Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit. Abstract Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids.

Publication types Research Support, Non-U. Gov't Review. Substances Central Nervous System Stimulants Caffeine. In , Battram et al. It was postulated that the fractions respond differently to the recovery phase of exercise and thus glycogen resynthesis.

Following exercise and throughout the 5-hr recovery period subjects consumed in total g of exogenous carbohydrate. Muscle biopsies and blood samples revealed caffeine ingestion did not obstruct proglycogen or macroglycogen resynthesis following exhaustive, glycogen depleting exercise [ 66 ].

It is imperative to recognize that each person may respond differently to supplements and compounds containing caffeine. An individual at rest, and even sedentary in nature, is likely to have a different response compared to a trained, conditioned athlete, or physically active person.

According to the data presented by Battram et al. In a more recent study, Pedersen et al. The data presented in these studies [ 66 , 67 ] indicate that caffeine is not detrimental to glycogen repletion, and in combination with exogenous carbohydrate may actually act to enhance synthesis in the recovery phase of exercise.

From a practical standpoint, however, it should be considered that most athletes or recreationally trained individuals would choose to supplement with caffeine prior to competition for the purpose of enhancing performance.

Moreover, clearance of caffeine in the bloodstream occurs between 3 and 6 hours, and may extend beyond that time point depending on the individual. Therefore, caffeine consumption pre- and post-exercise would have to be precisely timed so as not to interrupt sleep patterns of the athlete, which in itself could negatively affect overall recovery.

Various methods of caffeine supplementation have been explored and results have provided considerable insight into appropriate form and dosage of the compound. One of the most acknowledged studies, published by Graham et al.

Caffeine in capsule form significantly increased work capacity allowing them to run an additional km [ 26 ], as compared to the four other treatments. It was also proposed by Graham and colleagues [ 26 ] that perhaps other indistinguishable compounds within coffee rendered caffeine less effective than when consumed in anhydrous form.

This suggestion was supported by de Paulis et al. In turn, these derivatives may have the potential for altering the affects of caffeine as an adenosine antagonist, possibly reducing the drug's ability to diminish the inhibitory action of adenosine [ 68 ].

As such, McLellan and Bell [ 27 ] examined whether a morning cup of coffee just prior to anhydrous caffeine supplementation would have any negative impact on the compound's ergogenic effect. Subjects were physically active and considered to be moderate-to-high daily consumers of caffeine.

Subjects consumed one cup of coffee with a caffeine dosage that was approximately 1. The results indicated caffeine supplementation significantly increased exercise time to exhaustion regardless of whether caffeine in anhydrous form was consumed after a cup of regular or decaffeinated coffee [ 27 ].

While caffeine supplemented from a cup of coffee might be less effective than when consumed in anhydrous form, coffee consumption prior to anhydrous supplementation does not interfere with the ergogenic effect provided from low to moderate dosages. Wiles et al.

This form and dose was used to mimic the real life habits of an athlete prior to competition. Subjects performed a m treadmill time trial. Ten subjects with a VO 2max of In addition, six subjects also completed a third protocol to investigate the effect of caffeinated coffee on sustained high-intensity exercise.

Results indicated a 4. For the "final burst" simulation, all 10 subjects achieved significantly faster run speeds following ingestion of caffeinated coffee. Finally, during the sustained high-intensity effort, eight of ten subjects had increased VO 2 values [ 69 ]. In a more recent publication, Demura et al.

Subjects consumed either caffeinated or decaffeinated coffee 60 min prior to exercise. The only significant finding was a decreased RPE for the caffeinated coffee as compared to the decaffeinated treatment [ 70 ]. Coffee contains multiple biologically active compounds; however, it is unknown if these compounds are of benefit to human performance [ 71 ].

However, it is apparent that consuming an anhydrous form of caffeine, as compared to coffee, prior to athletic competition would be more advantageous for enhancing sport performance.

Nevertheless, the form of supplementation is not the only factor to consider as appropriate dosage is also a necessary variable. Pasman and colleagues [ 28 ] examined the effect of varying quantities of caffeine on endurance performance. Results were conclusive in that all three caffeine treatments significantly increased endurance performance as compared to placebo.

Moreover, there was no statistical difference between caffeine trials. Navy SEAL training study published by Lieberman et al [ 40 ].

