In this article, we'll explore the science-backed benefits of caffeine for fitness performance and why it’s the most common ingredient in pre-workout supplements. From increased endurance to enhanced focus, caffeine is more than just a morning pick-me-up; it’s an incredibly well-researched stimulant that can help take your workouts to the next level. 

By Andres Ayesta, MS, RD

Key Points

• Caffeine is a natural stimulant that is commonly found in pre-workout supplements.
• Caffeine has performance-enhancing effects for both aerobic endurance and strength sports, but the results for strength and power are less consistent.
• Besides physical benefits, caffeine improves cognitive function, aiding mental alertness and concentration during workouts.
• Proper timing, dosage, and consideration of individual responses are essential when using caffeine for fitness performance.

Want to take your fitness performance to the next level? If you're a fitness enthusiast or an athlete striving for that extra edge, supplements can give you a boost and help you get more out of each gym session. Today, we’re diving into one of the most thoroughly researched supplements that has broad-ranging effects on athletic performance: caffeine.  

Caffeine is a natural stimulant that acts on the central nervous system, increasing alertness and temporarily preventing fatigue. From increased endurance to enhanced focus, caffeine offers a range of benefits that can elevate your athletic performance [1]. Whether you're a runner aiming to improve your race times or a weightlifter looking to set new personal records, caffeine can support you as you train to reach those goals.

HOW CAFFEINE WORKS

Upon consumption, caffeine quickly crosses the blood-brain barrier. One of its main mechanisms involves interfering with the neurotransmitter adenosine. Normally, adenosine binds with specific receptors in the brain that cause the body to slow down and feel drowsy. However, caffeine has a similar structure to adenosine, so it competes for the receptors [2]. 

By blocking adenosine, caffeine prevents feelings of tiredness. It also leads to increased activity of other neurotransmitters like dopamine and norepinephrine, which promote alertness and a heightened state of awareness. The result is a temporary sense of wakefulness and improved mental clarity [2].

CAFFEINE FOR FITNESS PERFORMANCE

Caffeine's effects extend beyond keeping you awake and focused throughout the day. It also has a number of performance-enhancing effects for both endurance and strength sports that are supported by research.

Aerobic Endurance

Studies have found that caffeine has the most consistent and significant impact on performance for aerobic endurance activities, such as long-distance running, cycling, cross-country skiing, and swimming [3]. Caffeine can delay the onset of fatigue, so you can push yourself harder in your training. The typical dosing that’s found to be effective is 3-6 mg/kg — for a 160-pound (73 kg) person, this works out to about 220 to 440 mg of pre-exercise caffeine, which would be the equivalent of about 2-5 cups of brewed coffee [1].

Because 5 cups of coffee pre-training is not convenient or ideal for most people, a pre-workout supplement which also contains other performance-enhancing ingredients may be the best option for most athletes who want to see an impact on their performance using caffeine. While consuming caffeine in the form of coffee may offer some benefits, it’s not the most practical source [4].

Interestingly, there may be some people who do not see improved performance after taking caffeine. One study found differences in the impact on endurance exercise based on whether someone had a specific variation in a gene related to caffeine metabolism. In this study, 10-km cycling time improved with caffeine supplementation only for those with one specific gene variation [5]. Therefore, it’s important to consider your own personal response to caffeine and monitor its effects. 

Muscular Endurance and Strength

Caffeine has also been found to have benefits for muscular endurance, strength, and power, but the results have been inconsistent. Developing strength and power are common goals of many resistance training programs and are essential for sports such as sprinting, weightlifting, jumping events (e.g., long jump, high jump). Some studies have found that caffeine improves performance both in muscular endurance and muscular strength exercises, but with small effects [1].  While it’s understandable that a dose of caffeine will not immediately add a hundred pounds to your max lifts, small increases in strength expression over time can meaningfully impact strength gains following a training program. 

Power

Power output in exercise refers to how much effort or energy you put into a physical activity in a given amount of time. Essentially, it measures how strong and fast you are at the same time. For example, if you lift a heavy weight quickly, you have a high power output. In studies on performance, it’s often measured with single bouts of sprinting or cycling, or assessing bar velocity during weightlifting. Research studies have reported moderate benefits on power when taking caffeine, yet there have been some mixed findings [1,5]. However, this could be due to the same genetic variation mentioned above. With throwing and jumping movements, caffeine has been found to increase vertical jump height and throwing performance (such as in shot put) [1].

