More Proof That Caffeine Boosts Athletic Performance

UK scientists show for the first time that high doses of caffeine directly increase muscle power and endurance during relatively low-intensity activities.

New research shows increased muscle performance in sub-maximal activities, which in humans can range from everyday activities to running a marathon. With no current regulations in place, the scientists from Coventry University believe their findings may have implications for the use of caffeine in sport to improve performance.

The scientists present their work at the Society for Experimental Biology Annual Meeting in Prague.
"A very high dosage of caffeine, most likely achieved via tablets, powder or a concentrated liquid, is feasible and might prove attractive to a number of athletes wishing to improve their athletic performance," explains lead researcher, Dr Rob James.

"A small increase in performance via caffeine could mean the difference between a gold medal in the Olympics and an also-ran," he added.

Caffeine is not currently listed by the World Anti-Doping Agency (WADA) as a banned substance at any concentration in blood or urine samples. Before 2004 WADA did set a specific level over which athletes could be banned, but this restriction was removed.  Muscle activity is divided into maximal, where the muscles are pushed to full capacity such as in sprinting or weight lifting, and sub-maximal, which covers all other activities.

A member of the team, Jason Tallis, tested the effect of caffeine on both the power output and endurance of soleus muscles (lower leg muscle) in mice, under both maximal and sub-maximal activities.

He found that a caffeine dosage of 70 µM enhanced power output by ~6% during both types of activity. This effect in humans is likely to be very similar, according to the researchers.

"70 μM caffeine concentration is the absolute maximum that can normally achieved in the blood plasma of a human, however concentrations of 20-50 μM are not unusual in people with high caffeine intakes," explains Dr James.

Resultant caffeine in blood plasma (70μM maximum) may act at receptors on skeletal muscle causing enhanced force production. Scientists already know that ingestion of caffeine can increase athletic performance by stimulating the central nervous system.  Additionally, 70μM caffeine treatment increased endurance during sub-maximal activity, but significantly reduced endurance during maximal activity.

Source: Society for Experimental Biology

See also: Starbucks' Secret Sports Supplement and How Should Cheating Be Defined In Sports?

The Mechanics Of Steroids

A $252 million contract to play baseball causes "an enormous amount of pressure ... to perform at a high level every day," according to Alex Rodriguez. The New York Yankees' third baseman provided a few more details last week about the anabolic steroids he used from 2001 to 2003 after he had signed a record-setting deal with his former team, the Texas Rangers.

Here is what most of us know about anabolic steroids: they make muscles grow faster, there are harmful side effects to our health, most sports leagues have banned them, and they are illegal without a prescription.

But how do they actually work? Does an athlete just pop a few pills and then wait for the Popeye-spinach effect? Let's dig a little deeper into the science of steroids.

Legal uses
Anabolic steroids, or anabolic-androgenic steroids (AAS), are the synthetic (made in a lab) derivatives of the naturally produced hormone testosterone. They promote the growth of muscle (anabolic effect) and the typical male characteristics of puberty (androgenic effect).

When legally prescribed, they are an option for patients who produce abnormally low levels of testosterone or who suffer from body-wasting diseases such as cancer or AIDS. When used by athletes, the goal is to speed up the body's natural muscle-building process.

When we lift weights heavier than what we're used to, we create tiny micro-tears in muscle fibers. The body's natural repair process repairs the tear and then overcompensates by adding bigger cells to build a stronger fiber — this is called muscular hypertrophy. Over time, this repeated process of teardown and re-build will result in muscle growth.

Natural testosterone is the body's main ingredient for this process, but anabolic steroids can serve as a supplement.

Once ingested, an AAS travels through the blood stream to the muscle tissue. It is drawn into the muscle cell's receiving dock, called an androgen receptor. Once delivered to the muscle cell, the steroid can interact with the cell's DNA and stimulate the protein synthesis process that promotes cell growth.

