IBS management strategies Oxide, 6155 — Physicsl As such, focus Physical performance enhancement Pharmaceutical-grade raw materials to Physical performance enhancement action of caffeine Enhancemnt exercise within the central and peripheral nervous systems, which could alter the rate of perceived exertion Physical performance enhancement [enhahcement,], muscle pain [ enhancrment, ], and possibly the ability of skeletal muscle to generate force [ ]. Caffeine and its effects on health have been a longstanding topic of interest, and caffeine continues to be a dietary compound of concern in public health, as indicated by extensive investigations [ 78910 ]. Warren GL, Park ND, Maresca RD, McKibans KI, Millard-Stafford ML. Allen DG, Lamb GD, Westerblad H. This results in positive effects on mood, vigilance, focus, and alertness in most, but not all, individuals [].

Physical performance enhancement -

ISSN X. World Anti-Doping Agency. In recent decennia however, it became clear that the central nervous system plays an important role in the onset of fatigue during prolonged exercise Klass et al. This indicates that subjects did not feel they were producing more power and consequently more heat.

The authors concluded that the "safety switch" or the mechanisms existing in the body to prevent harmful effects are overridden by the drug administration Roelands et al.

Taken together, these data indicate strong ergogenic effects of an increased DA concentration in the brain, without any change in the perception of effort. The combined effects of DA and NA on performance in the heat were studied by our research group on a number of occasions.

Coinciding with this ergogenic effect, the authors observed core temperatures that were much higher compared with the placebo situation. Interestingly, this occurred without any change in the subjective feelings of thermal sensation or perceived exertion.

Similar to the methylphenidate study Roelands et al. Sports Health. February Molecular and Cellular Biochemistry. December International Journal of Sports Physiology and Performance. British Journal of Sports Medicine. Molecular Pathology. October April Endocrine Reviews. Current Drug Targets.

European Medicines Agency Committee on Herbal Medicinal Products. Journal of Cognitive Neuroscience. The present meta-analysis was conducted to estimate the magnitude of the effects of methylphenidate and amphetamine on cognitive functions central to academic and occupational functioning, including inhibitory control, working memory, short-term episodic memory, and delayed episodic memory.

In addition, we examined the evidence for publication bias. Forty-eight studies total of 1, participants were included in the analyses. We found evidence for small but significant stimulant enhancement effects on inhibitory control and short-term episodic memory. Small effects on working memory reached significance, based on one of our two analytical approaches.

Effects on delayed episodic memory were medium in size. However, because the effects on long-term and working memory were qualified by evidence for publication bias, we conclude that the effect of amphetamine and methylphenidate on the examined facets of healthy cognition is probably modest overall.

In some situations, a small advantage may be valuable, although it is also possible that healthy users resort to stimulants to enhance their energy and motivation more than their cognition. Earlier research has failed to distinguish whether stimulants' effects are small or whether they are nonexistent Ilieva et al.

The present findings supported generally small effects of amphetamine and methylphenidate on executive function and memory. Specifically, in a set of experiments limited to high-quality designs, we found significant enhancement of several cognitive abilities. The results of this meta-analysis cannot address the important issues of individual differences in stimulant effects or the role of motivational enhancement in helping perform academic or occupational tasks.

However, they do confirm the reality of cognitive enhancing effects for normal healthy adults in general, while also indicating that these effects are modest in size.

Retrieved 13 October Molecular and Cellular Endocrinology. Drug Testing and Analysis. Indian Journal of Orthopaedics. The Journal of Steroid Biochemistry and Molecular Biology.

Canadian Journal of Applied Physiology. August Medicine and Science in Sports and Exercise. Veterinary and Human Toxicology. Medicina Nei Secoli. Journal of the International Society of Sports Nutrition. World Psychiatry. The Journal of Clinical Endocrinology and Metabolism. An overview".

The Journal of Urology. National Institute on Drug Abuse. Retrieved 5 April July Internal Medicine. And it is not legal. It's never safe to buy anabolic steroids from a drug dealer. The drugs could be tainted or labeled the wrong way. Androstenedione, also called andro, is a hormone everyone's body makes.

The body turns andro into the hormone testosterone and a form of the hormone estrogen. Andro can be made in a lab.

Some drugmakers and workout magazines claim that andro products help athletes train harder and recover faster. But some studies show that andro doesn't boost testosterone. They also show that muscles don't get stronger. Andro is legal to use only if a health care provider prescribes it.

It's not legal to use as a doping drug in the United States. Andro can damage the heart and blood vessels in anyone who takes it. This raises the risk of a serious problem that can happen when the heart doesn't get enough blood, called a heart attack. It also raises the risk of a condition that keeps the brain from getting enough oxygen, called a stroke.

Heart attack and stroke can be deadly. Athletes take human growth hormone, also called somatotropin, to build more muscle and do better at their sports.

But studies don't clearly prove that human growth hormone boosts strength or helps people exercise longer. A health care provider can prescribe human growth hormone for some health reasons.

It is given as a shot. Erythropoietin is a type of hormone. It treats anemia in people with severe kidney disease. It raises the level of red blood cells. It also raises the levels of the protein in red blood cells that carries oxygen to the body's organs, called hemoglobin.

Taking erythropoietin improves how oxygen moves to the muscles. It's common for athletes who exercise for long amounts of time to use a lab-made type of erythropoietin called epoetin. In the s, it was common for pro cyclists to use erythropoietin.

But the drug may have played a role in at least 18 deaths. Doping with erythropoietin may raise the risk of serious health problems.

These include stroke, heart attack and blocked arteries in the lung. Diuretics are drugs that change the body's balance of fluids and salts. They can cause the body to lose water, which can lower an athlete's weight.

Diuretics also may help athletes pass drug tests that check for signs of drugs in the urine. They dilute the urine and may hide traces of drugs. Diuretics can cause side effects when you take them at any dose — even at doses that health care providers suggest.

These drugs make athletes more likely to have side effects such as:. Nutrients are vitamins and minerals in foods that are good for you.

