Caffeine – does it really enhance performance?

For many athletes, caffeine is a “go to” before competition. It has long been regarded as an easy, convenient way to get a bit of a performance gain. Cyclists often indulge in a pre-race coffee; and many sports supplements now contain a small amount of caffeine to provide an extra bit of “kick”. But does it actually enhance performance to any significant degree; or are athletes just getting the benefits of the placebo effect?



Primarily, caffeine is a Central Nervous System (CNS) stimulant. The CNS consists of the brain and spinal cord; and is responsible for controlling most of the body’s functions. As a result, caffeine has been shown to increase heart rate and mental alertness, as well as increasing respiratory rate in some individuals. Stimulation of the CNS also has an effect on the way nerve fibres work on muscles.

In addition to being a CNS stimulant, there are a few other effects which caffeine has on the body; such as increasing endorphin secretions and utilisation of glycogen and fatty acids. These mechanisms, in addition to others, have been studied to determine if they have any affects on sports performance.


A lot of research into the performance benefits of caffeine has taken place over the years. Results from clinical trials are sometimes questioned, as much of the research does not involve “real world” scenarios. Data is often taken during simulated events; while actual in-competition data from elite athletes is not commonly found. In addition, the day to day variability of an athlete’s performance can make it difficult to show if the gains are a result of caffeine; or just minor, natural day to day changes in performance.


Having said that, much of the research tends to show that caffeine does actually provide performance gains for athletes. This absolutely brilliant summary from the International Society of Sports Nutrition, published in 2010, collates the results of a large number of high quality research papers. It summarises that:

The scientific literature associated with caffeine supplementation is extensive. It is evident that caffeine is indeed ergogenic to sport performance but is specific to condition of the athlete as well as intensity, duration, and mode of exercise. Therefore, after reviewing the available literature, the following conclusions can be drawn:

• Caffeine is more powerful when consumed in an anhydrous state (capsule/tablet, powder), as compared to coffee.

• The majority of research has utilized a protocol where caffeine is ingested 60 min prior to performance to ensure optimal absorption; however, it has also been shown that caffeine can enhance performance when consumed 15-30 min prior to exercise.

• Caffeine is effective for enhancing various types of performance when consumed in low-to-moderate doses (~3-6 mg/kg); moreover, there is no further benefit when consumed at higher dosages (≥ 9 mg/kg).

• During periods of sleep deprivation, caffeine can act to enhance alertness and vigilance, which has been shown to be an effective aid for special operations military personnel, as well as athletes during times of exhaustive exercise that requires sustained focus.

• Caffeine is an effective ergogenic aid for sustained maximal endurance activity, and has also been shown to be very effective for enhancing time trial performance.

• Recently, it has been demonstrated that caffeine can enhance, not inhibit, glycogen resynthesis during the recovery phase of exercise.

• Caffeine is beneficial for high-intensity exercise of prolonged duration (including team sports such as soccer, field hockey, rowing, etc.), but the enhancement in performance is specific to conditioned athletes.

• The literature is inconsistent when applied to strength and power activities or sports. It is not clear whether the discrepancies in results are due to differences in training protocols, training or fitness level of the subjects, etc. Nonetheless, more studies are needed to establish the effects of caffeine vis a vis strength-power sports.

• Research pertaining exclusively to women is limited; however, recent studies have shown a benefit for conditioned strength-power female athletes and a moderate increase in performance for recreationally active women.

• The scientific literature does not support caffeine-induced dieresis during exercise. In fact, several studies have failed to show any change in sweat rate, total water loss, or negative change in fluid balance that would adversely affect performance, even under conditions of heat stress.

To put it simply, YES! Many athletes will indeed find some performance benefits from caffeine!


Prior to 2004, caffeine was on WADA’s banned substance list in higher concentrations, only allowing up to 12 micrograms/ml in urine (which equates to roughly 8 cups of espresso) before athletes would be in any trouble. Since then, caffeine has not appeared on the banned list, so many athletes have been taking it for a bit of performance enhancement.

But earlier this year, WADA placed caffeine on the list of “monitored substances”, which means they are assessing if athletes are using it with the intent of enhancing performance. If they find that caffeine does in fact provide significant benefits in performance, it may just find its way back onto the banned substance list for 2018.


Many athletes try to get as much out of their body as possible in order to maximise their performance. Using different training techniques, trialling different types of recovery, refining their diet……all fair enough. But some go to the point of researching and using different substances to see what performance gains can be attained.


As an athlete, is it worth taking something you don’t need, potentially risking your health, in order to be just that little bit better? And is it okay to enhance your performance, by taking a substance which is known to give you a bit of a boost, just because that substance isn’t found on the banned list?


The results of a large number of research studies show there are performance gains to be found from caffeine for many athletes. Gains in performance may be seen from ingesting around 3-6mg of caffeine for every kilogram of body weight…..and with WADA currently reviewing the use of caffeine in sport, its pretty clear that performance gains are there. But considering the review currently taking place by WADA, things may change. Very soon, it may not be the best idea to indulge in that pre-event espresso……

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