Monday, August 15, 2011

Caffeine and running: effectiveness, ethics, and the NCAA

In my previous post, I mentioned how caffeine can boost athletic performance by stimulating the central nervous system, which in turn makes a given effort seem easier–the rated perceived exertion (RPE) drops.  I was leading you on a bit: the drop in RPE isn't the whole story with caffeine.  In fact, it only accounts for about 30% of the performance boost that comes from using caffeine.  I've received recieved a few questions specifically about caffeine since then, so today I'm going to go in-depth on the ins and outs of caffeine as an ergogenic (perfomance-boosting) aid.  This article is fairly thorough, since you can encounter a lot of myths about caffeine and sport on the web.  One site will claim "to fail the NCAA's drug test, you'd have to drink twelve cups of coffee in two hours" (page 10, I'm not making this up) while another will claim "just a cup or two of coffee or one energy drink can cause you to fail your drug test!"  I'd like to clear up some of that confusion.  To do so, there's a bit of math ahead–if you find yourself over your head, skip ahead to the next bolded sentence–that's the important stuff. 

Introduction

Caffeine might just be the "world's greatest drug."  It's certainly the world's most popular.  In the United States alone, 90% of the population consumes caffeine in some form every day.  Worldwide, billions of people consume caffeine on a regular basis.  By all definitions, caffeine is a psychoactive substance, and like all drugs, it has several effects (good and bad) that occur with different doses.

 The negative effects of caffeine at high doses include headaches, difficulty sleeping, tremors, and irritability.  It increases urine production, although regular caffeine users rapidly become immune to this effect.  The "caffeine causes dehydration" myth has persisted for a long time, but it is simply not true.  In massive doses, caffeine can cause seizures and death. Additionally, withdrawal in heavy users can cause headaches, drowsiness, and insomnia, and may persist for up to five days. 

However, it has a very large therapeutic index–the ratio of the toxic dose to the effective dose.  And its benefits are manifold at doses far below those that cause negative effects.  Caffeine boosts mood, alertness, vigilance, and cognitive function.  In an excellent 2008 review of double-blind, placebo-controlled trials, C.H.S. Ruxton concluded:

"From a review of double-blind, placebo-controlled studies published over the past 15 years, it would appear that the range of caffeine intake that could maximise benefit and minimise risk in relation to mood, cognitive function, performance and hydration is 38 to 400 mg per day, equating to 1 to 8 cups of tea, or 0.3 to 4 cups of brewed coffee per day. Current levels of caffeine intake in the UK fall well within this range, suggesting that risk, for example from dehydration, is likely to be minimal."
In a different review, A. Smith concluded that "Regular caffeine usage appears to be beneficial, with higher users having better mental functioning. [...] The evidence clearly shows that levels of caffeine consumed by most people have largely positive effects on behavior."

So even fairly heavy users of caffeine are safe from its negative effects and will reap the benefits of its boost to cognitive performance.  But caffeine also has an effect on athletic performance–a very pronounced one in the case of endurance events.  In a 2005 meta-analysis, M. Doherty and P. M. Smith wrote,

"In comparison to placebo, caffeine also improved performance by approximately 11%, a finding that concurs with another recent meta-analysis of the effects of caffeine on exercise test outcome (Doherty & Smith, 2004). As RPE was lower during exercise but unchanged at the end of exhausting exercise, it may be that part of the explanation for the improvement in performance has to do with a dampening of the perceptual response during exercise. Indeed, our regression analysis revealed that RPE during exercise could explain nearly one-third of the variation in the subsequent improvement in performance." [emphasis added]
Eleven percent is a whole heck of a lot.  And Doherty and Smith's review is only one in a litany of papers that report the benefits of caffeine on endurance exercise.  Away from the lab, for a recreational athlete, the boost will be more like 5%, according to Dr. Mark Tarnopolsky of McMaster University in Canada.  But even then–five percent is the difference between 16:00 and 15:12 in the 5k.  Often, ergogenic aids boost the performance of recreational athletes much more than elites, so perhaps a top-flight athlete wouldn't benefit as much.  But according to Matt Fitzgerald (who didn't cite it, tsk tsk) a treadmill study of elite runners still found a 1.9% increase in time to exhaustion.  Putting that in perspective, 1.9% is the difference between a 4:30 and 4:25 mile.  How does this happen? Is it legal? Is it right?