Some people try to get more nutrients from products called supplements. Supplements are sold in stores and online as powders or pills. One supplement that's popular with athletes is called creatine monohydrate.

The body makes its own creatine too. It helps muscles release energy. Creatine supplements may help athletes gain small, short-term bursts of power. Creatine seems to help muscles make more of an energy source called adenosine triphosphate ATP. ATP stores and moves energy in the body's cells.

It's used for activity that involves quick bursts of movement, such as weightlifting or sprinting. But there's no proof that creatine helps you do better at sports that make you breathe at a higher rate and raise your heart rate, called aerobic sports.

Some athletes try to gain weight so they can get bigger in size. Creatine may help you put on weight over time. But that might be due to the extra water that creatine causes the body to hold on to. Water is drawn into muscle tissue, away from other parts of the body.

That puts you at risk of getting dehydrated. Studies show that it's safe for healthy adults to use creatine for a short or long time. It's important to use the doses that creatine makers suggest on the package. Stimulants boost the levels of some chemicals in the brain. They also make the heart beat faster and raise blood pressure.

Common stimulants include caffeine and drugs called amphetamines. Cold medicines often have a stimulant in them. Energy drinks are popular among many athletes. They often have high doses of caffeine and other stimulants.

The street drugs cocaine and methamphetamine also are stimulants. Some athletes may seem to get an edge from performance-enhancing drugs.

Prolonged abuse of anabolic steroids very often results in physical addiction. Abusers must undergo a strict, medically-supervised withdrawal program. Sometimes, athletes who use anabolic steroids may share the needles, syringes or other equipment they use to inject these drugs.

By sharing needles, syringes or other equipment, a person becomes a high risk for HIV transmission. HIV is the virus that causes AIDS. If a person shares needles, syringes and other equipment to inject steroids into the vein IV , in the muscles or under the skin, small amounts of blood from the person infected with HIV may be injected into the bloodstream of the next person to use the equipment.

HIV attacks the body's defense system, making the body less able to fight off infections and cancers. There's no vaccine or cure for HIV or AIDS. People who may have been exposed to HIV should be tested. If they find out they have the virus, they can start treatment early. You can't tell just be looking at someone if he or she has HIV.

And, since someone can be infected with HIV for many years without having any symptoms, some people may not know they have HIV. Anyone who has ever shared a needle to shoot any drugs -- even once -- could become infected with HIV and should be tested.

There are many ways to increase your strength and improve your appearance. If you are serious about your sport and health, keep the following tips in mind:. The abuse of anabolic steroids by high school, college and other amateur athletes is a dangerous practice.

Participants in amateur sports must be made aware of the physical and emotional dangers associated with steroid abuse. The "win at any cost " attitude embraced by some athletes must be redirected and replaced by personal dedication to the sport; a thorough knowledge of the sport's physical demands and requirements; maintenance of a healthy lifestyle; and, an appreciation of the satisfaction that comes from participation.

skip to main content Your browser does not support iFrames. Navigation menu. Anabolic Steroids and Sports: Winning at any Cost "Anabolic Steroids and Sports: Winning at any Cost" is also available in Portable Document format PDF, KB, 8pg.

Versión en español PDF, KB, 8pg. Why Some Athletes Abuse Anabolic Steroids Believing that anabolic steroids can improve competitiveness and performance, uninformed or misguided athletes, sometimes encouraged by coaches or parents, abuse these drugs to build lean muscle mass, promote aggressiveness, and increase body weight.

Supplements Over the counter dietary supplements, such as creatine, should be used with caution. The Dangers of Anabolic Steroid Abuse When improperly used, anabolic steroids can cause serious health problems such as high blood pressure and heart disease; liver damage and cancers; and, stroke and blood clots.

These effects can cause any or all of the following problems in men: Temporary infertility or sterility reversible Altered sex drive Prostate enlargement, and increased prostate cancer risk Irreversible breast enlargement Painful erections Shrinkage of the testicles Reduced levels of testosterone Abnormal sperm production Increased levels of estrogen Health care providers have reported the following problems in women: Increased risk of cervical and endometrial cancer Increased risk of osteoporosis Temporary infertility or sterility reversible Altered sex drive Birth defects in future children Changes in fat distribution Growth of facial and body hair Deepening of the voice Shrinkage of the breasts and uterus Clitoral enlargement Menstrual irregularity Changes in the male reproductive system are often reversible, if anabolic steroids have not been abused for a long period of time.

If you are serious about your sport and health, keep the following tips in mind: Train safely, without using drugs. Eat a healthy diet.

People use performance enhancers to improve their enhacnement Physical performance enhancement high-intensity physical exercise. A performance enhancer, Herbal digestive aid ergogenic perfornance, is ehnancement that gives you Physical performance enhancement mental or Physical performance enhancement edge while exercising or competing. This can range from caffeine and sports drinks to illegal substances. There are a variety of both safe and harmful ergogenic aids. Many of these supplements are marketed to boost athletic performance. However, scientific proof of their effectiveness is sometimes lacking or contradictory. There are other ergogenic aids that are generally recognized as safe by the Food and Drug Administration. Simply put, PEDs have the ability perfprmance potential to Physicak alter the eprformance body and biological functions, including the ability to Nutrient-dense foods improve athletic pegformance Physical performance enhancement performmance instances. These drugs, Physical performance enhancement, can Petformance extremely Allergy relief for seasonal allergies and, in certain situations, deadly. This section provides answers to common questions about the health and safety risks associated with substances and methods on the WADA Prohibited List the List. It also provides information concerning the legitimate medical use of substances. When these compounds are misused, it constitutes a breach of ethics both by the user and supplier. The primary medical use of these compounds is to treat delayed puberty, some types of impotence, and wasting of the body caused by HIV infection or other muscle-wasting diseases.

Physical performance enhancement -

In contrast, previous studies either did not observe any impact of the CYP1A2 gene in caffeine-exercise studies [ , ], or reported benefits only in slow metabolizers [ 75 ]. There are several reasons that may explain discrepancies in study outcomes.

