Caffeine is a highly consumed substance naturally found in various plants' beans, fruits, and leaves, such as coffee beans, tea leaves, cacao pods, and kola nuts. It can also be added synthetically to energy drinks and over-the-counter medicines. Ninety percent of adults drink caffeine, which increases energy by stimulating the central nervous system and promoting awareness. Consequently, it has been demonstrated to enhance athletic performance in a number of ways, including by changing how pain and exertion are perceived.
Numerous foods and products, such as energy drinks, supplements, gels, chews, and medications, contain caffeine.
Caffeine improves performance in a number of ways, such as by stimulating the central and peripheral nervous systems and raising the availability of calcium ions in the muscles.
Caffeine counteracts the effects of adenosine, a compound that induces tiredness and sleepiness. By attaching itself to adenosine receptors, it reduces the effects of adenosine while increasing wakefulness and alertness.
Caffeine side effects can include headaches, anxiety, insomnia, dizziness, and dehydration in certain individuals. For this reason, it is crucial to speak with a sports dietitian before consuming caffeine for athletic performance.
Read more to learn about how caffeine and performance are related.
How does caffeine enhance performance?
Through stimulation of the central and peripheral nervous systems, caffeine improves performance and may have an impact on pain and perceived exertion.
Adenosine is a compound that gradually increases throughout the day. Adenosine molecules bind adenosine receptors, causing tiredness and sleepiness. Sleep and wakefulness cycles are regulated by the brain's natural production of adenosine. Nevertheless, caffeine functions similarly to adenosine and binds to adenosine receptors, but it has the opposite effect, making you awake and alert.
Caffeine increases neurotransmitters such as dopamine, serotonin, acetylcholine, norepinephrine, and glutamate, contributing to increased focus, alertness, vigilance, and improved mood.
Additionally, caffeine has a direct impact on the skeleton. It is believed to improve the concentration or availability of calcium ions (Ca2+) in the myofibrils that power muscle contraction. Muscle at rest has a relatively low concentration of Ca2+; when it is activated, it releases Ca2+, which binds to certain proteins and causes the muscle to contract.
As a result, increased availability of calcium helps the muscle regain its strength and return to the level it had before it got tired. When the caffeine wears off, accumulating adenosine binds to its receptors, causing tiredness, often called a 'caffeine crash.'
When to consume caffeine?
In professional sports, minor improvements can have a significant impact, as even a split-second difference can affect medal rankings. Caffeine is one of the most widely used sports supplements that can improve performance, which is why athletes use them so frequently.
Caffeine has been shown to have beneficial effects on:
- Endurance sports. Endurance sports, such as middle- and long-distance running and cycling. Caffeine has been shown to enhance endurance by 2–4% at doses of 3–6 mg per kg of body mass.
- Muscular strength and power. Caffeine has been shown to enhance muscular strength by 2–7%, which can be significant for powerlifting and weightlifting athletes.
- Repeated sprint performance. Studies have demonstrated the advantages of interval training, including intermittent sprinting. According to a study, sprint performance was enhanced when there was a 90-second rest interval but not when there was a 20-second rest interval. Consequently, depending on the amount of rest in between intervals, caffeine's effects on repeated-sprint performance may vary, and more study is required to fully understand the effects.
- Pre-training energy boost if you are carrying fatigue into a session. Caffeine can provide a pre-training energy boost to overcome tiredness and maximize performance.
What is an effective dose of caffeine?
It has been demonstrated that doses of 3 to 6 mg per kg body mass enhance exercise performance. When doses exceed 9 mg/kg body mass, side effects are frequently experienced. Therefore, 210 mg of caffeine is expected to enhance the performance of a 70 kg athlete.
But the effects are very individualistic and affected by many factors, including genetics, habitual caffeine intake, caffeine timing, training status, and environmental influences.
Is timing important?
You can consume caffeine before, during, or after working out. It is usually taken 60 minutes prior to working out. However, the optimal timing of caffeine use can change based on the sport.
The best time to consume caffeine also depends on its source. Caffeine-chewing gums are absorbed quicker than caffeine capsules.
Caffeine-containing sports nutrition products
Caffeine can be taken naturally from foods or synthetic caffeine sources such as over-the-counter medications, energy drinks, pre-workout supplements, and sports foods such as gel, and they contain various amounts of caffeine.
A few examples of products that contain caffeine are:
- Energy drinks. Energy drinks like Red Bull and Monster typically contain caffeine as their main ingredient. Both Red Bull and Monster have 160 mg of caffeine per 500 mL.
- Pre-workout supplements. They contain various ingredients, including caffeine, to boost energy before exercise. Caffeine content differs between products but generally ranges from 90 to 400 mg per serving.
- Energy gels. Some energy gels, especially the ones designed for endurance sports such as running and cycling, contain caffeine. Caffeine in gels ranges from 10 to 100 mg per serving.
- Energy chews. Energy chews often include caffeine for quick energy during physical activity.
- Sports nutrition bars. Some protein bars and energy bars may contain caffeine.
- Caffeinated water. There are also products like caffeinated water, which are produced to provide hydration with added caffeine.
- Fat-loss supplements. Fat burners and weight loss products may contain 50 to 150 mg of caffeine per serving.
- Sports drinks. Some sports drinks may include caffeine for energy and endurance benefits.
- Over-the-counter medications. Caffeine-containing over-the-counter medications are available and used by some athletes. No-doz, one of the over-the-counter caffeine medications, contains 100 mg of caffeine per tablet.
There are also various foods that also contain caffeine, including:
- Chocolate: 5–50 mg caffeine (1 bar/60 g)
- Coke: 36 mg.
- Brewed coffee: 80–280 mg
- Tea: 25–110 mg
*The values of caffeine content are taken from the Australian Sports Institute fact sheet on sports supplement framework on caffeine.
Downsides of caffeine
Mental health problems are not rare in elite athletes; they're as common as 50%. Certain athletes may be more susceptible to the effects of caffeine (due to genetic variations), which means that even small amounts of caffeine can cause anxiety and trouble sleeping. However, 400 mg or less of caffeine is considered safe for adults except for pregnant women.
Consuming too much caffeine can cause symptoms including:
Pure or highly concentrated forms of caffeine can even be fatal.
Note that some products (like pre-workout or fat-loss supplements) that contain caffeine might also contain illegal substances.
Although studies have shown that caffeine improves sports performance, each individual's experience with the drug can differ greatly. As such, adding caffeine to a sports nutrition program for an athlete usually takes some trial and error. To optimize the effects of caffeine, speak with your coach and sports dietitian before using it to improve your performance in sports.
- Australian Institute of Sport. AIS SPORTS SUPPLEMENT FRAMEWORK CAFFEINE.
- Journal of the International Society of Sports Nutrition. International society of sports nutrition position stand: caffeine and exercise performance.
- Australian Institute of Sport. AIS SPORTS SUPPLEMENT FRAMEWORK CAFFEINE GROUP A.
- British Journal of Sports Medicine. Wake up and smell the coffee: caffeine supplementation and exercise performance—an umbrella review of 21 published meta-analyses.
- MedlinePlus. Caffeine.