Results from that paper indicated no statistical advantage for consuming an absolute dose of mg, as opposed to mg. However, the mg dose did result in significant improvements in performance, as compared to mg, and mg was at no point statistically different or more advantageous for performance than placebo [ 40 ].

In response to why a low and moderate dose of caffeine significantly enhanced performance, as compared to a high dose, Graham and Spriet [ 8 ] suggested that, "On the basis of subjective reports of some subjects it would appear that at that high dose the caffeine may have stimulated the central nervous system to the point at which the usually positive ergogenic responses were overridden".

This is a very pertinent issue in that with all sports nutrition great individuality exists between athletes, such as level of training, habituation to caffeine, and mode of exercise. Therefore, these variables should be considered when incorporating caffeine supplementation into an athlete's training program.

Results were comparable in a separate Spriet et al. publication [ 18 ]. Once again, following caffeine supplementation times to exhaustion were significantly increased. Results indicated subjects were able to cycle for 96 min during the caffeine trial, as compared to 75 min for placebo [ 18 ].

Recently McNaughton et al. This investigation is unique to the research because, while continuous, the protocol also included a number of hill simulations to best represent the maximal work undertaken by a cyclist during daily training.

The caffeine condition resulted in the cyclists riding significantly further during the hour-long time trial, as compared to placebo and control. The use of caffeine in anhydrous form, as compared to a cup of caffeinated coffee, seems to be of greater benefit for the purpose of enhancing endurance performance.

It is evident that caffeine supplementation provides an ergogenic response for sustained aerobic efforts in moderate-to-highly trained endurance athletes. The research is more varied, however, when pertaining to bursts of high-intensity maximal efforts. Collomp et al. Compared to a placebo, caffeine did not result in any significant increase in performance for peak power or total work performed [ 46 ].

As previously stated, Crowe et al. Finally, Lorino et al. Results were conclusive in that non-trained males did not significantly perform better for either the pro-agility run or s Wingate test [ 73 ]. In contrast, a study published by Woolf et al. It is exceedingly apparent that caffeine is not effective for non-trained individuals participating in high-intensity exercise.

This may be due to the high variability in performance that is typical for untrained subjects. Results, however, are strikingly different for highly-trained athletes consuming moderate doses of caffeine.

Swimmers participated in two maximal m freestyle swims; significant increases in swim velocity were only recorded for the trained swimmers. Results indicated a significant improvement in swim times for those subjects who consumed caffeine, as compared to placebo. Moreover, time was measured at m splits, which resulted in significantly faster times for each of the three splits for the caffeine condition [ 74 ].

As suggested by Collomp et al. Participants in a study published by Woolf et al. A recent study published by Glaister et al. Subjects were defined as physically active trained men and performed 12 × 30 m sprints at 35 s intervals. Results indicated a significant improvement in sprint time for the first three sprints, with a consequential increase in fatigue for the caffeine condition [ 31 ].

The authors suggested that the increase in fatigue was due to the enhanced ergogenic response of the caffeine in the beginning stages of the protocol and, therefore, was not meant to be interpreted as a potential negative response to the supplement [ 31 ].

Bruce et al. Results of the study revealed an increase in performance for both time trial completion and average power output for caffeine, as compared to placebo mg glucose.

Time trial completion improved by 1. Anderson and colleagues [ 75 ] tested these same doses of caffeine in competitively trained oarswomen, who also performed a 2,m row. Team sport performance, such as soccer or field hockey, involves a period of prolonged duration with intermittent bouts of high-intensity playing time.

As such, Stuart et al. Subjects participated in circuits that were designed to simulate the actions of a rugby player, which included sprinting and ball passing, and each activity took an average seconds to complete. In total, the circuits were designed to represent the time it takes to complete two halves of a game, with a 10 min rest period.

An improvement in ball passing accuracy is applicable to a real-life setting as it is necessary to pass the ball both rapidly and accurately under high-pressure conditions [ 33 ]. This study [ 33 ] was the first to show an improvement in a team sport skill-related task as it relates to caffeine supplementation.

Results of this study [ 33 ] also indicated that for the caffeine condition subjects were able to maintain sprint times at the end of the circuit, relative to the beginning of the protocol. Schneiker et al. Ten male recreationally competitive team sport athletes took part in an intermittent-sprint test lasting approximately 80 minutes in duration.

Specifically, total sprint work was 8. The training and conditioning of these athletes may result in specific physiologic adaptations which, in combination with caffeine supplementation, may lead to performance enhancement, or the variability in performance of untrained subjects may mask the effect of the caffeine.

