Does Caffeine Improve Athletic Performance?

Caffeine has been used and enjoyed for making people more alert and fighting mental fatigue for centuries, and there is ample research on the effects of caffeine on athletic performance. The evidence suggests that caffeine enhances endurance performance, muscular strength, and exercise capacity in general and that it does so at modest doses.

There are some caveats in the literature: Coffee is not always an effective delivery for caffeine because caffeine per serving varies. Individual variability means that some people experience physical benefits from caffeine while others (nonresponders) do not. And the dose-response of caffeine plateaus at low intake levels. (Burke 2008.) Despite these caveats, there are both anecdotal and researched-based reasons that many of us rely on caffeine for a daily boost, whether waking up, increased productivity, or a new PR. (Id., “Caffeine is a drug that enjoys social acceptance and wide-spread use around the world, with about 90% of adults consuming  it  in  their  everyday  eating  patterns.”)

How caffeine boosts athletic performance is an ongoing investigation: does it increase muscular power? Or are its benefits purely mental, waking you up and building confidence for that next big lift? Because caffeine as a performance enhancer has been seen in multiple settings—strength, endurance, cognitive performance—finding the intersection between these tasks may help understand caffeine’s effects better. For example, it had been thought that caffeine enhanced fat oxidation while sparing limited and critical muscle glycogen stores. (Warren et al. 2009.) While this would help explain improvements in endurance performance, it does not explain performance-improving effects for strength and power production where high-intensity and short-duration efforts dominate. One should note, however, that while some studies report a “significant overall beneficial effect of caffeine on [maximal voluntary contraction] strength,” others have said just the opposite. (See, e.g., Polito et al. (2016); but see, Grgic & Mikulic (2017).) Different studies attribute their different results to the way types of force production measured and selection criteria for their meta-analyses, suggesting an inherent complexity to this issue.

The answer to caffeine’s mechanism for strength benefits may lie in what we are learning about fatigue and force production. When you produce force against an object, there is a long chain of events that begins in the CNS and ends with muscle contraction, a motor pathway. Fatigue—the measurable loss of the ability to produce force—may occur at any or multiple links in the chain, generally separating into two categories: peripheral fatigue and central fatigue. Peripheral fatigue describes problems in the motor pathway originating at the junction between a motor neuron and a muscle fiber or farther down the chain that produces a voluntary muscular contraction, including depleted energy stores, muscle impairment due to damage to the fibers, or an impaired muscular response due to accumulated byproducts or exercise-induced muscle damage. Central fatigue describes motor impairment that originates in the CNS, likely as a protective mechanism. Your CNS integrates input from various sources of the body, limiting muscle contraction and force production when that input suggests that doing so would be beneficial to your continued survival. CNS down-regulation of force production comes from many possible sources, including everything from mental fatigue to self-belief and superstition. (Noakes 2012.)

The investigation into caffeine must ask a similar question: does caffeine affects muscles and their periphery, the CNS, or both. (See Warren 2009.) Though research does not connect the wakefulness effects of caffeine to its performance-enhancing attributes, this breakdown of peripheral vs. central effects is helpful to understanding where along the motor pathway it might be assisting your ability to produce force and lockout that new PR.

To the extent that caffeine boosts your strength workout, it likely works centrally, affecting your CNS and the regulation of force production. One analysis comes to this conclusion, in part, by contrasting improved force production during voluntary muscular contractions and no observed improvement of “electrically stimulated strength.” (Warren) Other theories relate these improvements to pain perceptions, suggesting that caffeine can act on the nervous system and affect pain and perceived exertion thresholds. Ultimately, any athletic benefits probably depend on the type of exertion, the mechanism, and individual variability. So, while coffee won’t give you actual superpowers, if you love it, drink up. And maybe take your travel mug the next time you train; it may just give you that extra oomph!

Press Pot Coffee

To help, here is a recipe for perfect press pot coffee every time:

What you need:

• Water temperature: 204°F
• Coffee: Course ground
• A food scale for precise measuring
• Ratio: Coffee to water; 1:16 (grams to grams). If you have 25 grams of coffee, you are going to use 400 grams of water, which will yield approximately 12 fl. Oz of coffee when brewed.

Grind your coffee with a coarse grind—more coarsely than you would for a drip coffee machine.  Place your press pot on your food scale, and add your coffee. Using the ratio above to figure out how much hot water you are going to add.

1. Start a timer and add ½ of your water
2. let the coffee “bloom” for 30 seconds.
3. At 0:30, finish adding the rest of your water to the pot. Stir gently, cover, and let the grounds settle.
4. Stir again gently at 3:45.
5. The brew is finished at 4:30. Add your filter, compress, pour, and enjoy!

References

Grgic & Mikulic, “Caffeine ingestion acutely enhances muscular strength and power but not muscular endurance in resistance-trained men,” European Journal of Sport Science, Vol. 17, No. 8, 1029–1036 (2017)

Louise M. Burke, “Caffeine and Sports Performance,” Appl. Physiol. Nutr. Metab. 33 (2008)

Noakes “Fatigue is a brain-derived emotion that regulates the exercise behavior to ensure the protection of whole-body homeostasis” Front. Physiol. 11, (April 2012)

Polito, Souza, Casonatto, Farinatti, “Acute effect of caffeine consumption on isotonic muscular strength and endurance: A systematic review and meta-analysis,” Science & Sports 31, 119-128 (2016)

Warren, Park, Maresca, Mckibans, Millard-Stafford, “Effect of Caffeine Ingestion on Muscular Strength and Endurance: A Meta-Analysis,” Medicine and Science in Sports and Exercise (2009)