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Editor Note: Caffeine ingestion is only suggested for post-pubescent athletes. Despite the common use of caffeine, high doses may cause cardiac stress. If unsure about dosing and usage, consult your physician.

Inflammation is a common topic of conversation at Swimming Science. For a background on this topic, consider reading:

As always, more research results in more questions, not answers. This is especially the case when the study is performed on running or another sport and extrapolations are made. Tauler (2013) in the journal Med Sci Sports Exercise analyzed the effects of caffeine on the inflammatory response induced by a 15-km run. Once again, this study looked at running, which does not transfer to swimming, but extreme endurance exercise does not receive much attention, requiring some extrapolation. However, running does likely cause a lot more inflammation than swimming secondary to gravity and the repeated ground reaction forces. 

In this study, 36 recreationally trained athletes performed a double-blinded study of caffeine or placebo trial. Before the trial, the subjects gave blood, performed anthropometrical measurements, then consumed a standardized breakfast (a specific breakfast comprising a sandwich (60 g bread, 25 g turkey or ham, 25 g cheese and 20 g lettuce), 50 ml of decaffeinated coffee, 200 ml of semi-skimmed milk and water ad libitum.). One hour before competition, athletes took 6 mg/g of caffeine in a yellow apple juice drink or simply the apple juice drink. The exercise was a 15-Km run where heart rate was taken continuously and blood samples were taken after the race. The participants had no differences in habitual caffeine intake. 

The athletes lost approximately 2 kg weight during the race. The caffeine group had significantly increased plasma adrenaline, plasma glucose, IL-6, IL-10, MDA (oxidative stress marker), LOOH (oxidative stress marker for ferric-xylenol), leukocyte number, neutrophil number, and plasma lactate compared to the control group. However, no significant differences were observed between plasma free fatty acids levels, vitamin C, A, or E, concentrations, lymphocyte count. 

This demonstrated numerous differences in the caffeine supplementation group compared to the control. Specifically, the increase in IL-6 and IL-10 indicates an increase response to inflammation, potentially due to an increase in adrenaline and lactate levels. Moreover, the oxidative stress during exercise likely increased. In short, caffeine supplementation increases interleukin-6 and -10 responses during aerobic exercise. Future studies should consider improved performance as a cause for the noted changes in blood markers.

Once again, more questions exist. One specifically, is the timing of caffeine consumption. Tauler (2013) provided the athletes caffeine one hour prior to the trial, but another study looked compared cycling performance (of a sprint cycling effort) after caffeine gum consumption 120-minutes, 60-minutes, and 5-minutes precycling (Ryan 2013). 

“The subjects were instructed to chew the gum for 5 minutes and then expectorate the gum. In 3 of the 4 visits, at 1 of the time points mentioned previously, 300 mg of CAF was administered. During the fourth visit, placebo gum was administered at all 3 time points (Ryan 2013).”


Blood sampling was taken periodically during the experimental trials.




Gum administration 1 - 2 hours before cycling did not enhance performance, whereas consumption 5 minutes prior to exercise improved results.



Acute administration of caffeine gum appears the most beneficial for performance. Moreover, elevating plasma caffeine levels appears necessary for cycling time trial enhancement. 

If administering caffeine as an ergogenic aid, gum appears indicated in acute situations. It also suggests exercise enhancement occurs during the rise of caffeine in plasma. Therefore, less time lapse should occur between pill or liquid caffeine consumption and performance (approximately 30 - 45 minutes). Endurance exercise trials should compare different times of caffeine consumption on performance.



  1. Tauler P, Martínez S, Moreno C, Monjo M, Martínez P, Aguiló A. Effects of Caffeine on the Inflammatory Response Induced by a 15-km Run Competition. Med Sci Sports Exerc. 2013 Jan 4. [Epub ahead of print] 
  2. Ryan EJ, Kim CH, Fickes EJ, Williamson M, Muller MD, Barkley JE, Gunstad J, Glickman EL.Caffeine gum and cycling performance: a timing study.

    J Strength Cond Res. 2013 Jan;27(1):259-64. doi: 10.1519/JSC.0b013e3182541d03.


By Dr. G. John Mullen received his Doctorate in Physical Therapy from the University of Southern California and a Bachelor of Science of Health from Purdue University. He is the founder of the Center of Optimal Restoration, head strength coach at Santa Clara Swim Club, creator of the Swimmer's Shoulder System, and chief editor of the Swimming Science Research Review.

Dr. John Mullen, DPT, CSCS world-renowned physical therapist and strength coach.
  1. April 3, 2013

    Would like to see a constant reminder as to the appropriateness of caffeine supplementation as it refers to athlete age and in general the usage of this for all athletes when swimsci posts about caffeine as it relates to swimming competition..

    As a Head Coach for a club where 80 percent of my club is under the age of 14, caffeine is not the answer for success in a race. Uninformed parents make ill-advised choices at meets, like cans of redbull or 5 hour energy before races.

    I would expect that the majority of your readers are responsible people, The random swim parent (or heaven for bid coach) coming across this article in a google search shows that caffeine works, but it does not say for whom it is appropriate for.

    “with great knowledge comes great responsibility”

  2. April 3, 2013

    Thank you coach Erik, short disclaimer posted.

  3. April 4, 2013

    Much appreciated, keep up the good work swimsci!

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