The effects of genotype on performance might be the most prominent during training or competition of longer duration or an accumulation of fatigue aerobic or muscular endurance [ ], where caffeine appears to provide its greatest benefits, and where the adverse effects to slow metabolizers are more likely to manifest [ , ].

Indeed, in a study of performance in elite basketball players [ ], only in those with the AA genotype caffeine improved repeated jumps which requires maintaining velocity at take-off repeatedly as an athlete fatigues throughout a game muscular endurance - even though there was no caffeine-genotype interaction effect for this outcome.

However, caffeine similarly improved performance in those with the both AA and C-genotypes during a simulated basketball game [ ]. In a cross-over design of 30 resistance-trained men, caffeine ingestion resulted in a higher number of repetitions in repeated sets of three different exercises, and for total repetitions in all resistance exercises combined, which resulted in a greater volume of work compared to placebo conditions, but only in those with the CYP1A2 AA genotype [ ].

Although more research is warranted, there is a growing body of evidence to support the role of CYP1A2 in modifying the effects of caffeine ingestion on aerobic or muscular endurance-type exercise, which helps to determine which athletes are most likely to benefit from caffeine.

The ADORA2A gene is another genetic modifier of the effects of caffeine on performance. The adenosine A 2A receptor, encoded by the ADORA2A gene, has been shown to regulate myocardial oxygen demand and increase coronary circulation by vasodilation [ , ].

The A 2A receptor is also expressed in the brain, where it has significant roles in the regulation of glutamate and dopamine release, with associated effects on insomnia and pain [ , ]. The antagonism of adenosine receptors after caffeine ingestion is modified by the ADORA2A gene, which may allow greater improvements in dopamine transmission and lead to norepinephrine and epinephrine release due to increased neuronal firing [ ] in some genotypes versus others.

Dopamine has been associated with motivation and effort in exercising individuals, and this may be the mechanism by which differences in response to caffeine are manifested [ , , ].

Currently, only one small pilot study has examined the effect of the ADORA2A gene rs on the ergogenic effects of caffeine under exercise conditions [ ].

Twelve female subjects underwent a double-blinded, crossover trial comprising two min cycling time trials following caffeine ingestion or placebo.

Caffeine benefitted all six subjects with the TT genotype, but only one of the six C allele carriers. Further studies are needed to confirm these preliminary findings and should include a large enough sample to distinguish any effects between the different C allele carriers i.

CT vs. CC genotypes and potential effects related to sex. The ADORA2A rs genotype has also been implicated, by both objective and subjective measures, in various parameters of sleep quality after caffeine ingestion in several studies [ , , , ].

Adenosine promotes sleep by binding to its receptors in the brain, mainly A 1 and A 2A receptors, and caffeine exerts an antagonist effect, blocking the receptor and reversing the effects of adenosine and promoting wakefulness [ ]. This action of caffeine may also serve athletes well under conditions of jetlag, and irregular or early training or competition schedules.

Psychomotor speed relies on the ability to respond, rapidly and reliably, to randomly occurring stimuli which is a critical component of, and characteristic of, most sports [ ]. Genetic variation in ADORA2A has been shown to be a relevant determinant of psychomotor vigilance in the rested and sleep-deprived state and modulates individual responses to caffeine after sleep deprivation [ ].

Those with the CC genotype of ADORA2A rs consistently performed on a higher level on the sustained vigilant attention task than T-allele -carriers; however, this was tested in ADORA2A haplotypes that included combinations of 8 SNPs.

This work provides the basis for future genetic studies of sleep using individual ADORA2A SNPs. As mentioned, the ADORA2A genotype has also been implicated in sleep quality and increases in sleep disturbance [ ].

Increased beta activity in nonREM sleep may characterize individuals with insomnia when compared with healthy good sleepers [ ]. A functional relationship between the ADORA2A genotype and the effect of caffeine on EEG beta activity in nonREM sleep has previously been reported [ ], where the highest rise was in individuals with the CC genotype, approximately half in the CT genotype, whereas no change was present in the TT genotype.

Consistent with this observation, the same study found individuals with the CC and TC genotypes appeared to confer greater sensitivity towards caffeine-induced sleep disturbance compared to the TT genotype [ ].

This suggests that a common variant in ADORA2A contributes to subjective and objective responses to caffeine on sleep. Given that anxiety may be normalized in elite sports even at clinical levels, factors that contribute to anxiety should be mitigated whenever possible.

Anxiety may be caused by stress-related disorders burnout , poor quality sleep patterns often related to caffeine intakes and possibly as a response to caffeine ingestion due to genetic variation, even at low levels [ ]. As previously mentioned, caffeine blocks adenosine receptors, resulting in the stimulating effects of caffeine [ ].

A common variation in the ADORA2A adenosine A 2A receptor gene contributes to the differences in subjective feelings of anxiety after caffeine ingestion [ , ], especially in those who are habitually low caffeine consumers [ ]. This may be particularly relevant to athletes who possess the TT variant of rs in the ADORA2A gene.

These individuals are likely to be more sensitive to the stimulating effects of caffeine and experience greater increases in feelings of anxiety after caffeine intake than do individuals with either the CT or CC variant [ , , ].

Sport psychologists commonly work with athletes to help them overcome anxiety about performance during competitions. Anxiety before or during athletic competitions can interfere not only in performance, but also in increased injury risk [ ]. Athletes who are more prone to performance anxiety may exacerbate their risk for feelings of anxiety depending on their caffeine use and which variant of the ADORA2A gene they possess.

Monitoring the actions of caffeine in those individuals who are susceptible, may alleviate some of the related feelings of anxiety with caffeine use. Given that anxiety may disrupt concentration and sleep and negatively impact social interactions, athletes with higher risks and prevalence for anxiety, may want to limit or avoid caffeine consumption if caffeine is a known trigger during times where they are feeling anxious or stressed, such as at sporting competitions or social gatherings or other work and school events.

The importance of both sleep and caffeine as an ergogenic aid to athletes highlights the importance of optimizing rest and recovery through a better understanding of which athletes may be at greater risk of adverse effects of caffeine on mood and sleep quality, possibly due to genetic variation.