In the area of caffeine supplementation, strength research is still emerging and results of published studies are varied. The protocol consisted of a leg press, chest press, and Wingate. The leg and chest press consisted of repetitions to failure i.

Results indicated a significant increase in performance for the chest press and peak power on the Wingate, but no statistically significant advantage was reported for the leg press, average power, minimum power, or percent decrement [ 30 ].

Beck et al. Resistance trained males consumed caffeine mg, equivalent to 2. Participants were also tested for peak and mean power by performing two Wingate tests separated by four minutes of rest pedaling against zero resistance.

A low dose of 2. Significant changes in performance enhancement were not found for lower body strength in either the 1RM or muscular endurance [ 35 ]. Results of the Beck et al. Findings from Astorino and colleagues [ 76 ] revealed no significant increase for those subjects supplemented with caffeine for either bench or leg press 1RM.

Astorino et al. The Beck et al. design included a 2. Indeed it is possible that the degree of intensity between the two protocols could in some way be a resulting factor in the outcome of the two studies.

Participants in this investigation [ 77 ] were considered non-habituated to caffeine and consumed much less than 50 mg per day.

Research on the effects of caffeine in strength-power sports or activities, while varied in results and design, suggest that supplementation may help trained strength and power athletes. Of particular interest, is the lack of significant finding for lower body strength as compared to upper body performance.

Research investigations that have examined the role of caffeine supplementation in endurance, high-intensity, or strength-trained women is scant, especially in comparison to publications that have investigated these dynamics in men.

Motl et al. Moreover, there was no statistically significant difference between the 5 and 10 mg dose [ 78 ].

The lack of a dose-dependent effect is in line with previously published investigations [ 8 , 28 , 32 , 40 ]. In two different publications, Ahrens and colleagues [ 79 , 80 ] examined the effects of caffeine supplementation on aerobic exercise in women.

In one study [ 79 ] recreationally active women not habituated to caffeine participated in moderately-paced 3. From a research standpoint the increase in VO 2 0.

Finally, no significant results were reported for caffeine and aerobic dance bench stepping [ 80 ]. Goldstein and colleagues [ 81 ] examined the effects of caffeine on strength and muscular endurance in resistance-trained females.

Similar to results reported by Beck et al. The research pertaining exclusively to women is somewhat limited and exceptionally varied.

Publications range from examining caffeine and competitive oarswomen [ 75 ] to others that have investigated recreationally active individuals performing moderate-intensity aerobic exercise [ 79 , 80 ].

Taken together, these results indicate that a moderate dose of caffeine may be effective for increasing performance in both trained and moderately active females. Additional research is needed at all levels of sport to determine if caffeine is indeed effective for enhancing performance in women, either in a competitive or recreationally active setting.

It is standard procedure for a research protocol to account for the daily caffeine intake of all subjects included within a particular study.

The purpose of accounting for this type of dietary information is to determine if caffeine consumption a. has an effect on performance and b. if this outcome is different between a person who does or does not consume caffeine on a regular basis.

Results demonstrated an enhancement in performance for both groups; however, the treatment effect lasted approximately three hours longer for those persons identified as nonusers [ 41 ]. Dodd et al. The only reported differences, such as ventilation and heart rate, were at rest for those persons not habituated to caffeine [ 82 ].

Van Soeren et al. Finally, it was suggested by Wiles et al. What may be important to consider is how caffeine affects users and nonusers individually. Thirteen of 22 subjects in that investigation described feelings of greater energy, elevated heart rate, restlessness, and tremor.

It should also be noted that these feelings were enhanced in participants who consumed little caffeine on a daily basis [ 76 ]. It would seem the important factor to consider is the individual habits of the athlete and how caffeine supplementation would affect their personal ability to perform.

It has been widely suggested that caffeine consumption induces an acute state of dehydration. However, consuming caffeine at rest and during exercise presents two entirely different scenarios.

Specifically, studies examining the effects of caffeine-induced diuresis at rest can and should not be applied to athletic performance.

In a review publication on caffeine and fluid balance, it was suggested by Maughan and Griffin [ 85 ] that "hydration status of the individual at the time of caffeine ingestion may also affect the response, but this has not been controlled in many of the published studies".