Understanding Dosages

To understand the effects of caffeine, we need a firm grasp on some simple pharmacology.  Most drugs have a dose-dependent effect–an effect which varies based on how much of it is consumed.  Pharmacologists control for body size by expressing dosage in mg/kg: milligrams of a drug consumed per kilogram of body weight.  So, a child who weighs 40 kg (about 90 pounds) only needs half the dose given to an 80 kg man to achieve the same effect.  In the real world, however, drugs come in absolute amounts, so we need to do a bit of math to get meaningful results.  If we have a hypothetical runner who weighs 60 kg (132 lbs, a bit less than I weight) who consumes 400 mg of ibuprofen (Advil) for a headache, he has taken a dose of 6.67 mg/kg.

We'll be using much of the same math for caffeine.  For reference, here is the absolute amount of caffeine in various sources, natural and artificial:

One cup (6 fl. oz.) green tea: 30 mg
One cup (6 fl. oz.) black tea: 50 mg
One cup (7 fl. oz.) drip coffee: 115-175 mg (~145 average)
One shot (2 fl. oz.) espresso: 100 mg
One bar (1.5 oz) dark chocolate: 31 mg
One can (12 oz) Coco-Cola: 34 mg
One can (12 oz) Mountain Dew: 54 mg
One tablet, No Doz maximum strength: 200 mg

Once inside the body, caffeine is distributed out into the various tissues and fluids of your body.  However, only the portion of the drug that is in your bloodstream will have the intended effect.  The ibuprofen milling around in the gall bladder won't help our runner's headache very much.  Pharmacologists use a term called the volume of distribution to calculate what dosage of a drug will produce the desired blood plasma concentration.   The volume of distribution is termed VD and is expressed in terms of liters per kilogram of body weight. In short, it relates the amount of drug in the body to the concentration of the drug in the blood plasma.

The two are related as follows: 

VD = (Amount of drug in body) / (plasma concentration of blood) ÷ body weight

So, for our 60 kg runner who takes 400 mg ibuprofen, we might take a blood sample after 45 minutes, once the drug has been completely absorbed.  Let's say that the blood sample shows a plasma concentration of 48 milligrams of ibuprofen per liter of blood (mg/L). Running some numbers, the volume of distribution turns out to be:

VD = (400 mg) / (48 mg/L) ÷60 kg
      =  0.14 L/kg


Now that we know the volume of concentration, we can use it to calculate how much of a specific drug (in this case, ibuprofen) we need to administer to achieve a desired plasma concentration.  So for a 100 kg shot putter, if we want the same blood concentration, we can easily calculate it using VD.

Finally, most drugs are eliminated from the body in an exponentially-decaying fashion.  Hence, they have an elimination half-life.  This is the amount of time it takes for the concentration of the drug to drop by 50%.  So taking our 60 kg runner who has consumed 400 mg ibuprofen (dose of 6.67 mg/kg), we can calculate the drop in the effective dosage over time given that ibuprofen has a half-life of about 2 hours.  So two hours after the peak in ibuprofen levels in the body, the effective dose is halved to 3.33 mg/kg.  After another two hours, it is halved again to 1.66 mg/kg.  This continues until the drug is below detectable limits.

