Is cannabis a performance
enhancing substance?
Michael Phelps was caught on camera smoking marijuana in 2009 (nytimes):
As a result of Michael Phelps's unfortunately public transgression he lost a lucrative
contract with Kellogg and USA Swimming banned him from competition for 3 months
(nytimes). The United States Anti Doping Agency (USADA) did not move to ban
Phelps from competition or punish him in any manner.
Penalties for marijuana as issued by USADA range from 3
months – 1 year dependent upon the severity of the infraction. (usatoday)
USADA policy regarding marijuana are as follows:
“Currently USADA will only consider TUE applications for
legal, FDA-approved uses of THC, such as Dronabinol to manage some of the
symptoms of AIDS, or to treat nausea and vomiting caused by cancer
chemotherapy.” -USADA
Penalties for performance enhancing substances such as blood
doping agent erythropoietin (EPO) are lengthy to permanent bans from
competition with associated fines. EPO is an agent that signals for the
increased production of erythrocytes, increasing the oxygen carrying capacity
of an athlete’s blood. The
reasoning behind the banning of a pharmacological agent that alter the
architecture of the blood is self-evident.
Lance Armstrong was stripped of his seven Tour de France
titles and issued a lifetime ban from the sport of cycling for knowingly blood
doping using EPO (nytimes).
If an agent existed that could pharmacologically enhance
pulmonary function would USADA treat it as a performance enhancing substance? One could imagine that if an athlete had the ability to
enhance their pulmonary function they would gain an unfair advantage.
Recent research into the pulmonary function has described
just such a substance. Spirometry measurements taken from 5115 adults found
that vital capacity and forced expiratory volume in 1 second (FEV1) were higher
for marijuana smokers than controls (Pletcher). FEV1, which is a measure of the
speed at which one can expel air thus measuring resistance through the airway, was elevated in marijuana smokers as
compared to controls until individuals were undertaking more than 23 uses/month
or had exceeded 32 joint years of lifetime use. The greatest positive effect
marijuana consumption had on FEV-1 was a 60ml enhancement at 10 joint years and
a 40ml increase at 18 uses/month.
Consider
that! The maximum enhancement of marijuana use of FEV1 was found in those using
18 times/month. The people who were smoking more days than not had the best FEV1s.
Even more compelling evidence to marijuana’s pulmonary
enhancing qualities is the dose dependent effect on vital capacity. Vital
capacity was found to be positively correlated to increased exposure in a
linear fashion.
There
was no dosage found at which consumption reflected a decline in vital capacity.
The more people consumed the higher their vital capacity.
This study and many others quantified the dose dependent,
precipitous, and linear decline in vital capacity and FEV-1 of tobacco smokers.
The smoking of marijuana clearly has very different effects on pulmonary function than
tobacco.
Pletcher et al. presents concrete evidence for marijuana’s
sustained performance enhancing effects. USADA would be well advised to reassess its stance on the use of marijuana. Cyclists, Olympic runners, and
swimmers could potentially use marijuana with the intention of enhancing their
pulmonary function.
If an athlete were intending to use marijuana for the
purpose of pulmonary enhancement they would be heartened to learn that not only
have the long term pulmonary enhancements of cannabis consumption been
elucidated by Pletcher et al., the transient, short-term effects of smoking
marijuana have been quantified as well (Tertault et al.). Eleven out of twelve
studies found short-term bronchodilation as measured by transient
increases in FEV1 (Tertault et al.). These increases were found to be anywhere
from 150ml-250ml (Tertault et al.). These values represent roughly a 5% enhancement of FEV1.
These short-term transient effects could provide athletes
with an unfair advantage during training. If an athlete were to consume
marijuana immediately prior to an aerobic threshold workout they may be able to
go harder, and faster during that workout due to significant bronchodilation and increased oxygen delivery.
If an athlete were to regularly smoke marijuana prior to strenuous aerobic training
they may be able to train at an intensity that would otherwise unattainable for
them. Consistent, abnormally intense aerobic training has the potential to provide
athletes with an unfair pharmacologically induced advantage. USADA needs to evaluate
the research that is available on cannabis consumption and pulmonary function
in order to bring their marijuana policy in line with the regulations they have
surrounding other performance enhancing substances.
Pletcher MJ, Vittinghoff E, Kalhan R, Richman J, Safford M, Sidney
S, Lin F, Kertesz S. Association Between Marijuana Exposure and
Pulmonary Function over 20 years The Coronary Artery Risk Development in Young
Adults (CARDIA) Study. Journal of the American Medical Association 307(2): 173-181, Jan 2012
Tashkin DP. Effects of marijuana smoking
on the lung. Annals of the American Thoracic Society 10(3): 239-247, Jun 2013
Tetrault JM, Crothers K, Moore BA, Mehra R, Concato J, Fiellin DA. Effects of marijuana smoking on pulmonary function and
respiratory complications: a systematic review. Archives of Internal
Medicine 167(3): 221-228, Feb 2007
This is a rather fascinating blog post, Austin. The concept of marijuana enhancing overall athletic ability appears to oppose my initial perception of the athletic effects of smoking marijuana. It's hard not to think of all smokers having a horrible cough, damaged cilia in the psuedostratified epithelium of the respiratory track, and a diminished tidal volume. The error, of course, in my thinking was that smoking tobacco and marijuana led to the same negative respiratory outcome. Chemically speaking, these are two different substances containing dissimilar compounds. My next question would be do you personally think the USADA should deem marijuana a performance enhancing substance? The 5% overall enhancement of FEV1 seems low in comparison to other performance enhancing drugs like anabolic steroids, EPO, stimulants, etc. Regardless, I suppose even a small edge over an opponent should be deemed an unfair advantage. There definitely needs to be more research done on this particular topic as well as a solid evaluation of ethics. Additionally, I found another journal article in The New England Journal of Medicine that supports your findings as well (http://www.nejm.org/doi/full/10.1056/NEJM197308162890702). You can only see the abstract, but it gives the results of the overall study which is pretty interesting.
ReplyDeleteIn response to Lorraina: Based on the evidence presented in Austin's post as well as the article you linked I think marijuana could be classified as a performance enhancing substance based upon the increases in vital capacity and FEV1. Increasing these values could give athletes a significant advantage over their competitors. However I think they should be hesitant to release a statement deeming marijuana a performance enhancing drug until more research on this topic has been conducted. Deeming marijuana a PED could also have some negative societal impacts if the USADA takes that position because it could lead to increased consumption especially in younger populations.
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