Different variants and amounts of AAS can cause different reactions producing either massive body-building physiques or more toned athletic muscles (i.e. Barry Bonds vs. A-Rod). Athletes experiment with different combinations (called stacking) or regimens (pyramiding) in an attempt to fine-tune the final result.  A-Rod's stack was reportedly straight testosterone and Primobolan.

Beyond bulk
While the focus in the media is on the bulked-up home run hitters, anabolic steroids can also benefit pitchers and others who need a faster turnaround from sore, overused muscles. Intense exercise also releases cortisol, known as the stress hormone, which breaks down muscle tissue, producing sore muscles.

AAS can block cortisol from binding to the muscle cell's receptor sites, which diminishes the breakdown process. Less muscle breakdown means less muscle fatigue which would allow a pitcher to recover more quickly from a nine-inning outing.

Besides all of the known negative side effects of using steroids just for ergogenic reasons, there is also the uncertainty of what exactly you are taking. Last month, federal Drug Enforcement Administration agents arrested the owners of an Alabama-based online pharmacy on charges that they filled hundreds of illegal prescriptions for anabolic steroids for clients across the country.

The worst news for the customers of this pharmacy was delivered by U.S. Attorney Deborah Rhodes: "Each of the pharmacy owners and pharmacists named in the indictment are charged with prescribing and selling veterinary steroids, approved for cattle and livestock only, to humans." 

Please visit my other sports science articles at LiveScience.com

How Should Cheating Be Defined In Sports?

When Milwaukee Brewers pitcher Chris Capuano reports for spring training in April, he will be anxious to demonstrate the effects of a performance-enhancing off-season. His brain will benefit from a sharper focus while his throwing arm will boast an extra boost that has been missing since 2006. Stimulants? Steroids? Scandal? No need to panic, he just had LASIK surgery for his eyes and "Tommy John" surgery for his injured elbow. Of course, had he chosen amphetamines to improve his focus or steroids to increase his strength, he would have been banned and berated. 

Society Decides

There is confusion over the means and methods athletes have available to enhance their performance. Certainly, corrective eye surgery to raise your vision level to 20/20 seems fair, but many athletes go into the procedure hoping to come out with enhanced 20/15 or 20/10 eyesight. Replacing a damaged elbow ligament with a tendon doesn't seem like cheating, but what if its done on a healthy elbow hoping for a few more miles per hour on a fastball that has faded over the years?

Earlier this month, a commentary in the journal Nature recommended a fresh look at cognitive-enhancing drugs and where to draw the line in the sand between natural performance and enhanced performance. The authors, an esteemed group of neuroscientists and ethicists, argued that "enhanced" is only defined by the rules set by society.

Certainly, abuse of prescription drugs, such as Ritalin and Adderall, is illegal because of the potential, harmful side effects. Still, reports of the rising use of these drugs by college students and professionals show the demand for options beyond nutrition, exercise and sleep.

These drugs are just the first generation of possible brain boosting supplements, which is why the Nature commentators are calling for an organized, stigma-free approach to evaluating the risks, benefits and ethics of future products.

Even in Major League Baseball, there is mounting evidence that cognitive-enhancing drugs may be on the rise. Since MLB banned amphetamines in 2006, there has been a dramatic rise in the number of therapeutic use exemptions issued to players for attention-deficit disorder diagnoses, for which drugs like Ritalin and Adderall can be legitimately prescribed. In 2006, 28 players applied for the exemption, while a year later there were 103. There is suspicion that many of these ADD diagnoses are just excuses to get the pills.

Legal Jolt

So, what if there was a cognitive-enhancing, sports supplement that increased alertness, concentration, reaction time and focus while also decreasing the perception of muscle fatigue? Even more encouraging, this supplement is sold in millions of outlets and is socially accepted worldwide. It comes in three sizes, tall, grande or venti – coffee. More specifically, caffeine has been the subject of many recent studies of its effectiveness, both cognitively and physiologically.