The Research
The research reviewed by Ruxton and Dohert & Smith uses dosages from 3-9 mg/kg of caffeine, almost always administered 60 minutes before the exercise test. 3-6 mg/kg is a "moderate" dosage, 9 mg/kg is a "high" dose.  Most studies used 5-7 mg/kg.  For our hypothetical 60 kg runner, let's run some math:

3 mg/kg = 180 mg caffeine = 3.6 cups of black tea, 1.25 cups of drip coffee, 1.8 shots of espresso, or 0.87 No Doz tablets.
6 mg/kg =  360 mg caffeine = 7.2 cups of black tea,  2.5 cups of coffee, 3.6 shots of espresso, or 1.8 No Doz tablets
9 mg/kg = 540 mg caffeine = 10.8 cups of black tea, 3.75 cups of coffee, 5.4 shots of espresso, or 2.7 No Doz tablets

Reviewing this, it's easy to see that many people could easily find themselves with a "moderate" dose of caffeine without even realizing it.  Overfilling your morning coffee cup by a bit will give our 60 kg runner a research-caliber caffeine dosage. Achieving a "high" dosage of caffeine, however, requires a more determined effort for most people, excluding habitual coffee drinkers, to whom 4 cups of coffee is no big deal.

But higher doses don't seem to be necessary to achieve a boost in performance.  In a 2008 review, Louise M. Burke states, "Several studies suggest there is no dose-response relationship between caffeine intake and benefits to endurance exercise or, if a dose-response exists, there is a plateau at ~3 mg/kg."  Translation: doses above 3 mg/kg do not seem to confer an additional benefit. The main mechanism by which caffeine stimulates increased performance in shorter events seems to be by stimulating the central nervous system.  Once the CNS is "primed," it seems that more caffeine doesn't have an additional effect on performance.


Caffeine Metabolism and Excretion

Once consumed, what happens to caffeine? Whether it is consumed in tablet or liquid form, caffeine is absorbed through the stomach and small intestine.  It reaches the bloodstream within 15 minutes, and caffeine levels in the blood peak at about 60-90 minutes post-ingestion.  Like most drugs, caffeine is broken down by the liver.  However, here is our first road bump: caffeine has a highly variable elimination half-life.  For the average healthy adult, it is 4.9 hours.  But this can range from 2 to 12 hours! This is mostly because the metabolic clearance rate, the speed at which the liver and kidneys remove caffeine from the bloodstream, can vary by a factor of 3 to 15 from person-to-person.  Further, women on oral contraceptives and women who are pregnant have higher elimination half-lives; 5-10 hours for women on contraceptives, and 9-11 hours for pregnant women.  We will see the implications of this a bit further down the road.

  Caffeine levels in the blood peak between 60 and 90 minutes after ingestion.  From M. Bruce et al. 1986. 1,7-dimethylxanthine is a metabolite that is created when caffeine is broken down by the liver.

When the liver actually processes caffeine, it breaks it down into several different metabolites.  A small amount of caffeine (0.5-3% of a given dose) is excreted directly in urine instead of being broken down by the liver. 

Drug Testing

Caffeine is a regulated (but not completely banned) substance by the NCAA.  It was also regulated by the International Olympic Committee and the World-Anti-Doping Agency as a performance-enhancing substance until 2004.  It is no longer banned by the IOC or WADA, but the NCAA continues to test for and regulate it.  .  Unlike some drug tests which look for metabolites of drugs or hormones taken by an athlete, the test for caffeine is a direct measurement of the concentration of caffeine in the urine. Until the IOC and WADA removed caffeine from the banned substances list, the maximum level allowable in an athlete's urine was 12 mg/L.  The NCAA's current limit is 15 mg/L.  What sort of caffeine dosage is required to exceed the NCAA or IOC/WADA levels of caffeine in urine? And where does this dosage fall relative to the effective dosage required for a performance-boosting effect?

Let's run some math on dosage intake vs. blood concentration.  Birkett and Miners report that the volume of distribution (VD) of caffeine is about 0.5 L/kg.  If our 60 kg runner were to consume 360 mg of caffeine 60 minutes before a race to achieve a peak dosage of 6 mg/kg at race time–above the dosage that produces an ergogenic effect in many studies–we can calculate his predicted peak blood plasma caffeine concentration.