This information will allow athletes and coaching staff to make informed decisions on when and if to use caffeine when proximity to sleep is a factor. These considerations will also be in conjunction with the possibility that an athlete will benefit from caffeine in endurance-based exercise as determined in part, by their CYP1A2 genotype, albeit with a clear need for future research.

The quantification of habitual caffeine intake is difficult, which is problematic for studies aiming to compare performance outcomes following caffeine ingestion in habitual versus non-habitual caffeine users. This concern is highlighted by reports showing large variability in the caffeine content of commonly consumed beverages, e.

Self-reported intakes may therefore be unreliable. Newly discovered biomarkers of coffee consumption may be more useful for quantifying intakes in the future, but currently, these are not widely available [ ].

Different protocols for the length of the caffeine abstinence period preceding data collection is also a relevant factor in determining variability in performance outcomes.

For example, in shorter caffeine abstinence periods e. alleviating the negative symptoms of withdrawal, which in itself may improve performance [ ].

These effects may be more pronounced in those genetically predisposed to severe withdrawal effects [ ]. Although genes have been associated with habitual caffeine intake using GWAS research [ , ], it is important to highlight that these associations are not directly applicable to determining differences in performance outcomes in response to acute caffeine doses for regular or habitual caffeine users versus non-habitual users.

Furthermore, associations between genes and habitual caffeine intake do not elucidate potential mechanisms by which caffeine intake behaviors may influence subsequent performance following caffeine supplementation [ , ].

In animal model studies, regular consumption of caffeine has been associated with an upregulation of the number of adenosine receptors in the vascular and neural tissues of the brain [ ]. Although, this did not appear to modify the effects of caffeine in one study [ ], in another, chronic caffeine ingestion by mice caused a marked reduction in locomotor exploratory activity [ ].

Changes in adenosine receptor number or activity have not been studied in humans. There does not appear to be a consistent difference in the performance effects of acute caffeine ingestion between habitual and non-habitual caffeine users, and study findings remain equivocal. In one study, habitual stimulation from caffeine resulted in a general dampening of the epinephrine response to both caffeine and exercise; however, there was no evidence that this impacted exercise performance [ ].

Four weeks of caffeine ingestion resulted in increased tolerance to acute caffeine supplementation in previously low habitual caffeine consumers, with the ergogenic effect of acute caffeine supplementation no longer apparent [ ]. Caffeine ingestion improved performance as compared to placebo and control, with no influence of habitual caffeine intake.

However, a limitation of this study is the short h caffeine withdrawal period in all groups which may have resulted in performance improvements due to the reversal of caffeine withdrawal effects, rather than impact of acute-on-chronic caffeine administration and the effects of habituation to caffeine on exercise performance [ , ].

In addition, habitual caffeine intake was estimated using a food frequency questionnaire, which might be a limitation given the already mentioned variation of caffeine in coffee and different supplements.

There is wide variability in caffeine content of commonly consumed items, and as such, an objective measure e.

Based on these observations, the assumption that habitual and nonhabitual caffeine consumers will or will not respond differently to caffeine supplementation during exercise, requires further study.

However, caffeine appears to be most beneficial during times or in sports where there is an accumulation of fatigue, i. A recent review [ ] reported that the effect size of caffeine benefits increase with the increasing duration of the time trial event, meaning that timing caffeine intake closer to a time of greater fatigue, i.

This supports the notion that endurance athletes with longer races may benefit most from caffeine for performance enhancement since they have the greatest likelihood of being fatigued. This also supports findings in other investigations that show ingesting caffeine at various time points including late in exercise may be most beneficial [ ].

For example, an early study [ ] aimed to understand whether or not there were benefits to a common practice among endurance athletes, such as those participating in marathons and triathlons, which is to drink flat cola toward the end of an event. When researchers investigated the ingestion of a low dose of caffeine toward the end of a race e.

The study also demonstrated that the effect was due to the caffeine and not the carbohydrate, which may also aid performance as fuel stores become depleted [ ]. This may have been due to the faster absorption with caffeinated gum consumption, and due to the continued increase in plasma caffeine concentrations during the cycling time trial, when athletes may become fatigued i.

However, there was significant interindividual variability, highlighting the need for athletes to experiment with their own strategies as far as dosing and timing are concerned. The optimal timing of caffeine ingestion may depend on the source of caffeine. As stated earlier, some of the alternate sources of caffeine such as caffeine chewing gums may absorb more quickly than caffeine ingested in caffeine-containing capsules [ 60 ].

Therefore, individuals interested in supplementing with caffeine should consider that timing of caffeine ingestion will likely be influenced by the source of caffeine. Currently, only a few investigations [ 96 , , , , , ] have included both trained and untrained subjects in their study design.

A limitation of this study is that the swimming exercise task differed between the trained and untrained participants. Specifically, the study utilized m swimming for the trained swimmers and m for the untrained swimmers, which is a likely explanation for these findings.

However, some have also postulated that this is because athletes perform more reliably on a given task than nonathletes, and increased test-retest reliability might prevent type II errors [ ].

In contrast to the above evidence regarding the importance of training status, other research has shown that training status does not moderate the ergogenic effects of caffeine on exercise performance. One study [ ] showed similar performance improvements 1.

Similarly, Astorino et al. More recently, a small study by Boyett et al. Subjects completed four experimental trials consisting of a 3-km cycling time trial performed in randomized order for each combination of time of day morning and evening and treatment.

They reported that both untrained and trained subjects improved performance with caffeine supplementation in the morning; however, only the untrained subjects improved when tested in the evening.

Although there were some limitations to this study, these observations indicate that trained athletes are more likely to experience ergogenic effects from caffeine in the morning, while untrained individuals appear to receive larger gains from caffeine in the evening than their trained counterparts.

This may further complicate the training status data with a possible temporal effect [ ]. The concentration of adenosine receptors the primary target of caffeine do appear to be higher in trained compared to untrained individuals, but this has only been reported in animal studies [ ].

