Heads Up: You're looking at roughly 1500 words on the topic of caffeine. Enjoy.
Whether it's right or wrong, justified or not...caffeine is the only drug I can think of that gets a free pass in our society. The majority of Americans consume caffeine; more than 80% consume the drug regularly. Yet, most don't even really view it as a drug, despite the fact that it is a stimulant and a potent, effective one at that. It isn't respected as much as it should be and its usefulness, as well as its possible adverse effects are further confounded by the polarity in which it is presented by either zealous proponents or stark critics. Despite the plethora of research, information and misinformation out there, the majority share a silent agreement in their love for this substance; athletes not excluded. The goal of this piece is to uncover some basics of caffeine, take a deeper look at its possible usage in athletics and offer personal account.
Numerous athletes have touted caffeine as a means of improving physical strength, power output and endurance performance. But, what does caffeine do and how does it do it? First of all, I'm not a neuroscientist, I'm not a doctor and I'm not a master of pharmacology; however, my reading has, at the very least, conferred a basic understanding of caffeine mechanics. Let's take a very basic look at your brain and nervous system. The neurons in your brain are constantly active and a byproduct of neuron activity is adenosine. Adenosine is a naturally occurring nucleoside (a nitrogenous base attached to a 5-carbon sugar, typically ribose) which serves as an inhibitory neurotransmitter. As an inhibitory neurotransmitter, adenosine acts as a CNS depressant and confers sleepiness and reduces overall arousal. Typically, the harder your neurons fire, the more adenosine is created as a byproduct, which is at least part of the reason for fatigue. Adenosine receptors serve to monitor these levels in your brain and body; as levels rise, so does your bodies feelings of sleepiness and fatigue...telling you to cool it. Caffeine has the unique ability to fit comfortably in your adenosine receptors (particularly A1 receptors). The key here is that caffeine does not activate those receptors like adenosine does and therefore, blocks the activity of adenosine at the receptor site. This allows for dopamine and glutamate to do their work as natural CNS stimulants. So, it isn't that caffeine is directly stimulating, like amphetamines or other stimulants, rather it allows for your brain to stay stimulated depending upon the levels of your own excitatory neurotransmitters at the given time. Also worth mentioning, there is some research to indicate that caffeine can amplify the effect of dopamine, but the majority of effect is due to adenosine receptor antagonism. Just based upon this fact, caffeine is limited as to how "wired" you feel from its presence. You cannot dose caffeine higher and higher and expect to feel more and more energized, unfortunately it does not work that way.
The above effects are also influenced by individual differences between people; genetic factors and individual tolerance to name a couple. Tolerance is a big one here. I don't believe it is fully understood as to how and why we become increasingly tolerant to caffeine, but we can agree that it does happen. Habitual use does indeed diminish much of the "first time" effects, such as euphoria etc; once tolerance reaches a certain level, usage will only confer the benefit of reducing feelings of sleepiness. An unfortunate, however unique property of caffeine is that this tolerance is considered "insurmountable". That is, taking in increasingly higher levels of the substance will not confer those previously felt effects, no matter how high you decide to dose. Which leads me to an important point that most (including myself) often times fail to heed: caffeine is best used sparingly if your desire is to feel those near magical effects like increased fat burning, increased strength and power output and of course, euphoria.
Now that we have gone over some of the basic mechanisms of how caffeine works (and stops working), we can now get into its application in performance enhancement. First of all, caffeine can confer the previously discussed benefits in a relatively virgin or infrequent user at doses as low as 70-100mg. However, the typical starter dosage for increasing lipolysis and/or deriving some athletic benefit tends to be right around 200mg. Some research indicates that those looking for significant increases in strength output may need to dose even higher, towards the 400-500mg range. Now, there are some implications with regards to size of the individual, body weight and just basic genetic predisposition, but those are general starting points. It is worth mentioning that much of the research utilizes dosage protocols around 4-6mg per kilogram of body weight. Again, it must be stated that this is basically a moot point if the individual is already very accustomed and tolerant to caffeine through regular or daily usage. Therefore, the above dosage recommendations best work in a situation where the dose is used sparingly, perhaps once per week. I'm not alone on this recommendation of decreasing the frequency of usage, as there are numerous well-educated experts in the field, such as Sol Orwell of Examine.com, who has stated that performance benefit is largely impacted by individual tolerance. So, we are only doing a disservice to ourselves by downing caffeine before each and every training session by way of pre-workout powders, coffee or caffeine pills; particularly, if the goal is acute performance enhancement.