Remember that:

VD = (Amount of drug in body) / (plasma concentration of blood) ÷ body weight

And so,
0.5 L/kg = (360 mg) / (x mg/L) ÷60 kg
solving for x,
blood concentration  = 12 mg/L of caffeine in the blood plasma


The level of caffeine in the blood is the same as the level of caffeine in the urine.  According to Birkett and Miners, plasma caffeine to urine caffeine ratio is, on average, 1.3. This means, to get our predicted urine caffeine concentration, we need to divide by 1.3.

This means our hypothetical runner has a urine caffeine concentration of 9.2 mg/L–below the IOC/WADA and NCAA limit.  Even if we run the math again with a dosage of 540 mg/kg, equal to the "high" dosage of 9 mg/kg caffeine (5.4 espresso shots) used in some of the research, we only come up with 13.8 mg/L in the urine–over the IOC/WADA limit, but under the NCAA limit.  At a "low" dose of 3mg/kg, his predicted urine concentration is 4.6 mg/L.

This is some crude math, though. How do these value compare to the real world? In real life, athletes aren't tested for their urine caffeine levels when they start a race or an endurance test.  They are tested when it's over.  I've collected some data from two separate studies (Graham and Spiet, Pasman et al.) and compared them to our theoretical runner.  Both studies had the subjects undergo an endurance test lasting about 60 minutes, and both studies administered different levels of caffeine to the subjects 60 minutes before the test.  Remember, caffeine levels peak around 60 minutes after ingestion and then drop according to the subject's elimination half life.  To account for the breakdown of some of the caffeine in our predicted values, we need to reduce our prediction by 13%, assuming a half-life of 5 hours (recall that the half-life can vary from 2-12 hours depending on the individual; this would translate into a 29% and 5.6% reduction, respectively).

Caffeine dose Predicted level Experimental level ± SEStudy
5 mg/kg 6.7 mg/L4.8 ± 1.8Pasman et al.
9 mg/kg12.0 mg/L10.0 ± 0.8Graham and Spriet
9 mg/kg12.0 mg/L8.7 ± 1.2Graham and Spriet*
9 mg/kg12.08.9 ± 5.2Pasman et al.
13 mg/kg17.4 mg/L14.9 ± 6.9Pasman et al.
*Graham and Spriet had two separate trials, one running and one cycling, both with the same dosage.

So our rather crude predictions, if anything, are about one or two standard deviations above the experimental mean.  So what's the upshot? We can predict fairly accurately the resultant level of caffeine in urine from an average, healthy individual.  Several other studies, including Cox et al. and Conway et al., have also found it difficult to approach urine caffeine levels in laboratory endurance test settings that violate IOC/WADA or NCAA rules.  But these studies all used a small number of subjects, and testing standards are not and should not be designed for the average athlete–they need to ensure that virtually all athletes are safe from a false positive.  With caffeine, we'll soon see that accomplishing that through a urine or blood test is impossible.

Problems with Testing for Caffeine


Recall that earlier, I mentioned that the elimination half-life of caffeine is highly variable.  In addition to that, it turns out that caffeine blood levels are also highly variable for a given dose, both among a group of people and for a given individual.  Consider a group of regular coffee drinkers.  Let's say they consume a cup of coffee in the morning, a cup of coffee in the afternoon, and a cup of coffee after dinner–one every eight hours.  If we collected their urine during each of those eight-hour stints, between coffee drinks, we'd expect to see the same concentration of caffeine, both day-to-day and person to person, assuming they had similar weights. D. J. Birkett and J. O. Miners did a study with just this premise, except instead of coffee, they administered a 150mg caffeine pill every eight hours.  But their findings, summarized in the table below, were troubling.