COGNITIVE BENEFITS OF CAFFEINE

Beyond its physical benefits, caffeine has cognitive effects that can improve performance and your workout experience. By increasing mental alertness and concentration, caffeine helps you stay laser-focused on your training goals and maintain peak intensity throughout your session [1]. It’s also possible that increased attention and focus during training could benefit the mind-muscle connection during resistance training. A strong mind-muscle connection can help you target muscles more effectively, with better form and technique. 

Studies have also found potential benefits for reaction time and memory with caffeine supplementation. Furthermore, there are sport-specific benefits of caffeine that have been found in research, including increased rebounds and successful free throws in basketball, increased passing accuracy in soccer, and increased number of successful volleyball actions and decreased the number of imprecise actions within a game [6,7,8]. 

TIMING AND DOSAGE

As with any supplement, timing and dosage are crucial when using caffeine for fitness performance. As mentioned, most studies on caffeine and performance use doses between 3-6 mg/kg. 

Consuming caffeine 30-60 minutes before exercise allows sufficient time for it to reach peak levels in the bloodstream, optimizing its effects during your workout. However, individual responses to caffeine vary, so it's essential to start with lower doses and gradually adjust based on personal tolerance and sensitivity [1].

SIDE EFFECTS?

While caffeine offers an array of performance-enhancing benefits, it's essential to recognize and manage its potential side effects. Consuming caffeine too close to bedtime can disrupt sleep patterns, leading to insomnia and decreased recovery. Additionally, high doses of caffeine that may provide physical benefits to performance also may produce or intensify feelings of anxiety, so it is important to monitor your personal response to caffeine and adjust your habits accordingly. Many people who consume caffeine also experience withdrawal symptoms if they miss a daily dose, which is another factor to consider when deciding whether to supplement with caffeine [1,9].

LIMITATIONS OF CAFFEINE FOR ENERGY 

A final important note about the effects of caffeine is the importance of lifestyle factors on energy and fitness performance. If you're running on empty and need a caffeine kick to get through every training session, there may be other daily habits that should be addressed first, rather than adding more caffeine to get the boost you need.  Caffeine and other pre-workout supplements should not be used as a replacement for 8 hours of sleep each night, taking rest days, and eating enough calories to fuel your body. 

Conclusion

Caffeine is a widely researched supplement that can positively impact many aspects of fitness performance, from aerobic endurance to strength and power. Moreover, its cognitive benefits, such as increased focus and alertness, can help with sport performance and support an effective gym session. However, individual responses to caffeine can vary, and it's crucial to find the right timing and dosage that works best for you. Additionally, it's essential to be mindful of potential side effects and avoid excessive reliance on caffeine, ensuring that lifestyle factors like sleep and nutrition are prioritized for overall energy and well-being. Remember, consistency in training and a balanced lifestyle are the foundations of success, with caffeine as an added bonus to amplify your efforts in the gym.

About the Author

Andres Ayesta is a sports dietitian and the founder of Planos Nutrition, with over 12 years of experience helping people transform their nutrition and lifestyle. He works with busy professionals and parents to help them lose weight, improve their confidence, and show up as the best version of themselves, using a personalized, evidence-based nutrition blueprint.

With a bachelor's degree in Nutrition and Dietetics from the University of Southern Indiana and a master's degree in Exercise Science and Sports Nutrition from the University of Central Florida, Andres has earned numerous certifications, including Certified Strength and Conditioning Coach (CSCS) and Certified Specialist in Sports Dietetics (CSSD). He is a licensed Registered Dietitian in the state of Florida and provides coaching programs worldwide. To connect with Andres, you can find him on TikTok @andresthedietitian or Instagram @andresayesta

References:

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2. Fiani B, Zhu L, Musch BL, Briceno S, Andel R, Sadeq N, Ansari AZ. The neurophysiology of caffeine as a central nervous system stimulant and the resultant effects on cognitive function. Cureus. 2021 May 14;13(5). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8202818/

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8. Perez-Lopez A, Salinero JJ, Abian-Vicen J, Valades D, Lara B, Hernandez C, Areces F, Gonzalez C, Del Coso J. Caffeinated energy drinks improve volleyball performance in elite female players. Med Sci Sports Exerc. 2015 Apr 1;47(4):850-6. https://journals.lww.com/acsm-msse/Fulltext/2015/04000/Caffeinated_Energy_Drinks_Improve_Volleyball.23.aspx

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