Despite the unfounded, but accepted, notion that caffeine ingestion may negatively alter fluid balance during exercise, Falk and colleagues [ 86 ] found no differences in total water loss or sweat rate following consumption of a 7.

The authors did caution that exercise was carried out in a thermoneutral environment and additional research is warranted to determine effects in a more stressful environmental condition [ 86 ]. Wemple et al. In total, 8. Results indicated a significant increase in urine volume for caffeine at rest, but there was no significant difference in fluid balance for caffeine during exercise [ 87 ].

These results are noteworthy, because according to a review published by Armstrong [ 88 ], several research studies published between and reported outcome measures, such as loss of water and electrolytes, based on urine samples taken at rest and within hours of supplementation [ 88 ].

Kovacs and colleagues [ 56 ] published similar results in a study that examined time trial performance and caffeine consumption in various dosages added to a carbohydrate-electrolyte solution CES. In total, subjects consumed each carbohydrate-electrolyte drink with the addition of mg, mg, and mg of caffeine.

In regard to performance, subjects achieved significantly faster times following ingestion of both the CES mg and CES mg dosages, as compared to placebo and CES without addition of caffeine [ 56 ]. Finally, Kovacs et al. It should also be mentioned the authors reported wide-ranging post-exercise urinary caffeine concentrations within subjects, which could possibly be explained by inter-individual variation in caffeine liver metabolism [ 56 ].

Grandjean et al. An interesting study published by Fiala and colleagues [ 90 ] investigated rehydration with the use of caffeinated and caffeine-free Coca-Cola ®. In a double-blind crossover manner, and in a field setting with moderate heat conditions, subjects participated in three, twice daily, 2-hr practices.

Athletes consumed water during exercise, and on separate occasions, either of the Coca-Cola © treatments post-exercise. As a result, no statistical differences were found for measures such as heart rate, rectal temperatures, change in plasma volume, or sweat rate [ 90 ].

It should be noted, however, the authors also reported a negative change in urine color for the mornings of Day 1 and 3, which was a possible indication of an altered hydration status; although, it was not evident at any other time point during the experiment.

Therefore, Fiala et al. Roti et al. The study included 59 young, active males. The EHT consisted of walking on a treadmill at 1. Millard-Stafford and colleagues [ 92 ] published results from a study that examined the effects of exercise in warm and humid conditions when consuming a caffeinated sports drink.

In conclusion, no significant differences in blood volume were present for any of the three treatments; therefore, caffeine did not adversely affect hydration and thus performance of long duration in highly trained endurance athletes [ 92 ].

In addition, heat dissipation was not negatively affected [ 93 ]. Therefore, while there may be an argument for caffeine-induced dieresis at rest, the literature does not indicate any significant negative effect of caffeine on sweat loss and thus fluid balance during exercise that would adversely affect performance.

Consequently, the International Olympic Committee mandates an allowable limit of 12 μg of caffeine per ml of urine [ 6 , 15 ]. Caffeine consumption and urinary concentration is dependent on factors such as gender and body weight [ 94 ].

Therefore, consuming cups of brewed coffee that contain approximately mg per cup would result in the maximum allowable urinary concentration [ 15 , 94 ]. In addition, the World Anti-Doping Agency does not deem caffeine to be a banned substance [ 96 ], but has instead included it as part of the monitoring program [ 97 ] which serves to establish patterns of misuse in athletic competition.

The scientific literature associated with caffeine supplementation is extensive. It is evident that caffeine is indeed ergogenic to sport performance but is specific to condition of the athlete as well as intensity, duration, and mode of exercise. Therefore, after reviewing the available literature, the following conclusions can be drawn:.

The majority of research has utilized a protocol where caffeine is ingested 60 min prior to performance to ensure optimal absorption; however, it has also been shown that caffeine can enhance performance when consumed min prior to exercise. During periods of sleep deprivation, caffeine can act to enhance alertness and vigilance, which has been shown to be an effective aid for special operations military personnel, as well as athletes during times of exhaustive exercise that requires sustained focus.

Caffeine is an effective ergogenic aid for sustained maximal endurance activity, and has also been shown to be very effective for enhancing time trial performance. Recently, it has been demonstrated that caffeine can enhance, not inhibit, glycogen resynthesis during the recovery phase of exercise.

Caffeine is beneficial for high-intensity exercise of prolonged duration including team sports such as soccer, field hockey, rowing, etc. The literature is inconsistent when applied to strength and power activities or sports. It is not clear whether the discrepancies in results are due to differences in training protocols, training or fitness level of the subjects, etc.