I've highlighted two pairs of subjects in red and blue.  Cu is the concentration of caffeine in the 8-hour urine samples.  I paired them together because their weights are virtually the same, so we'd expect them to have similar average uirine caffeine concentrations, but it's obviously not the case.  Subject 1's average urine caffeine concentration is only half that of subject two! D. J. Birkett and J. O. Miners concluded:

Despite this relatively modest intake, one of the subjects showed a urine caffeine concentration close to the international sporting limit of 12 mg l-1. Even with this small and relatively homogeneous group of subjects, the overall variability in urine caffeine concentrations was 15.9-fold with a standard caffeine intake. In a more diverse population, the variability is likely to be even greater. Some individuals could well exceed the current regulatory limit with a coffee intake of about three to six cups of coffee per day, particularly if a urine sample was collected around a time of peak plasma caffeine concentration.  [...] Based on the present study, and on other studies of caffeine pharmacokinetics, a population variability of the order of 20-fold should be assumed.
That was in 1991.  But the news hasn't gotten any better in the last 20 years.  As Louise Burke bluntly states in the introduction to her extensive 2008 review paper mentioned earlier:

In the new millennium, the landscape of caffeine in sport has changed markedly.  First, there is greater awareness of the frailty of urinary caffeine concentrations as a marker of caffeine use. Urinary concentration reflects the small amount (~1%) of plasma caffeine that escapes metabolism and is excreted unchanged.  Metabolic clearance of caffeine varies widely among athletes and among different occasions of use by the same athlete.  [...] Since there is huge variation in urinary caffeine content for the same caffeine dose, and neither the standardization of the time between caffeine intake and urine collection nor the prevention of opportunities to urinate during or after an event, we now recognize that urinary caffeine levels have no practical utility as markers of a particular use of caffeine. [emphasis added]
 The IOC and WADA removed caffeine from its banned substances list at the start of 2004.  The NCAA hasn't gotten the memo yet.  Here are two scenarios that illustrate the problems with the NCAA's current policy on caffeine:

Scenario 1

Samantha is a 5'2 105-pound (47 kg) freshman distance runner at a Division I university and a regular coffee drinker.  Like many women her age, Samantha has just started taking oral contraceptives.  After a late night studying, she wakes up early for a 9:20 am class and fills her 16 ounce Caribou Coffee mug with coffee at the cafeteria.  She drinks it all about halfway through her lecture, around 10am.  At 2pm, Samantha goes to cross country practice, where the NCAA is conducting mandatory in-season drug testing.  Her urine is tested.  Is she at risk of failing the test?

The coffee Samantha drank is of higher-than-average strength, with 175 mg of caffeine per 7 oz. cup, meaning that Samantha consumed 2.28 cups of coffee, or 399 mg of caffeine.  This works out to a dosage of  8.5 mg/kg–a lot for a normal person, but nothing unusual for a regular coffee drinker.  Since she finished her coffee at 10am, her blood plasma caffeine levels peaked at around 11am.  Three hours later at practice, her body has eliminated some caffeine, but not very much.  Her birth control pills  raise her caffeine elimination half-life to ten hours, meaning that after three hours, our model predicts that she still has 7.4 mg/kg in her system.  This would translate to a blood plasma concentration of 14.8 mg/L.  Recall that we used a blood plasma concentration to urine concentration ratio of 1.3–the blood should have 1.3 times more caffeine than the urine (11.4 mg/L).  But looking over the results from Birkett and Miners in the table above, we can see that this ratio (Cp/Cu, third column from right) can often be lower, and in some cases, below one.  This means the level of caffeine in her urine could be higher than in her blood (14.8 mg/L).  The NCAA limit is 15 mg/L.  Thus, it is very possible that Samantha could fail her urine test.

Scenario 2

Sam is a 5'9 140-pound (63 kg) senior distance runner for a Division II university.  He has qualified for the 10,000m at DII nationals with a provisionally-qualifying time of 30:00 at his conference meet.  His incoming time ranks him 16th in the field.  After running his qualifying time, he read a scientific review article about the ergogenic properties caffeine and would like to use it to boost his performance at nationals.  He decides on a dosage of about 5 mg/kg and purchases a bottle of 100mg caffeine tablets at his school's bookstore.  An hour before a workout, he takes three tablets to ensure he tolerates it well. He feels great in the workout, and decides to repeat the same protocol for the national championships.  One week later at Division II nationals, Sam takes three tablets an hour before his race, runs 29:24 (a 2% improvement) and places 3rd, garnering All-American status.  After the awards ceremony, Sam is asked to provide a urine sample.  Is Sam at risk of failing his drug test?


