Hi guys, how are you? Today I, Gabi, will tell you a little more about the relationship between caffeine and physical exercise - which is more than proven!

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Caffeine is the most consumed psychoactive substance in the world and is naturally present in dozens of plant species, including coffee, herbs and cocoa. Caffeine and its health effects have been a long-studied topic and continue to be a dietary compound of public health concern, as indicated by extensive investigations. At the same time, caffeine has become ubiquitous in the sporting world, where there is great interest in better understanding the impact of caffeine on exercise performance.

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Although the action of caffeine on the central nervous system (CNS) is widely accepted as the primary mechanism by which caffeine alters performance, several mechanisms have been proposed to explain the ergogenic effects of caffeine, including increased myofibrillar calcium availability, optimized metabolism of exercise and substrate availability, as well as CNS stimulation.

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Caffeine also appears to have some direct effects on muscle that may contribute to its ergogenicity. The most likely route by which caffeine can benefit muscle contraction is through the mobilization of calcium ions (Ca2+), which facilitates the production of force by each motor unit. Fatigue caused by the gradual reduction in Ca2+ release after exercise can be alleviated after ingesting caffeine. Similarly, caffeine may work, in part, in the periphery by increasing sodium/potassium (Na+/K+) pump activity to potentially increase the excitation-contraction coupling necessary for muscle contraction.

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Caffeine appears to exert its effects at multiple sites in the body, but the most robust evidence suggests that the primary target is the CNS, which is now widely accepted as the primary mechanism by which caffeine alters mental and physical performance. Caffeine is believed to exert its effects on the CNS through antagonism of adenosine receptors, leading to increases in neurotransmitter release, motor unit firing rates, and pain suppression.

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Adenosine is involved in numerous processes and pathways, and plays a crucial role as a homeostatic regulator and neuromodulator in the nervous system. The main known effects of adenosine are to decrease the concentration of CNS neurotransmitters, including serotonin, dopamine, acetylcholine, norepinephrine and glutamate. Caffeine, which has a molecular structure similar to adenosine, binds to adenosine receptors after ingestion and therefore increases the concentration of these neurotransmitters. This results in positive effects on mood, alertness, focus, and alertness in most, but not all, individuals.

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After critical evaluation of the literature available to date, the position of the International Society of Sports Nutrition (ISSN) regarding caffeine intake is as follows:

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1. Caffeine supplementation has been shown to improve various aspects of exercise performance in many, but not all studies. Small to moderate benefits of caffeine use include, but are not limited to: muscular endurance, speed of movement and muscular strength, running, jumping and throwing performance, as well as a wide range of sport-specific aerobic and anaerobic actions.

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2. Aerobic endurance appears to be the form of exercise with the most consistent moderate to large benefit from caffeine use, although the magnitude of its effects differs between individuals.

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3. Caffeine has been consistently shown to improve exercise performance when consumed in doses of 3 to 6 mg/kg of body mass. Very high doses of caffeine (e.g., 9 mg/kg) are associated with a high incidence of side effects and do not appear to be necessary to elicit an ergogenic effect.

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4. The most commonly used time for caffeine supplementation is 60 minutes before exercise. The ideal timing of caffeine intake likely depends on the source of caffeine. For example, compared to caffeine capsules, caffeinated gummies may require a shorter wait time from consumption to the start of your workout.

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5. Caffeine appears to improve physical performance in both trained and untrained individuals.

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6. Interindividual differences in sports and exercise performance, as well as adverse effects on sleep or feelings of anxiety following caffeine ingestion, may be attributed to genetic variation associated with caffeine metabolism and physical and psychological response. Other factors, such as habitual caffeine intake, may also play a role in variation in response between individuals.

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7. Caffeine has been shown to be ergogenic for cognitive function, including attention and alertness, in most individuals.

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8. Caffeine may improve cognitive and physical performance in some individuals under sleep-deprived conditions.

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9. The use of caffeine in conjunction with resistance exercise in heat and altitude is well supported when dosages range from 3 to 6 mg/kg and 4 to 6 mg/kg, respectively.

10. Alternative sources of caffeine such as caffeine chewing gum, energy gels and gummies have been shown to improve performance, particularly in aerobic exercise.

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11. Energy drinks and pre-workout supplements containing caffeine have been shown to improve anaerobic and aerobic performance.

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In summary, caffeine supplementation has been shown to improve many aspects of exercise, including prolonged aerobic activities and short-duration, high-intensity exercise. Caffeine in recommended doses does not appear to significantly influence hydration. Individuals should also be aware of side effects associated with caffeine intake, such as sleep disturbances and anxiety, which are often linearly dose dependent.

 

Kisses and until next time,

Gabi.

Reference: Guest NS, VanDusseldorp TA, Nelson MT, Grgic J, Schoenfeld BJ, Jenkins NDM, Arent SM, Antonio J, Stout JR, Trexler ET, Smith-Ryan AE, Goldstein ER, Kalman DS, Campbell BI. International society of sports nutrition position stand: caffeine and exercise performance. J Int Soc Sports Nutr. 2021 Jan 2;18(1):1. doi: 10.1186/s12970-020-00383-4. PMID: 33388079; PMCID: PMC7777221.