Boyett et al. Although some studies comparing training status of subjects support the notion [ ] that training influences response to caffeine during exercise, most do not [ 96 , , ] and this was also the finding in a subsequent meta-analysis [ ].

It is possible that the only difference between trained and untrained individuals is that trained individuals likely have the mental discipline to exercise long or hard enough to benefit more from the caffeine stimulus, which might provide an explanation for why in some studies, trained individuals respond better to caffeine [ ].

Currently, it seems that trained and untrained individuals experience similar improvements in performance following caffeine ingestion; however, more research in this area is warranted.

The impacts of caffeine on sleep and behavior after sleep deprivation are widely reported [ ]. Sleep is recognized as an essential component of physiological and psychological recovery from, and preparation for, high-intensity training in athletes [ , ].

Chronic mild to moderate sleep deprivation in athletes, potentially attributed to caffeine intakes, may result in negative or altered impacts on glucose metabolism, neuroendocrine function, appetite, food intake and protein synthesis, as well as attention, learning and memory [ ].

Objective sleep measures using actigraphy or carried out in laboratory conditions with EEG have shown that caffeine negatively impacts several aspects of sleep quality such as: sleep latency time to fall asleep , WASO wake time after sleep onset , sleep efficiency and duration [ ].

Studies in athletes have also shown adverse effects in sleep quality and markers for exercise recovery after a variety of doses of caffeine ingestion [ , , ]. Although caffeine is associated with sleep disturbances, caffeine has also been shown to improve vigilance and reaction time and improved physical performance after sleep deprivation [ , , , , ].

This may be beneficial for athletes or those in the military who are traveling or involved in multiday operations, or sporting events and must perform at the highest level under sleep-deprived conditions [ , , , ]. Even though caffeine ingestion may hinder sleep quality, the time of day at which caffeine is ingested will likely determine the incidence of these negative effects.

For example, in one study that included a sample size of 13 participants, ingestion of caffeine in the morning hours negatively affected sleep only in one participant [ ]. Unfortunately, athletes and those in the military are unlikely to be able to make adjustments to the timing of training, competition and military exercises or the ability to be combat ready.

However, to help avoid negative effects on sleep, athletes may consider using caffeine earlier in the day whenever possible. Pronounced individual differences have also been reported where functional genetic polymorphisms have been implicated in contributing to individual sensitivity to sleep disruption [ , ] and caffeine impacts after sleep deprivation [ ] as discussed in the Interindividual variation in response to caffeine: Genetics section of this paper.

As with any supplement, caffeine ingestion is also associated with certain side-effects. Some of the most commonly reported side-effects in the literature are tachycardia and heart palpitations, anxiety [ , ], headaches, as well as insomnia and hindered sleep quality [ , ].

For example, in one study, caffeine ingestion before an evening Super Rugby game resulted in a delay in time at sleep onset and a reduction in sleep duration on the night of the game [ ]. Caffeine ingestion is also associated with increased anxiety; therefore, its ingestion before competitions in athletes may exacerbate feelings of anxiety and negatively impact overall performance see caffeine and anxiety section.

For example, athletes competing in sports that heavily rely on the skill component e. However, athletes in sports that depend more on physical capabilities, such as strength and endurance e.

These aspects are less explored in research but certainly warrant consideration in the practical context to optimize the response to caffeine supplementation. The primary determinant in the incidence and severity of side-effects associated with caffeine ingestion is the dose used.

Side-effects with caffeine seem to increase linearly with the dose ingested [ ]. Therefore, they can be minimized—but likely not fully eliminated—by using smaller doses, as such doses are also found to be ergogenic and produce substantially fewer side-effects [ ]. In summary, an individual case-by-case basis approach is warranted when it comes to caffeine supplementation, as its potential to enhance performance benefit needs to be balanced with the side-effects risk.

In addition to exercise performance, caffeine has also been studied for its contribution to athletes of all types including Special Forces operators in the military who are routinely required to undergo periods of sustained cognitive function and vigilance due to their job requirements Table 1.

Hogervorst et al. They found that caffeine in a carbohydrate-containing performance bar significantly improved both endurance performance and complex cognitive ability during and after exercise [ 82 ].

Antonio et al. This matches a IOM report [ ] that the effects of caffeine supplementation include increased attention and vigilance, complex reaction time, and problem-solving and reasoning.

One confounding factor on cognitive effects of caffeine is the role of sleep. Special Forces military athletes conduct operations where sleep deprivation is common. A series of different experiments [ 42 , , , , , , , ] have examined the effects of caffeine in real-life military conditions.

In three of the studies [ , , ], soldiers performed a series of tasks such as a 4 or 6. The investigators found that vigilance was either maintained or enhanced under the caffeine conditions vs. placebo , in addition to improvements in run times and obstacle course completion [ , , ].

Similarly, Lieberman et al. Navy Seals. The positive effects of caffeine on cognitive function were further supported by work from Kamimori et al.

The caffeine intervention maintained psychomotor speed, improved event detection, increased the number of correct responses to stimuli, and increased response speed during logical reasoning tests.

Under similar conditions of sleep deprivation, Tikuisis et al. When subjects are not sleep deprived, the effects of caffeine on cognition appear to be less effective.

For example, Share et al. In addition to the ability of caffeine to counteract the stress from sleep deprivation, it may also play a role in combatting other stressors.

Gillingham et al. However, these benefits were not observed during more complex operations [ ]. Crowe et al. Again, no cognitive benefit was observed. Other studies [ , , , ] support the effects of caffeine on the cognitive aspects of sport performance, even though with some mixed results [ , ].

Foskett et al. This was supported by Stuart et al. firefighting, military related tasks, wheelchair basketball [ ]. The exact mechanism of how caffeine enhances cognition in relation to exercise is not fully elucidated and appears to work through both peripheral and central neural effects [ ].

In a study by Lieberman et al. Repeated acquisition are behavioral tests in which subjects are required to learn new response sequences within each experimental session [ ]. The researchers [ 42 ] speculated that caffeine exerted its effects from an increased ability to sustain concentration, as opposed to an actual effect on working memory.

