We previously discussed the background of caffeine and highlighted its use as an ergogenic aid. In this deep dive, we will cover the performance benefits of caffeine and how to integrate caffeine into training and competition to improve your performance.
Using caffeine for performance
Caffeine has been consistently shown to improve endurance exercise performance when taken in amounts of 3-6 mg/kg of body weight. No significant benefit is seen in dosage above 6 mg/kg body weight. Caffeine improves endurance performance primarily through its effects on the central nervous system. This results in the following:
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Improves cognitive acuity (focus) and blunts pain response/reduces perceived exertion levels through stimulation of the sympathetic nervous system (i.e. stimulates the release of adrenaline). This is the primary benefit of ingesting caffeine.
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Increases fatty acid availability and fuel availability during exercise through activation of the sympathetic nervous system (i.e. direct action of adrenaline). Although this is not a significant contributor to the performance benefits of caffeine.
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Improve contractile performance of the muscle.
On average, caffeine improves cycling power output by ~3% and improves time trial performance by ~2%. Similar benefits can be observed in other endurance sports such as running and swimming. Sprint events such as track cycling events may also see some benefits to caffeine consumption. For example, it has been reported that consuming 5 mg/kg of body weight may improve peak sprint power in a single bout. Interestingly, the benefits of caffeine are wide ranging with decreases in performance also present in some individuals when ingesting caffeine. This highlights the relevance of the varying response of individuals to caffeine use and any other ergogenic aid, in general.
Furthermore, a meta analysis in males ages 20-35 found that caffeine reduced the rating of perceived exertion score by 5.6% and improved overall exercise performance by 11%. This analysis revealed that about 30% of the improvement in exercise improvement can be attributed to the reduction of RPE. In other words, the ability to push the body was improved. Another meta analysis highlights that caffeine does not equally improve the performance outcomes of all individuals.
Most of these benefits stem from caffeine's effects on the central nervous system and its influence (blocking) on adenosine receptors. Within the body, there are many different types of adenosine receptors and the prevalence of these receptors are dependent on the genes of an individual. The genetic variation amongst individuals is thought to be the reason why individuals respond differently to caffeine and as such have varying exercise performance benefits from caffeine.
A large study analyzed the influence of caffeine dose and genetics on cycling time trial performance. This study specifically compared the difference of caffeine response between “fast” and “slow” metabolizers of caffeine. The study found that a moderate dose (4 mg/kg body) provided the greatest improvement (+3%) in time trial performance in all individuals. Interestingly, “fast” metabolizers of caffeine saw benefits at the low caffeine dosage (2 mg/kg body weight) as well. Furthermore, the “fast metabolizer” saw a greater improvement in time trial performance (+6.8%) compared to other studies that used similar dosages (4 mg/kg body). Unfortunately for the “slow” metabolizers, time trial performance on average decreased (-13.7%) at the moderate dosage with no difference observed at the low dosage.
How to use caffeine to improve performance
Dosage
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Taking the appropriate amount of caffeine is critical to reaping the greatest benefits for performance. It has been widely reported that amounts between 3 to 6 milligrams per kg of body weight provides the most consistent improvement to exercise performance, although amounts as low as 2 mg/kg of body weight have also been shown to provide similar improvements.
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The minimal effective dose is still unclear and is variable between individuals. The best is to experiment with different dosages during training to find your sweet spot.
Timing
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Consider taking caffeine 30-90 minutes before exercise. It takes roughly 60 minutes for peak concentration of caffeine to be achieved in the blood. This is helpful for shorter events where ingestion of caffeine mid way through an event is not practical or the event will be over before caffeine has exerted its maximum effect.
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The greatest benefits of caffeine are in states of fatigue as focus and awareness can be greatly improved in a fatigued state. So taking caffeine midway or three-quarters of a way through competition or training may be when the greatest benefits of caffeine can be felt. This can be especially relevant near an end of competition when strategic decisions become increasingly important.
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The maximum benefit of the quoted dosages come from a single bolus. That is, taken all at once. While this is less difficult to achieve before competition, achieving this during competition may pose a challenge.
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Example: during a shorter event (e.g. <75 minutes) that is in the morning, the total caffeine dose can include an individual's morning coffee. This can offset the amount of caffeine required from other sources. For example, if a 70kg person drinks 1-2 cups of coffee before your morning event, then all they would need is one Carbs Fuel 100mg Caffeine Gel prior to the start of the event.
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Example: although not perfect, ingesting caffeine during a 30-90 minute window in the middle or last quarter of competition can still provide benefits. For example, a 70kg person could ingest two to three Carbs Fuel 100mg Caffeine Gels or a bottle with 200-300 mg of caffeine over an hour to help achieve the desired amount.
Format
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Different delivery methods of caffeine can have impacts on how quickly caffeine is able to exert its effects. For example, caffeine capsules can reach peak concentrations more rapidly and achieve greater peak blood concentrations (e.g. in 30 minutes).
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On the other hand, caffeine from drinks, gels, and solids are typically slower in achieving peak concentrations (i.e. 60-120 minutes) in the blood while achieving lower peaks than caffeine capsules.
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Chewing gum can also be used to deliver caffeine and is found to be absorbed more quickly than capsules (<30 minutes). In situations where the effect of caffeine needs to be exerted rapidly, chewing gum may be the best vehicle of delivery.
Other considerations
Anxiety
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If anxiety or nervousness is experienced prior to competition, caffeine may exacerbate these feelings and induce discomfort to certain individuals. As such, consuming caffeine prior to events should be reconsidered.
Sleep
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As described before, caffeine exerts its primary effects through its influence on the central nervous system. As a result, caffeine can negatively impact sleep, especially if it is consumed close to sleep or later in the day. This is a consideration for late-day or multi-day competitions.
Sensitivity and dependence
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If you habitually consume caffeine as part of your daily ritual, continue to do so for training and competition to avoid the negative consequences of withdrawal. Some may seek to elevate the physiological ergogenic effects of caffeine during their target competition and may choose to taper or abstain caffeine ingestion in the lead up to an event so that the benefits are better realized and felt during their competition. However, it has been suggested that the benefits of caffeine ingestion for endurance performance are still realized regardless of habitual caffeine intake.
Hydration
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Caffeine is a diuretic resulting in the increased production of urine. In general, dehydration is not an issue when being consumed in the form of a liquid (e.g. coffee, energy drinks, etc.) as the urine production is offset in the liquid from the beverage. When ingesting caffeine in the form of a capsule, in solids, or gels where fluid content is low or non-existent, it is good practice to ingest fluid to offset the increased production of urine. This will help minimize the potential risk of dehydration.
GI Distress
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While highly variable among individuals, GI distress can occur at moderate and high doses of caffeine, especially those who do not frequently ingest caffeine. This can result in diarrhea and/or nausea. As always, test your dosages during training to avoid catastrophe during competition.
Experimentation
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Given the variable response to caffeine among individuals, we suggest that you experiment and try different dosages and timing of caffeine ingestion to find one that works for you. As always do not attempt this during competition and only during training. Also consider the format of caffeine that you ingest, keeping in mind the time that caffeine needs to achieve peak concentrations in your blood as well as the intensity of the peak. Consider how changing these variables make you feel and select a dosage, delivery method, and timing that works for you.
Health Implications
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Depending on the individual, high caffeine (>6 mg/kg body weight) intake can potentially result in negative cardiovascular conditions such as elevated heart rate, heart palpitations, and increased blood.
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While low doses of caffeine have been found to be safe during pregnancy, it is recommended that moderate and high doses of caffeine be avoided. However, always consult your doctor if you are unsure about the safe dosage for your particular situation.