Sam weighs 63 kg and consumed 300 mg of caffeine, a dosage of 4.76 mg/kg.  According to our model, his blood caffeine levels peaked at the start of the race at 9.52 mg/L, which means his urine caffeine concentration was 7.32 mg/L.  But Sam is not actually tested until after the awards ceremony.  The race itself takes half an hour, and it takes another half an hour for Sam to be escorted to the drug testing area and provide his sample.  Sam has a regular caffeine metabolism with an elimination half-life of 4.9 hours. In the hour that has elapsed between his peak caffeine level and his urine sample, his effective dosage has dropped to 4.13 mg/kg, which translates to a predicted blood plasma concentration of 8.26 mg/L and a urine concentration of 6.35 mg/L.  Even if Sam's urine had twice our predicted concentration of caffeine (in Pasman's study, the subjects who took 5 mg/kg of caffeine had an average urine concentration of 4.8 ± 1.8 mg/L–a level of 12.7 would represent a data point nearly eight standard deviations above normal), he would STILL be below the NCAA limit of 15 mg/L.  There is virtually no chance Sam will fail his drug test.


Implications and Ethics

So we've found ourselves in a bit of a conundrum.  Samantha, who did not intend to boost her performance and ingested a natural substance she and millions of other Americans drink every day, could test positive for caffeine and suffer the consequences, and Sam, who intentionally took a tablet containing pure caffeine for the express purpose of boosting his performance, is nowhere near the testing standard.  Clearly, the NCAA needs to revise its policy on caffeine.  But as we've seen described in many, many peer-reviewed scientific articles, the amount of caffeine necessary to significantly boost performance in an endurance event is well within the normal amount consumed by millions of people every single day.  As mentioned earlier, 3 mg/kg of caffeine is enough to significantly boost performance, and higher doses do not show a stronger effect.  A 60 kg (132 lb) distance runner only needs 180 mg of caffeine to achieve this level.  That's only about eight ounces of coffee an hour before a race or workout.

So how do we sort through the ethics of ergogenic aids? The issue isn't black and white.  There are some things, like getting more sleep and drinking chocolate milk after a workout, that nobody would conceivably claim were cheating or doping, but definitely boost performance.  On the other hand, few people would deny that injecting erythropoietin (EPO) every night is dopingnot just because it's against the rules, but because it's artificial, it's not available to everyone, and it's dangerous.  But in the middle, there is a gray area--what about injecting vitamin B12? Or sleeping in an altitude tent? Or taking caffeine tablets before a race? 

According to the WADA Code, for a substance or method to be included on the prohibited list, it must meet two of the following three criteria:
*Medical or other scientific evidence, pharmacological effect or experience that the substance or method has the potential to enhance or enhances sport performance;
*Medical or other scientific evidence, pharmacological effect, or experience that the Use of the substance or method represents an actual or potential health risk to the Athlete
*WADA's determination that the Use of the substance or method violates the spirit of sport described in the introduction to the Code.

This isn't actually very useful, because it gives the WADA a very vague cop-out for anything it determines to be contrary to the spirit of the sport.  The "spirit of the sport" as defined in the introduction extolls similarly-vague values like fairness, fair play, and honesty.  It's easy to get lost in abstract nouns when dealing with things like "fairness" and "ethics," so let's bring it back down to earth.  What is it about injecting EPO or taking steroids that feels wrong, and why don't we feel that way about drinking chocolate milk after a workout or living at high altitude?

First off, it involves supplying the body with artifically-produced, synthetic compounds specifically designed to boost performance.  Second, there is something about injections, pills, and IVs that seems "unnatural" when compared to normal eating and drinking.  Indeed, the WADA prohibits intravenous fluids for any nonmedical purpose, even if they are not supplying a banned substance.