Now that dosage and frequency has been discussed, let's tackle the applications of caffeine in specific athletic instances. We will begin with power output, since the majority of readers are mainly interested in weight training. Caffeine does increase strength acutely and this is backed by research, as well as the multitude of anecdotal accounts. Personally, I simply feel stronger and can push heavier weights with more ease under the influence of a good dose of caffeine before training. Although some research has shown to be inconclusive with regards to increases in 1 rep max strength. Wingate testing has shown definitive increases in power output of muscle cells which may imply otherwise. The research is pretty conclusive with regards to more sub-maximal loads, such as those around the 60% of 1 rep maximum range. At this level of load intensity, research has indicated approximately 10% increase in workload. It should be stated that the dosage used was around 6mg of caffeine per kilogram of body weight. Looking at the above, the strength athlete can definitely benefit from utilizing caffeine at the prescribed dosage before training. I believe this would apply to all disciplines as well; this would include bodybuilding, powerlifting and olympic weightlifting. The reasons for these performance benefits could be explained by a possible reduced perception of pain or exertion and/or more efficient mobilization of calcium within the muscle cells themselves.
Caffeine can be useful for increasing performance in endurance sports as well. With regards to anaerobic endurance sports, such as sprinting, improvements in exercise performance are notable. Research has shown improvements in sprint times when athletes consumed roughly 6mg of caffeine per kilogram of body weight. One study has shown a reduction in sprint time by 1.4%, which is significant. On the subject of aerobic endurance, caffeine seems to work very well at improving performance. The time to exhaustion for athletes utilizing caffeine at doses as low as 3mg per kilogram of body weight, has been shown to confer an almost 1.5 fold increase. Interestingly, this increased improvement in time to exhaustion was only seen in those naive to caffeine usage; these effects were not seen in those that identified as regular consumers of caffeine. For those of you who are "Why?" people and would like to know exactly how caffeine exhibits these performance benefits in endurance activity...there really is no definitive answer as to why and how, but there are theories. Some have presented the theory that caffeine works to improve aerobic endurance by increasing fatty acid usage and therefore, reducing the rate by which glycogen is depleted. Basically, caffeine could allow for the individual to use his/her own body fat stores more efficiently and not need to tap into glycogen to use glucose for fuel. However, this is far from conclusive, as it just hasn't been proven through the literature. Another theory presented is that caffeine effectively increases adrenaline release, which would confer endurance benefits. Again, this is not conclusive either, as the literature has not been able to definitively prove such. Perhaps the increases in performance could be explained by the previously stated reduction in perceived effort; perhaps it is by way of another mechanism that we have yet to uncover. Despite the why and how...one thing is for sure: it works.
This wouldn't be complete without touching upon the topic of safety. Assuming the individual is free of preexisting medical conditions, particularly related to the cardiovascular system, one would need to consume a rather large dose of caffeine to experience toxic effects. According to the literature, a dose of 20-40mg per kilogram of body weight would be considered toxic. There are actually some documented and researched health improvements indicated with consistent caffeine consumption and regular coffee drinkers. This is an entirely different beast, which won't be tackled in the confines of this article; just know that there may be actual benefits to regular, moderate consumption, which you may care to look into on your own time.
And that just about covers the basics of caffeine and its use in improving athletic performance. One point that I feel is of prime importance, is the notion of utilizing caffeine sparingly and within the effective dosage range. As much as we would all like to be caffeinated every day and enjoy all the benefits that caffeine has to offer, it simply does not play out that way in real world application. The negative implications of tolerance on the desired performance and cognitive benefits should not be ignored.
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