All About Caffeine

Author: Akshita Arora,INFS faculty 

 

Caffeine and coffee: which out of the two is better for sports performance?
We humans have a very long history of consuming caffeine and caffeinated beverages. It is the most extensively used drug all over the world and is commonly used by athletes to aid their performance. Caffeine has shown to increase sports performance and has shown various effects on the endocrine system as well as substrate utilization. Many people believe that ingesting the same amount of caffeine via food source is as effective as ingesting caffeine in supplemental form. However, you cannot extrapolate the results of caffeine on coffee since coffee is not just caffeine. Coffee contains hundreds, if not thousands, of biologically active compounds, which have so many health benefits over just caffeine. Similarly, even for equated amount of caffeine, coffee may present lesser bio-availability of caffeine than caffeine alone since some of these biologically active compounds must be pharmacodynamically active and may therefore counteract some of the effects of caffeine. Hence, the results of the studies done on coffee cannot be extrapolated to caffeine. They are different. A study exactly highlights this. This study examined the effect of coffee and caffeine for equated caffeine dosage (4.45mg/kg of body mass) on endurance performance. In this study, nine healthy, fit, young adults performed five trials after ingesting either: anhydrous caffeine capsule, regular coffee, decaffeinated coffee, decaffeinated coffee with added caffeine or placebo. After 1 hour of rest, subjects ran “to voluntary exhaustion” on the treadmill at a power output equivalent to ~85% of VO2max. Six subjects had their longest run of all five trials after ingestion of caffeine capsules, the ingestion of coffee in any form (regular, decaffeinated or decaf with added caffeine) did not enhance endurance in the study more than the placebo. Thus it appears that some component(s) in coffee interfere with the normal ergogenic response of coffee.
Although this study showed benefits of caffeine over coffee, there are some studies which show no significant difference.
One research studied the effects of coffee and caffeine anhydrous on strength and sprint performance on 54 resistance- trained males. They completed baseline strength testing which consisted of both 1RM and repetitions till fatigue for leg press and bench press followed by strength testing for sprinting on a friction-loaded ergometer. After 48 hrs, participants returned for post-testing and ingested either 300 mg caffeine (CAF), caffeine matched dosage of coffee (COF) or a flavored placebo (PLA) 30 minutes before exercise. Results did show significant improvement in strength outcomes of CAF and COF. Repeated sprint results also showed similar attenuated power reductions in both CAF and COF groups.
Data from several studies suggests that 3-6mg/kg of body mass is an optimal dosage for caffeine. But whether to ingest that amount through coffee or caffeine depends upon several factors such as:
1. Caffeine in coffee depends on the bean origin, level of roast and extraction and grind method. It can vary from brand to brand, product to product.
2. Taking same amount of caffeine from coffee is difficult that taking it from a supplemental form.
3. Some people develop GI issue with coffee. Heartburn is the most frequently reported symptom after coffee drinking, but the same symptoms are not observed when they use caffeine supplements.
4. Considering the potential health benefits associated with regular coffee consumption, low cost and easy availability of coffee, it cannot be disregarded as an effective source of pre-exercise caffeine. Roasted coffee beans also contain chemicals called cholinomimetics that are minor stimulants, but can also suppress hunger. Note that this effect is not observed with supplemental caffeine. This means if you are going to follow Intermittent Fasting (IF) post workout, coffee is definitely a better choice.

How caffeine affects the performance?
The history of caffeine is almost as old as mankind and today it’s one of the most commonly used performance improvement aid. It is one of the main ingredients in almost all pre-workout drinks. Even red bull claims to give you wings because of its high caffeine content (P.S I am not promoting any brand) yet surprisingly the primary mechanism by which caffeine exerts its effect is still unclear. What makes caffeine so special? We will discuss different theories and studies behind them.
1. Glycogen Sparing:
Most popular theory that talks about ergogenic effects and mechanism of caffeine is that caffeine increase fat oxidation and spares muscle glycogen. Caffeine increases adrenaline level and antagonizes adenosine receptors which can effectively enhance lipolysis and therefore the availability of Free fatty acids(FFAs) in the blood stream. Thus fat oxidation can go up, and hence sparing the muscle glycogen, which is responsible for fueling your workouts.
However, successive studies failed to prove that caffeine has any muscle glycogen sparing effect or any significant role in fat oxidation.
2. Increased motor unit recruitment:
A study suggests that caffeine may work, in part, by creating a more favorable intracellular ionic environment in active muscle which could facilitate force production by each motor unit.
3. Effect on Central Nervous System (CNS):
Another study discusses various mechanisms of caffeine on central nervous system (CNS):
A. Mobilization of intracellular calcium that prolongs the duration of muscle contraction and inhibition ofspecific phosphodiesterases that potentiates the effects of substances such as catecholamines. But these mechanisms are shown to take place at non physiological dosage of caffeine.
B. Antagonism at the level of adenosine receptors that increases energy metabolism in brain but causes decrease in cerebral blood flow at the same time.
This mechanism of stimulation of CNS by caffeine was also studied in another research. It discussed the antagonist action of caffeine on adenosine receptors which inhibit the negative effects of neurotransmission. This could have favourable effects on negating decreased firing rates and produce a more sustainable and forceful muscle contraction.
4. Effect on Sympathetic Nervous System (SNS):
Caffeine blocks adenosine receptors, hence enhancing Sympathetic Nervous system. This inhibition of adenosine receptors leads to increase in free adenosine, thus increasing blood flow to muscles and leading to faster removal of waste and inflammatory substance. Thus, this leads to reduced feeling of pain and soreness and can result in better muscle output.