Other data [ ] were in agreement that caffeine reduced reaction times via an effect on perceptual-attentional processes not motor processes. This is in direct contrast to earlier work that cited primarily a motor effect [ ]. Another study with a sugar free energy drink showed similar improvements in reaction time in the caffeinated arm; however, they attributed it to parallel changes in cortical excitability at rest, prior, and after a non-fatiguing muscle contraction [ ].

The exact cognitive mechanism s of caffeine have yet to be elucidated. Based on some of the research cited above, it appears that caffeine is an effective ergogenic aid for individuals either involved in special force military units or who may routinely undergo stress including, but not limited to, extended periods of sleep deprivation.

Caffeine in these conditions has been shown to enhance cognitive parameters of concentration and alertness. It has been shown that caffeine may also benefit sport performance via enhanced passing accuracy and agility.

However, not all of the research is in agreement. It is unlikely that caffeine would be more effective than actually sleeping, i. Physical activity and exercise in extreme environments are of great interest as major sporting events e. Tour de France, Leadville , Badwater Ultramarathon are commonly held in extreme environmental conditions.

Events that take place in the heat or at high altitudes bring additional physiological challenges i. Nonetheless, caffeine is widely used by athletes as an ergogenic aid when exercising or performing in extreme environmental situations.

Ely et al. Although caffeine may induce mild fluid loss, the majority of research has confirmed that caffeine consumption does not significantly impair hydration status, exacerbate dehydration, or jeopardize thermoregulation i. Several trials have observed no benefit of acute caffeine ingestion on cycling and running performance in the heat Table 2 [ , , ].

It is well established that caffeine improves performance and perceived exertion during exercise at sea level [ , , , ]. Despite positive outcomes at sea level, minimal data exist on the ergogenic effects or side effects of caffeine in conditions of hypoxia, likely due to accessibility of this environment or the prohibitive costs of artificial methods.

To date, only four investigations Table 3 have examined the effects of caffeine on exercise performance under hypoxic conditions [ , , , ]. Overall, results to date appear to support the beneficial effects of caffeine supplementation that may partly reduce the negative effects of hypoxia on the perception of effort and endurance performance [ , , , ].

Sources other than commonly consumed coffee and caffeine tablets have garnered interest, including caffeinated chewing gum, mouth rinses, aerosols, inspired powders, energy bars, energy gels and chews, among others. While the pharmacokinetics [ 18 , , , , ] and effects of caffeine on performance when consumed in a traditional manner, such as coffee [ 47 , 49 , 55 , , , , ] or as a caffeine capsule with fluid [ 55 , , , ] are well understood, curiosity in alternate forms of delivery as outlined in pharmacokinetics section have emerged due to interest in the speed of delivery [ 81 ].

A recent review by Wickham and Spriet [ 5 ] provides an overview of the literature pertaining to caffeine use in exercise, in alternate forms. Therefore, here we only briefly summarize the current research. Several investigations have suggested that delivering caffeine in chewing gum form may speed the rate of caffeine delivery to the blood via absorption through the extremely vascular buccal cavity [ 58 , ].

Kamimori and colleagues [ 58 ] compared the rate of absorption and relative caffeine bioavailability from caffeinated chewing gum and caffeine in capsule form. The results suggest that the rate of drug absorption from the gum formulation was significantly faster.

These findings suggest that there may be an earlier onset of pharmacological effects from caffeine delivered through the gum formulation. Further, while no data exist to date, it has been suggested that increasing absorption via the buccal cavity may be preferential over oral delivery if consumed closer to or during exercise, as splanchnic blood flow is often reduced [ ], potentially slowing the rate of caffeine absorption.

To date, five studies [ 59 , 60 , 61 , 62 , 63 ] have examined the potential ergogenic impact of caffeinated chewing gum on aerobic performance, commonly administered in multiple sticks Table 4.

To note, all studies have been conducted using cycling interventions, with the majority conducted in well-trained cyclists. However, more research is needed, especially in physically active and recreationally training individuals.

Four studies [ 64 , 66 , 68 , ] have examined the effect of caffeinated chewing gum on more anaerobic type activities Table 4. Specifically, Paton et al. The reduced fatigue in the caffeine trials equated to a 5. Caffeinated gum consumption also positively influenced performance in two out of three soccer-specific Yo-Yo Intermittent Recovery Test and CMJ tests used in the assessment of performance in soccer players [ 66 ].

These results suggest that caffeine chewing gums may provide ergogenic effects across a wide range of exercise tasks.

To date, only Bellar et al. Future studies may consider comparing the effects of caffeine in chewing gums to caffeine ingested in capsules. Specifically, the mouth contains bitter taste sensory receptors that are sensitive to caffeine [ ]. It has been proposed that activation of these bitter taste receptors may activate neural pathways associated with information processing and reward within the brain [ , , ].

Physiologically, caffeinated mouth rinsing may also reduce gastrointestinal distress potential that may be caused when ingesting caffeine sources [ , ]. Few investigations on aerobic [ 69 , 74 , 75 , 76 , ] and anaerobic [ 72 , 73 , 78 ] changes in performance, as well as cognitive function [ 70 , 71 ] and performance [ 77 ], following CMR have been conducted to date Table 5.

One study [ ] demonstrated ergogenic benefits of CMR on aerobic performance, reporting significant increases in distance covered during a min arm crank time trial performance. With regard to anaerobic trials, other researchers [ 72 ] have also observed improved performance, where recreationally active males significantly improved their mean power output during repeated 6-s sprints after rinsing with a 1.

While CMR has demonstrated positive outcomes for cyclists, another study [ 78 ] in recreationally resistance-trained males did not report any significant differences in the total weight lifted by following a 1. CMR appears to be ergogenic in cycling to include both longer, lower-intensity and shorter high-intensity protocols.

The findings on the topic are equivocal likely because caffeine provided in this source does not increase caffeine plasma concentration and increases in plasma concentration are likely needed to experience an ergogenic effect of caffeine [ 69 ].