Earlier this year, Dr. Carrie Ruxton completed a literature survey to summarize 41 double-blind, placebo-controlled trials published over the past 15 years to establish what range of caffeine consumption would maximize benefits and minimize risk for cognitive function, mood, physical performance and hydration. The studies were divided into two categories, those that looked at the cognitive effects and those that looked at physical performance effects.

The results concluded that there was a significant improvement in cognitive functions like attention, reaction time and mental processing as well as physical benefits described as increased "time to exhaustion" and decreased "perception of fatigue" in cycling and running tests.

Given these results, how exactly does caffeine perform these wonderful tricks? Dr. Ruxton explains from the study, "Caffeine is believed to impact on mood and performance by inhibiting the binding of both adenosine and benzodiazepine receptor ligands to brain membranes. As these neurotransmitters are known to slow down brain activity, a blockade of their receptors lessens this effect."

Bottom line, the chemicals in your brain that would cause you to feel tired are blocked, giving you a feeling of ongoing alertness. This pharmacological process is very similar to that of the ADD drugs.

If caffeine is such a clear cut performance enhancing supplement, why did the World Anti-Doping Agency (WADA) first add caffeine to its banned substance list, only to remove it in 2004? At the time that it was placed on the banned list, the threshold for a positive caffeine test was set to a post-exercise urinary caffeine concentration of about 3-4 cups of strong coffee.

However, more recent research has shown that caffeine has ergogenic effects at levels as low as the equivalent of 1-2 cups of coffee. So, it was hard for WADA to know where to draw the line between athletes just having a few morning cups of coffee/tea and those that were intentionally consuming caffeine to increase their performance level.

So, if Chris Capuano has a double espresso before pitching, his brain, eyes and arm should enhance his performance in the game.  Is that an unfair advantage? Science will continue to offer new and improved methods for raising an athlete's game above the competition. Players, league officials and fans will have to decide where to draw the line.

Please visit my other articles on Livescience.com

Starbucks' Secret Sports Supplement

For an athlete, it seems to good to be true. A "sports supplement" that increases alertness, concentration, reaction time and focus while decreasing muscle fatigue or at least the perception of fatigue. It can even shorten recovery time after a game. HGH? EPO? Steroids? Nope, just a grande cup of Juan Valdez's Best, Liquid Lightning, Morning Mud, Wakey Juice, Mojo, Java, aka coffee. Actually, the key ingredient is caffeine which has been studied repeatedly for its ergogenic (performance-enhancing) benefits in sports, both mentally and physically. Time after time, caffeine proves itself as a relatively safe, legal and inexpensive boost to an athlete.

Or does it? If caffeine is such a clear cut performance enhancing supplement, why did the World Anti-Doping Agency (WADA), who also monitors this month's Beijing Olympics for the International Olympic Committee (IOC), first add caffeine to its banned substance list, only to remove it in 2004? At the time that it was placed on the banned list, the threshold for a positive caffeine test was set to a post-exercise urinary caffeine concentration of 12 µg/ml (about 3-4 cups of strong coffee). However, more recent research has shown that caffeine has ergogenic effects at levels as low as the equivalent of 1-2 cups of coffee. So, it was hard for WADA to know where to draw the line between athletes just having a few morning cups of coffee/tea or maybe some chocolate bars and athletes that were intentionally consuming caffeine to increase their performance level. However, caffeine is still on the WADA monitoring list as a substance to screen for and watch for patterns of use.


Meanwhile, athletes are still convinced that caffeine helps them.
In a recent survey from Liverpool John Moores University, 480 athletes were interviewed about their caffeine use. One third of track and field athletes and 60% of cyclists reported using caffeine specifically to give them a boost in competition. In addition, elite-level athletes interviewed were more likely to rely on caffeine than amateurs. Dr. Neil Chester, co-leader of the study, commented about the confusion created by the WADA status change for caffeine, "There's been a lack of communication from WADA and there is a question about whether or not sporting authorities are condoning its use. Ultimately there is a need to clarify the use of caffeine within the present anti-doping legislation."