So, we found that although the main mechanism behind the ergogenic effects of caffeine is still unclear, but we know that caffeine is beneficial. As discussed above, data from several studies suggest that 3-6 mg/kg of body mass is an optimal dosage range. Caffeine is rapidly absorbed in body and reaches its maximum plasma concentration in 1 hour but it varies from person to person. Hence, take your caffeine 30-90 mins prior to your workout. See what works best for you. Its half cycle is of 4-6 hours. Hence it is generally recommended to not to take caffeine 4-6 hours prior to sleeping.

Caffeine Habituation: Do you need to cycle caffeine for enhanced performance?
It’s a common belief that ergogenic effects of caffeine are decreased as you develop habituation towards caffeine. As we learnt in part 2, we still don’t know the exact mechanism by which caffeine shows its ergogenic benefits, similarly we don’t know exactly how we develop habituation and how does it affect your performance.
To analyze this, let’s have a look at some of the researches which studied this effect of caffeine habituation on sports performance.
One study compared effect of caffeine consumption on VO2 max and the anaerobic threshold in caffeine naïve and habituated users. The study found no effect on VO2 max or anaerobic threshold from a caffeine supplement in habitual and caffeine naïve participants. While resting metabolism and ventilation, as well as resting and exercise plasma free fatty acid (FFA) increased in the caffeine naïve group, this did not affect performance outcomes.
Another study examined the effect of ingesting 6mg/kg of body mass of caffeine on multiple sprint running ability test with male and female participants who were either habitual caffeine consumers or caffeine naïve. Participants consisted of 6 males, 4 female caffeine naïve and 3 males, 5 female habituated users. Study found no significant difference in the individual sprint times with caffeine ingestion between caffeine naïve and habitual caffeine consuming participants.
One more study examined the effect of ingesting either 6mg/kg of body mass of caffeine or placebo or no supplement on cycling time trials. Participant consisted of forty endurance-trained cyclists were allocated into tertiles according to their daily caffeine intake: low (58 ± 29 mg.d-1), moderate (143 ± 25 mg.d-1), and high consumers (351 ± 139 mg.d-1). The study concluded that the performance effects of acute caffeine supplementation were not influenced by the level of habitual caffeine consumption.
Several researches indicate that caffeine habituation does not result in decrease in sports performance. Hence, there is absolutely no need to cycle caffeine.
But there was a limitation:
All the researches examined the effect of caffeine habituation on endurance exercises. There is no data available (as much we know) to study this effect on strength training but we speculate that results should not be any different.

References:
1. Graham, T. E., Hibbert, E., & Sathasivam, P. (1998). Metabolic and exercise endurance effects of coffee and caffeine ingestion. Journal of Applied Physiology, 85(3), 883-889.
2. Trexler, E. T., Smith-Ryan, A. E., Roelofs, E. J., Hirsch, K. R., & Mock, M. G. (2016). Effects of coffee and caffeine anhydrous on strength and sprint performance. European journal of sport science, 16(6), 702-710.
3. Ribeiro, J. A., & Sebastiao, A. M. (2010). Caffeine and adenosine. Journal of Alzheimer’s Disease, 20(S1), 3-15.
4. Costill, D. L., Dalsky, G. P., & Fink, W. J. (1978). Effects of caffeine ingestion on metabolism and exercise performance. Medicine and science in sports, 10(3), 155-158.
5. Graham, T. E., Helge, J. W., MacLean, D. A., Kiens, B., & Richter, E. A. (2000). Caffeine ingestion does not alter carbohydrate or fat metabolism in human skeletal muscle during exercise. The Journal of Physiology, 529(3), 837-847.
6. Graham, T. E. (2001). Caffeine and exercise. Sports medicine, 31(11), 785-807.
7. Nehlig, A., Daval, J. L., & Debry, G. (1992). Caffeine and the central nervous system: mechanisms of action, biochemical, metabolic and psychostimulant effects. Brain Research Reviews, 17(2), 139-170.
8. Hurley, C. F., Hatfield, D. L., & Riebe, D. A. (2013). The effect of caffeine ingestion on delayed onset muscle soreness. The Journal of Strength & Conditioning Research, 27(11), 3101-3109.
9. Dodd, S. L., Brooks, E., Powers, S. K., & Tulley, R. (1991). The effects of caffeine on graded exercise performance in caffeine naive versus habituated subjects. European journal of applied physiology and occupational physiology, 62(6), 424-429.
10. Jordan, J. B., Farley, R. S., & Caputo, J. L. (2012). Caffeine and sprint performance in habitual and caffeine naïve participants. International Journal of Exercise Science, 5(1), 6.
11. de Souza Gonçalves, L., de Salles Painelli, V., Yamaguchi, G., de Oliveira, L. F., Saunders, B., da Silva, R. P., … & Gualano, B. (2017). Dispelling the myth that habitual caffeine consumption influences the performance response to acute caffeine supplementation. Journal of Applied Physiology, jap-00260.

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