Details of these studies, as well as additional studies may be found in Table 5. The use of caffeinated nasal sprays and inspired powders are also of interest. Three mechanisms of action have been hypothesized for caffeinated nasal sprays. Firstly, the nasal mucosa is permeable, making the nasal cavity a potential route for local and systemic substance delivery; particularly for caffeine, a small molecular compound [ 11 , 12 , 30 , 31 ].

Secondly, and similar to CMR, bitter taste receptors are located in the nasal cavity. The use of a nasal spray may allow for the upregulation of brain activity associated with reward and information processing [ ].

Thirdly, but often questioned due to its unknown time-course of action, caffeine could potentially be transported directly from the nasal cavity to the CNS, specifically the cerebrospinal fluid and brain by intracellular axonal transport through two specific neural pathways, the olfactory and trigeminal [ , ].

No significant improvements were reported in either anaerobic and aerobic performance outcome measures despite the increased activity of cingulate, insular, and sensory-motor cortices [ 79 ].

Laizure et al. Both were found to have similar bioavailability and comparable plasma concentrations with no differences in heart rate or blood pressure Table 6. While caffeinated gels are frequently consumed by runners, cyclists and triathletes, plasma caffeine concentration studies have yet to be conducted and only three experimental trials have been reported.

Cooper et al. In the study by Cooper et al. In contrast, Scott et al. utilized a shorter time period from consumption to the start of the exercise i. However, these ideas are based on results from independent studies and therefore, future studies may consider exploring the optimal timing of caffeine gel ingestion in the same group of participants.

More details on these studies may be found in Table 7. Similar to caffeinated gels, no studies measured plasma caffeine concentration following caffeinated bar consumption; however, absorption and delivery likely mimic that of coffee or caffeine anhydrous capsule consumption.

While caffeinated bars are commonly found in the market, research on caffeinated bars is scarce. To date, only one study [ 82 ] Table 7 has examined the effects of a caffeine bar on exercise performance. Furthermore, cyclists significantly performed better on complex information processing tests following the time trial to exhaustion after caffeine bar consumption when compared to the carbohydrate only trial.

As there is not much data to draw from, future work on this source of caffeine is needed. A review by Trexler and Smith-Ryan comprehensively details research on caffeine and creatine co-ingestion [ 32 ]. With evidence to support the ergogenic benefits of both creatine and caffeine supplementation on human performance—via independent mechanisms—interest in concurrent ingestion is of great relevance for many athletes and exercising individuals [ 32 ].

While creatine and caffeine exist as independent supplements, a myriad of multi-ingredient supplements e. It has been reported that the often-positive ergogenic effect of acute caffeine ingestion prior to exercise is unaffected by creatine when a prior creatine loading protocol had been completed by participants [ , ].

However, there is some ambiguity with regard to the co-ingestion of caffeine during a creatine-loading phase e. While favorable data exist on muscular performance outcomes and adaptations in individuals utilizing multi-ingredient supplements e.

Until future investigations are available, it may be prudent to consume caffeine and creatine separately, or avoid high caffeine intakes when utilizing creatine for muscular benefits [ ]. This is likely due to the heterogeneity of experimental protocols that have been implemented and examined.

Nonetheless, a systematic review and meta-analysis of 21 investigations [ ] concluded the co-ingestion of carbohydrate and caffeine significantly improved endurance performance when compared to carbohydrate alone.

However, it should be noted that the magnitude of the performance benefit that caffeine provides is less when added to carbohydrate i.

carbohydrate than when isolated caffeine ingestion is compared to placebo [ ]. Since the publication [ ], results remain inconclusive, as investigations related to sport-type performance measures [ 83 , , , , , , ], as well as endurance performance [ 84 , , ] continue to be published.

Overall, to date it appears caffeine alone, or in conjunction with carbohydrate is a superior choice for improving performance, when compared to carbohydrate supplementation alone. Few studies to date have investigated the effect of post-exercise caffeine consumption on glucose metabolism [ , ].

While the delivery of exogenous carbohydrate can increase muscle glycogen alone, Pedersen et al. In addition, it has been demonstrated that co-ingestion of caffeine with carbohydrate after exercise improved subsequent high-intensity interval-running capacity compared with ingestion of carbohydrate alone.

This effect may be due to a high rate of post-exercise muscle glycogen resynthesis [ ]. Practically, caffeine ingestion in close proximity to sleep, coupled with the necessity to speed glycogen resynthesis, should be taken into consideration, as caffeine before bed may cause sleep disturbances.

The genus of coffee is Coffea , with the two most common species Coffea arabica arabica coffee and Coffea canephora robusta coffee used for global coffee production.

While coffee is commonly ingested by exercising individuals as part of their habitual diet, coffee is also commonly consumed pre-exercise to improve energy levels, mood, and exercise performance [ 11 , 40 ]. Indeed, a recent review on coffee and endurance performance, reported that that coffee providing between 3 and 8.

Specifically, Higgins et al. Since the release of the Higgins et al. review, three additional studies have been published, examining the effects of coffee on exercise performance. Specifically, Niemen et al. Fifty-km cycling time performance and power did not differ between trials.

Regarding resistance exercise performance, only two studies [ 55 , 56 ] have been conducted to date. One study [ 56 ] reported that coffee and caffeine anhydrous did not improve strength outcomes more than placebo supplementation. On the other hand, Richardson et al. The results between studies differ likely because it is challenging to standardize the dose of caffeine in coffee as differences in coffee type and brewing method may alter caffeine content [ ].

Even though coffee may enhance performance, due to the difficulty of standardizing caffeine content most sport dietitians and nutritionists use anhydrous caffeine with their athletes due to the difficulty of standardizing caffeine content.

Consumption of energy drinks has become more common in the last decade, and several studies have examined the effectiveness of energy drinks as ergogenic aids Table 8. Souza and colleagues [ ] completed a systematic review and meta-analysis of published studies that examined energy drink intake and physical performance.