Rumors flew a few years ago about WADA banning altitude tents, but the ban never became reality for a few reasons.  First, there is relatively little risk in using an altitude tent.  One could conceivably cause harm by cranking the altitude setting up too high, but this would not be beneficial to performance anyhow.  Second, there is no significant difference in an altitude tent and a real location at high altitude–the tent isn't providing a big difference between the effect that can be achieved at popular live-high-train-low locations like Flagstaff, Arizona.  Finally, a ban on altitude tents would be unenforceable.  Without midnight raids on athletes' residences, detecting their use would be impossible.  Sadly, it is also currently impossible to detect use of many clear-cut-wrong doping methods.  For example, there is no urine test today that can detect the use of human growth hormone (hGH), one of the most powerful doping agents for endurance sports, and a test for EPO (the other "big gun" in endurance cheating) wasn't developed until 2003. 

So, returning to caffeine: Is it cheating? Cheating is, by definition, breaking the rules. Currently, WADA says using caffeine is not against the rules–you can down No Doz to your heart's content without failing a drug test.  According to the NCAA, you are cheating only if your urine has a caffeine concentration higher than 15 mg/L. 


Is it wrong? The thing that might bother you about Sam, the Division II runner who took caffeine tablets before his race, is that taking pills seems "unnatural"–the caffeine had to be extracted, concentrated, and pressed into a pill.  But I argue that Samantha did nearly the same thing, chemically speaking.  Coffee is an artificially-extracted compound from a natural source.  In fact, the only difference between where coffee comes from and where pure caffeine comes from is the solvent used to do the extraction.  Coffee is made by passing hot water through ground and roasted seeds from plants of the coffea genus.  A nearly identical process can be used to extract caffeine.  Simply swap out the hot water for benzene, dichloromethane, or supercritical carbon dioxide and you'll have a cupful of caffeine instead of coffee.  Evaporate the solvent and you've got anhydrous caffeine powder (evaporate the solvent from coffee and you've got instant coffee mix).  Moreover, caffeine in drinks like Coco-Cola or Mountain Dew is artificially added back into the drink, which, going by the natural/unnatural logic, is even worse than the caffeine pills!  Finally, unlike the difference between endogenous testosterone (made by your own body) and synthetic testosterone, there's no chemical difference between caffeine from a natural source and caffeine from an unnatural one.  So if there is a difference between what Sam did and what Samantha did, it lies only in why they consumed caffeine.  While this might be solid grounding for a moral or ethical argument, it is no basis for a regulatory one.  Rules based solely on why an athlete takes a substance are flat-out silly:  "No sir, honestly, I just take steroids because they help me lift all my heavy textbooks for class!"


So, just like altitude tents, there is no good rational to ban caffeine use at any level in sport.  It is most beneficial at very safe dosages, so using it for its ergogenic properties causes no risk to an athlete's health.  It's a completely natural substance consumed on a daily basis by over 90% of the population.  And finally, testing for caffeine abuse is difficult, unreliable, and ineffective–a single cup of coffee is enough to significantly boost performance for the average distance runner, and this level of caffeine can easily result from normal, social consumption of caffeinated food and drink.  Given the scientific facts, the NCAA is faced with banning caffeine completely or removing it from the prohibited substances list. While the first option wouldn't bother runners at Brigham Young, nearly every other college athlete would be outraged at a season-long prohibition on coffee, tea, cola, and especially chocolate.  Indeed, WADA dropped caffeine from its list in 2004 for precisely these reasons.  The NCAA should quickly follow suit.


Recommendations and Conclusions

Whether to use caffeine to boost your performance is up to you.  I've shown that drug testing for caffeine sits on unsound scientific ground, and thus it makes no sense to test or punish any athlete for using it.  But whether it is right to use caffeine to boost your performance is less clear-cut, and what you believe is right may not always be what is in the rulebook.  Some people will undoubtedly think using caffeine is "just plain wrong."  But many people also think that refusing to lead a race or sitting on a teammate is "just plain wrong," and neither of those are against the rules.  To other people (including me), using caffeine is a completely normal part of everyday life, so using it to boost race performance is no more morally objectionable than getting more sleep or carbo-loading.  For college runners, there is an additional dimension to the moral dilemma: do you follow the letter of the rules, or the spirit behind them? Drug Free Sport, the NCAA's anti-drug marketing campaign, says rather bluntly, "The NCAA bans caffeine because it is found to be a performance enhancer."  So the NCAA probably intends competition to be between uncaffeinated competitors.  But you are not breaking the rules unless your urine level is above 15 mg/L, and as we've seen, it is quite easy to achieve an ergogenic dosage while keeping your urine levels far below the limit. 