So, have athletes found a loophole to exploit that gives them an edge? Dr. Carrie Ruxton recently completed a literature survey to summarize 41 double-blind, placebo-controlled trials published over the past 15 years to establish what range of caffeine consumption would maximize benefits and minimize risk for cognitive function, mood, physical performance and hydration. The studies were divided into two categories, those that looked at the cognitive effects and those that looked at physical performance effects. The results concluded that there was a significant improvement in cognitive functions like attention, reaction time and mental processing as well as physical benefits described as increased "time to exhaustion" and decreased "perception of fatigue" in cycling and running tests. Longer, endurance type exercise showed greater results than short-term needs for energy.

Given these results, how exactly does caffeine perform these wonderful tricks? Dr. Ruxton explains from the study, "Caffeine is believed to impact on mood and performance by inhibiting the binding of both adenosine and benzodiazepine receptor ligands to brain membranes. As these neurotransmitters are known to slow down brain activity, a blockade of their receptors lessens this effect. " Bottom line, the chemicals in your brain that would cause you to feel tired are blocked, giving you a feeling of ongoing alertness. Your body still needs the sleep, caffeine just delays the feeling of being tired.

As to the physiological benefits, caffeine has also been shown to stimulate the release of fat into the bloodstream. The early conclusion was that the increased free fatty acids in the blood would allow our muscles to use fat as fuel and spare glycogen (carbohydrates) allowing us to exercise longer. Another theory is that caffeine stimulates the central nervous system reducing our perception of effort so that we feel that we can continue at an increased pace for longer periods.

The discussion on glycogen has recently taken another interesting twist; caffeine's apparent ability to replenish glycogen (the body's primary fuel source) more rapidly after an intense workout. A team at the Garvan Institute for Medical Research has found that athletes who consumed a combination of carbohydrates and caffeine following an exhaustive exercise had 66% more glycogen in their muscles four hours later, compared to when they consumed carbohydrates alone. 

They asked cyclists to pedal to exhaustion in the lab, then gave them a drink that contained either carbohydrates with caffeine or just carbohydrates (the cyclists did not know which drink they were getting). They repeated the process 7-10 days later and reversed the groups. Muscle biopsies and blood samples were tested for levels of glycogen after each trial period. The researchers did not have an explanation for the increased levels of glycogen resulting from the caffeine-spiked juice. One theory is the higher circulating blood glucose and plasma insulin levels caused by the caffeine were key factors. In addition, caffeine may increase the activity of several signaling enzymes, including the calcium-dependent protein kinase and protein kinase B (also called Akt), which have roles in muscle glucose uptake during and after exercise.

So, before you start drinking the Starbucks by the gallon, here are some guidelines. You can consume 2-2.5 mg of caffeine per pound of body weight daily to achieve its ergogenic effects. This equates to 250-312 mg for a 125-pound woman and 360-450 mg for a 180-pound man. More is not better, as other research has shown a decline in benefit and an increase in caffeine's side effects beyond this level. One "grande" cup (16 oz.) of Starbucks coffee contains about 320-500 mg of caffeine, while a 12 oz. can of soda will provide 35-70 mg of caffeine. Maybe we'll see the ultimate sports drink soon, kind of like Monster meets Gatorade... wait, its already here: Lucozade Sport with Caffeine Boost!







C. H. S. Ruxton (2008). The impact of caffeine on mood, cognitive function, performance and hydration: a review of benefits and risks Nutrition Bulletin, 33 (1), 15-25 DOI: 10.1111/j.1467-3010.2007.00665.x

N. Chester, N. Wojek (2008). Caffeine Consumption Amongst British Athletes Following Changes to the 2004 WADA Prohibited List International Journal of Sports Medicine, 29 (6), 524-528 DOI: 10.1055/s-2007-989231

D. J. Pedersen, S. J. Lessard, V. G. Coffey, E. G. Churchley, A. M. Wootton, T. Ng, M. J. Watt, J. A. Hawley (2008). High rates of muscle glycogen resynthesis after exhaustive exercise when carbohydrate is coingested with caffeine Journal of Applied Physiology, 105 (1), 7-13 DOI: 10.1152/japplphysiol.01121.2007

HGH - Human Growth Hoax?