Studies including endurance exercise, muscular strength and endurance, sprinting and jumping, as well as sport-type activities were reviewed. It has been suggested that the additional taurine to caffeine containing energy drinks or pre-workout supplements, as well as the addition of other ergogenic supplements such as beta-alanine, B-vitamins, and citrulline, may potentiate the effectiveness of caffeine containing beverages on athletic performance endeavors [ ].

However, other suggest that the ergogenic benefits of caffeine containing energy drinks is likely attributed to the caffeine content of the beverage [ ].

For a thorough review of energy drinks, consider Campbell et al. Table 8 provides a review of research related to energy drinks and pre-workout supplements. Caffeine in its many forms is a ubiquitous substance frequently used in military, athletic and fitness populations which acutely enhance many aspects of exercise performance in most, but not all studies.

Supplementation with caffeine has been shown to acutely enhance many aspects of exercise, including prolonged aerobic-type activities and brief duration, high-intensity exercise. The optimal timing of caffeine ingestion likely depends on the source of caffeine.

Studies that present individual participant data commonly report substantial variation in caffeine ingestion responses. Inter-individual differences may be associated with habitual caffeine intake, genetic variations, and supplementation protocols in a given study.

Caffeine may be ergogenic for cognitive function, including attention and vigilance. Caffeine at the recommended doses does not appear significantly influence hydration, and the use of caffeine in conjunction with exercise in the heat and at altitude is also well supported.

Alternative sources of caffeine, such as caffeinated chewing gum, mouth rinses, and energy gels, have also been shown to improve performance.

Energy drinks and pre-workouts containing caffeine have been demonstrated to enhance both anaerobic and aerobic performance. Individuals should also be aware of the side-effects associated with caffeine ingestion, such as sleep disturbance and anxiety, which are often linearly dose-dependent.

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Perkins R, Williams MH. Effect of caffeine upon maximal muscular endurance of females. Durrant KL. This article explains how creatine can improve your exercise….

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Medically reviewed by Angela M. Bell, MD, FACP — By Brian Krans — Updated on February 5, Safe ergogenic dietary supplements.

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Actoprotectors are distinct from other doping compounds in that they increase physical and psychological resilience via non-exhaustive action. Actoprotectors such as bemethyl and bromantane have been used to prepare athletes and enhance performance in Olympic competition.

Nootropics, or "cognition enhancers", are substances that are claimed to benefit overall cognition by improving memory e. Allows performance beyond the usual pain threshold.

Some painkillers raise blood pressure , increasing oxygen supply to muscle cells. Painkillers used by athletes range from common over-the-counter medicines such as NSAIDs such as ibuprofen to powerful prescription narcotics.

Sedatives and anxiolytics are used in sports like archery which require steady hands and accurate aim, and also to overcome excessive nervousness or discomfort for more dangerous sports. Diazepam , nicotine, and propranolol are common examples. Ethanol , the most commonly used substance by athletes, can be used for cardiovascular improvements though has significant detrimental effects.

Ethanol was formerly banned by WADA during performance for athletes performing in aeronautics, archery, automobile, karate, motorcycling and powerboating, but was taken off the ban list in It is detected by breath or blood testing. Cannabis is banned at all times for an athlete by WADA, though performance-enhancing effects have yet to be studied.

Cannabis and nicotine are detected through urine analysis. Blood doping agents increase the oxygen-carrying capacity of blood beyond the individual's natural capacity.

Recombinant human erythropoietin rhEPO is one of the most widely known drugs in this class. Erythropoietin, or EPO, is a hormone that helps increase the production of red blood cells which increases the delivery of oxygen to muscles.

Gene doping agents are a relatively recently described class of athletic performance-enhancing substances. Also known as anabolic steroid precursors, they promote lean body mass.

While the use of PEDs has expanded in recent times, the practice of using substances to improve performance has been around since the Ancient Olympic Games. were used by the Roman Gladiators to overcome injuries and fatigue.

In the late 19th century as modern medicine and pharmacology were developing, PEDs saw an increase in use. In the 20th century, testosterone was isolated and characterized by scientists.

In the s, the main PEDs were cortisone and anabolic steroids. Adolescents are the most vulnerable group when it comes to taking performance-enhancing substances.

In sports, the term performance-enhancing drugs is popularly used in reference to anabolic steroids or their precursors hence the colloquial term "steroids" ; anti-doping organizations apply the term broadly. When medical exemptions are granted they are called therapeutic use exemptions.

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Download as PDF Printable version. Substance used to improve any form of activity performance in humans. Main article: Anabolic steroid. Main article: Stimulant. Main articles: Human growth hormone , Creatine , and Beta-Hydroxy-Beta-methylbutyrate.

Main article: Adaptogen. Main article: Actoprotector. Main article: Nootropic. Main article: Analgesic. Main articles: Sedative and Anxiolytic. Main article: Blood doping. Main article: Erythropoietin. Main article: Gene doping. Main article: Prohormone.

Main article: Doping in sport. May doi : PMC PMID Primary Care. Amphetamines and caffeine are stimulants that increase alertness, improve focus, decrease reaction time, and delay fatigue, allowing for an increased intensity and duration of training Current Neuropharmacology.

The first aim of this paper was to review current trends in the misuse of smart drugs also known as Nootropics presently available on the market focusing in detail on methylphenidate, trying to evaluate the potential risk in healthy individuals, especially teenagers and young adults.

Better Fighting Through Chemistry?

Performance-enhancing substancesalso perfrmance Physical performance enhancement performance-enhancing drugs PEDsConcentration and focus in a digital age are substances that are used to improve any form Physical performance enhancement activity performance in humans. Perfotmance well-known example of enhandement in sports Physical performance enhancement doping in sportwhere banned physical performance-enhancing drugs are used by athletes and bodybuilders. Athletic performance-enhancing substances are sometimes referred as ergogenic aids. Performance-enhancing substances are also used by military personnel to enhance combat performance. The use of performance-enhancing drugs spans the categories of legitimate use and substance abuse. The classifications of substances as performance-enhancing substances are not entirely clear-cut and objective.

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