Viagra and Baseball Player Performance

Over the past few weeks a few articles have mentioned that many athletes have begun using Viagara to help with their endurance. Although Viagra has become as well known as the Pill, it is probably about as well understood in the mainstream. Players claim that this drug helps transport oxygen, nutrients, and other performance enhancing drugs to muscle. There is some biological basis for this to work, but much of it is part of the pseudoscience that permeates many a gym. Gym science has a tendency to be 1 part science, 1 part wishful thinking, and quite often a dash to scam to give it some flavor.






To understand Viagra, you need to understand erectile dysfunction. To start simply, erectile dysfunction is when a male is unable to develop or sustain an erection. This failure to launch is very much a bio-engineer process. At first thought, you might think that the penis is like any of your other appendages. By that, I mean, when you move your arm, you do so by employing muscle contractions. Erections do not work this way. An erection is the result of a hydraulic process that controls blood flow in the penis and, specifically, the corpora cavernosa.

How Does an Erection Work
When the penis is flaccid, arterial blood flow is constricted preventing the corpora cavernosa from becoming engorged with blood. An erection occurs when the a neurological signal activates a non-androgenic, non-chlorinergic nerve cell ending. This particular nerve cell is able to release nitric oxide into the blood. This chemical stimulates guanylate cyclase, which in turns upregulates cyclic guanosine monophosphate (cGMP). Now, cGMP targets smooth muscle, which is what arteries are made of. This chemical causes the arteries to vasodilate, causing an increase in blood flow. Having a permanent erection is not ideal, so the body is designed to eventually degrade cGMP and cause vasoconstriction. This is accomplished by the enzyme phosphodiesterase (PDE).

How does Viagra Work
Erectile dysfunction is often caused by too low a concentration of cGMP. This biological process has three easily identifiable parts for us to manipulate:
1) Increase nitric oxide;
2) Accelerate cGMP production in response to nitric oxide presense; or
3) Inhibit PDE activity in order to allow cGMP to reach a high enough concentration to sustain an erection.
Viagra's function utilizes the third part of this process. It targets PDE.

PDE is an enzyme. An enzyme is essentially a protein that assumes a specific shape. The shape is able to latch onto cGMP and then metabolize it to a form that no longer dilates smooth muscle. The key to prevent cGMP metabolism is to inhibit or inactivate PDE. Viagra is the trade name for sildenafil citrate. Sildenafil is able to latch onto PDE, but it does not get metabolized and PDE does not readily release the compound. This limits the amount of free PDE to act upon cGMP. Eventually, the free compound is processed by other metabolic processes in the liver and is depurated from the body.

PDE Isozyme (Different Shapes for Different Function)
Now what makes this mechanism work to fix erectile dysfunction is that the corpora cavernosa contains PDE isozyme 5. PDEs have several shapes and each are rather specific to a certain function. This is quite important physiologically and pharmacologically. For instance, biologically it is important that erectile function (PDE 5) is not regulated concurrently with heart contractility (PDE 3). Otherwise, reproduction would have a high rate of lethality. Likewise, for pharmacological use, it allows us to focus on inactivating or inhibiting a specific PDE isozyme. Viagra has a 10,000 times greater affinity to binding with PDE 5 than PDE 3. This is actually why Viagra was originally a failed drug. It was developed to help with hypertension, but the compound had little effect on PDE 3. By accident, they found it worked on erectile dysfunction.




Problem With PDE 5 as a Baseball Performance Enhancer
The specificity of Viagra makes it initially out to be an unlikely PED. Studies have shown that this compound can help with pulmonary vasodilation in newborns and patients with severe heart conditions. Furthermore, in 2006 Hsu et al. found that Viagra could improve athletic performance by 40% at 10,000 ft. No dose dependant relationship was observed. Nor was this effect observable at lower altitudes. Experiments at lower elevations were followed up using Cialis (another PDE 5 inhibitor, but certainly different) by Di Luigi et al (2008) and found that under these conditions there were no observable effects. It appears that Viagra's vasodilatory effect works, but only in cases of severe hypoxia. Arguably, baseball players may experience this at Coor's field (5200 ft). I doubt it. If anyone has hiked at 10k, you can tell it is far different from hiking at 5k. With baseball being a game of short-lived moments of exertion, I doubt that the body will ever come under hypoxic conditions. Although I doubt it would work, maybe it would be more useful for cyclists, track and field, basketball players, or football players. Guys who you actually see physically drained after games. Of course, this comes with the caveat of high altitude hypoxia where oxygen diffusion rates are significantly depressed.

At sea level, I just wonder what the effect will be. Upping the concentration may have some serious pulmonary and vision effects would actually decrease performance while offering nothing beneficial to the user. I think the reason why high altitude performance, infants, and patients with poor arteries may benefit from Viagra is because this population actually suffers from reduced blood access from vasoconstriction. A healthy person at sea level just will not have a situation where his blood flow is limiting oxygen transfer to the skeletal muscle. The diffusion rate is not the issue. It is the consumption rate of the muscle.

Conclusion
As I have mentioned before, athletes are a desperate and superstitious bunch. In fact, we all are. We tend to look for any and every advantage in difficult and trying circumstances. I think trying to stay in the majors and earn millions of dollars is a pretty stressful life. You all may laugh at the concept of a ball player having a tough life, but it is true. He has a short career length and each year is basically equivalent to 10% of his lifetime earnings. In response to that, ball players do weird things. Cap Anson never spoke to his starting pitcher on the day of the start. In the 1890s, the Baltimore Orioles were known to do shots of Turkey gravy an hour before game time in the midst of one of their memorable runs. Wade Boggs ate fried chicken and always had a can of beer in his hand. Guys don't step on the foul line between innings. Players wear the same unwashed clothes during a streak. Giambi and the Yanks share a gold thong when one of them gets into a slump.

Unlike those, the use of Viagra is based in some scientific fact. It is a vasodilator . . . though an incredibly specific vasodilator. It reminds me of Ivan Rodriguez and countless other ball players. They piss on their hands to prevent blistering. This actually makes scientific sense, but it is misapplied. Check your hand moisterizer and you'll find uryl sulfonate or some version of that. That is basically urea. Piss. The lack of understanding exhibited by ball players, but not by chemists, is that urea has to be on your hands for several minutes for it to keep your hands soft. So, if you want to be cheap about it . . . soak your hands in a bucket of urine for 20 minutes and you'll beat the system. hGH is another PED that is similarly rooted in science, but is misapplied. Players took hGH thinking it would help them develop muscle when all it did for them was cause acromegaly. The list goes on and on and on. The key is to remain skeptical when any drug emerges from the gym. Most often, it does not do much of anything but be a drain on your wallet and your liver.