Nonetheless, more studies are needed to establish the effects of caffeine vis a vis strength-power sports. Research pertaining exclusively to women is limited; however, recent studies have shown a benefit for conditioned strength-power female athletes and a moderate increase in performance for recreationally active women.

The scientific literature does not support caffeine-induced dieresis during exercise. In fact, several studies have failed to show any change in sweat rate, total water loss, or negative change in fluid balance that would adversely affect performance, even under conditions of heat stress.

Harland B: Caffeine and nutrition. Article CAS PubMed Google Scholar. Fredholm BB: Adenosine, adenosine receptors and the actions of caffeine. Pharmacol Toxicol.

McArdle WD, Katch FI, Katch VL: Exercise physiology. Google Scholar. Carrillo JA, Benitez J: Clinically significant pharmacokinetic interaction between dietary caffeine and medications.

Clin Pharmacokinet. Fredholm BB, Battig K, Holmen J, Nehlig A, Zvartau EE: Actions of caffeine in the brain with special reference to factors that contribute to its widespread use. Pharmacol Rev. CAS PubMed Google Scholar.

Graham TE: Caffeine and exercise. Metabolism, endurance and performance Sports Med. Tang-Liu DD, Williams RL, Riegelman S: Disposition of caffeine and its metabolites in man.

The Journal of Pharmacology and Experimental Therapeutics. Graham TE, Spriet LL: Metabolic, catecholamine, and exercise performance responses to various doses of caffeine. J Appl Physiol. Powers SK, Howley ET: Exercise physiology: Theory and application to fitness and performance.

Robertson D, Frolich JC, Carr RK, Watson HT, Hollifield JW, Shand D, Oates HA: Effects of caffeine on plasma renin activity, catecholmines and blood pressure. N Engl J Med. McCall AL, Millington WR, Wurtman RJ: Blood-brain barrier transport of caffeine: Dose-related restriction of adenine transport.

Life Sci. The ergogenic effects of caffeine can vary depending on dosing, timing, exercise intensity, duration, and habitual or naïve caffeine use. Athletes should use caution if considering using caffeine if they have medical conditions or prone to sleep disturbances, and consult with their healthcare provider.

See our course catalog for free nutrition courses, CEU courses, and the nutrition certification program. She holds certifications from NASM and ACE in personal training, corrective exercise, sports performance, group exercise, fitness nutrition, and health coaching. Previous San Diego Fall Prevention Task Force Chair, she develops continuing education curriculum for many fitness organizations in addition to personal training, writing, and helping coach youth soccer.

Stacey Penney, MS, NASM-CPT, CES, PES, CNC, is the Content Strategist with NASM and AFAA. At NASM and AFAA she drives the content for American Fitness Magazine, blog and the social media platforms. org Fitness CPT Nutrition CES Sports Performance Workout Plans Wellness. Nutrition Caffeine and Exercise: Benefits for Performance.

Caffeine is everywhere, essentially. Read on! The Health Consequences of Caffeine Part of the appeal of caffeine is that it has minimal health consequences for generally healthy individuals when taken in low-to-moderate amounts.

I t was eventually removed from the list as violation threshold levels were well beyond doses giving athletes a competitive edge 2. How Caffeine is absorbed in the body Caffeine is absorbed in the gastrointestinal tract and quickly metabolized by the liver. Health Benefits and Cautions of Caffeine Just about every week a new piece of research on caffeine and its health benefits makes the headlines.

Benefits of Caffeine on Athletic Performance Need to improve ball-passing accuracy in a field sport? Some common caffeine sources include 9 : Cola 12 oz.

What do Athletes Know? Caffeine Wrap-Up Though we are not promoting the use of caffeine, this article shares some of the benefits and dosing strategies for improving performance.

Check out our Nutrition Courses! References: Goldstein, E. Antonio, J. International society of sports nutrition position stand: caffeine and performance. Journal of the International Society of Sports Nutrition , 7 Prevalence of caffeine use in elite athletes following its removal from the World Anti-Doping Agency list of banned substances.

NASM Essentials of Sports Performance. Evert, A. S National Library of Medicine. National Library of Medicine, 5 May Butt, M. Critical Reviews in Food Science and Nutrition 51 4 Welsh E. Cochrane Database of Systematic Reviews Issue 1.