So, are you the same runner if you take caffeine before a race to boost your performance? Are you the same runner if you get more sleep the night before a race? Are you the same runner if you inject EPO or hGH every night? Is that you out there, setting a new PR? Right now, WADA says "yes, yes, and no," respectively; the NCAA says "no, yes, and no." Ultimately, it will be up to you to decide on this issue, just like it's up to you to decide whether to lead a race or sit on a teammate or sleep in an altitude tent or drink chocolate milk after you work out.

But, to wrap things up, if you do decide to use caffeine to run faster in your next race, I can summarize the practical aspects of this post with a few recommendations:
  •  Use a low to moderate dose.  There's no evidence that exceeding doses of 3-5 mg/kg offers any advantages.  In all likelihood, you will not see an additional boost to performance, but may feel some of the negative side effects of higher dosages.  NCAA athletes competing in races which may involve post-race drug testing (i.e. the national championships) especially have an incentive to stick to 3-4 mg/kg.
  • Decide on a caffeine source. Whether you drink coffee, tea, or take caffeine pills, figure out how you want to get your caffeine and get used to it.  Remember, this is something you'll have to consume in a short period of time about an hour before a race, so six cups of tea or five chocolate bars is not a good idea.  Caffeine pills will allow you to precisely control your dosage, while coffee or espresso might feel like more natural options.
  • Avoid energy drinks and energy supplements–drinks like Rockstar, Red Bull, and 5-Hour Energy are loaded with megadoses of unproven supplements, vitamins, and minerals, none of which you need and some of which (like synephrine) may actually be on the NCAA or WADA banned substances list.  There is a whole world of unknown in the field of energy drinks and energy supplements, and you would do well to have nothing to do with it.
  • Try it out before. Just like any new addition to your race-day routine, consuming caffeine should be tested out in a workout.  It's better to find out that you don't tolerate a double-shot of espresso 10 minutes before your warm-up in a workout than in a race! 
  • Abstain from caffeine for 24-48 hours before.  Scientists have postulated that having a caffeine tolerance may blunt its ergogenic boost, but the evidence on this is unclear.  It certainly doesn't hurt to abstain from caffeine for a day or two beforehand--this is the standard protocol in most studies.
 In conclusion, there is a huge body of scientific evidence that low to moderate doses of caffeine, taken 60-90 minutes before an athletic effort, offer a significant advantage to the endurance athlete.  Additionally, there is ample scientific evidence that testing urine for caffeine is unreliable; levels of caffeine in urine do not accurately predict the amount of caffeine ingested by an athlete.  The NCAA rules currently in place offer no serious barrier to the athlete seeking to boost his or her performance with caffeine, while threatening a few unlucky athletes who are simply social coffee drinkers not even intending to boost their performance.  As a chemist and a runner, I believe the NCAA's current policy on caffeine is untenable and I recommend they remove it from the banned substances list immediately.  

    2 comments:

    1. My biggest problem with the caffeine research is that they usually use habitual caffeine users and then deprive them of caffeine for a couple days. It is hard to separate what is a performance enhancement and what is really just resolving withdrawal symptoms. Also, in big events such as nationals the CNS is usually already sufficiently stimulated compared to a laboratory test with very little incentive for maximized performance. Haha, if you can't tell I'm not a huge caffeine proponent. Though I think your right if you are going to consume caffeine for performance enhancement it is best to use it only prior to big workouts and races and not habitually. If you are tired, sleep.

      ReplyDelete
    2. Great article! I use 100-200mg of caffeine before races and feel GREAT.

      ReplyDelete