Athletes, both professional and amateur, as well as the general public are convinced that human growth hormone (HGH), Erythropoietin (EPO) and anabolic-androgenic steroids (AAS) are all artificial and controversial paths to improved performance in sports.  The recent headlines that have included Barry Bonds, Marion Jones, Floyd Landis, Dwayne Chambers, Jose Canseco, Jason Giambi, Roger Clemens and many lesser known names (see the amazingly long list of doping cases in sport) have referred to these three substances interchangeably leaving the public confused about who took what from whom.  With so many athletes willing to gamble with their futures, they must be confident that they will see significant short-term results.  

So, is it worth the risk?  Two very interesting recent studies provide some answers on at least one of the substances, HGH.


A team at the Stanford University School of Medicine, led by Hau Liu MD, recently reviewed 27 historical studies on the effects of HGH on athletic performance, dating back to 1966 (see reference below).  They wanted to see if there were any definitive links between HGH use and improved results.  In some of the studies, test volunteers who received HGH did develop more lean body mass, but also developed more lactate during aerobic testing which inhibited rather than helped performance.  While their muscle mass increased, other markers of athletic fitness, such as VO2max remained unchanged.  “The key takeaway is that we don’t have any good scientific evidence that growth hormone improves athletic performance,” said senior author Andrew Hoffman, MD, professor of endocrinology, gerontology and metabolism.



Both Liu and Hoffman cautioned that the amounts of HGH given to these test subjects may be much lower than the the purported levels claimed to be taken by professional athletes.  They also pointed out that at a professional level, a very slight improvement might be all that is necessary to get an edge of your opponent.  Hoffman also added an insightful comment, “So much of athletic performance at the professional level is psychological.”  If an athlete takes HGH, sees some muscle mass growth and isn't 100% sure of its performance capabilities, might he assume he now has other "Superman" powers?



That is exactly the premise that a research team from Garvan Institute of Medical Research in Sydney, Australia used to find out if HGH users simply relied on a placebo effect.  Sixty-four participants, young adult recreational athletes, were divided into two groups of 32 and tested for a baseline of athletic ability in endurance, strength, power and sprinting.  One group received growth hormone and the other group received a simple placebo.  It was a "double-blind" study in that neither the participants nor the researchers knew during the testing which substance each group received.



At the end of the 8 week treatment, the athletes were asked if they thought they were in the HGH group or the placebo group.  Half of the group that had received the placebo incorrectly guessed that they were on HGH.  Not too surprisingly, the majority of the "incorrect guessers" were men.  Here's where it gets interesting.  The incorrect guessers also thought that their athletic abilities had improved over the 8 week period.  The team retested all of the placebo group and actually did find improvement across all of the tests, but only significantly in the high-jump test.


Jennifer Hansen, a nurse researcher and Dr. Ken Ho, head of the pituitary research unit at Garvan have not released the data on the group that did receive the HGH, but they will in their final report coming soon.



So, let's recap.  On the one hand, we have a research review that claims there is not yet any scientific evidence that HGH actually improves sports performance.  Yet, we have hundreds, if not thousands, of athletes illegally using HGH for performance gain.  Showing the effect of the "if its good enough for them, its good enough for me" beliefs of the public regarding professional athlete use of HGH, we now have research that shows even those who received a placebo, but believed they were taking HGH not only thought they were improving but actually did improve a little.  Once again, we see the power of our own natural, non-supplemented brain to convince (or fool) ourselves to perform at higher levels than we thought possible.








Liu, H., Bravata, D.M., Olkin, I., Friedlander, A., Liu, V., Roberts, B., Bendavid, E., Saynina, O., Salpeter, S.R., Garber, A.M. (2008). Systematic review: the effects of growth hormone on athletic performance.. Annals of Internal Medicine, 148(10), 747-758.