

Conger, S.A, Warren, G.L., Hardy, M.A., & Millard-Stafford, M.L. (2011).  Does caffeine added to carbohydrate provide additional ergogenic benefit of endurance?  International Journal of Sport Nutrition and Exercise Metabolism 21, 71-84.

Graham, T.E., Hibbert, E., & Sathasivam, P. (1998).  Metabolic and exercise endurance effects of coffee and caffeine ingestion. Journal of Applied Physiology 85, 883-889.

Sinclair, C.J.D. & Geiger, J.D. (2000).  Caffeine use in sports: A pharmacological review.  Journal of Sports Medicine and Physical Fitness, 40, 71-79.