Marijuana aids athletes’ performance? Science says no

When Sha’Carri Richardson was barred from the Olympics this month after testing positive for marijuana, it ignited an ongoing conversation about whether the drug should be classified as performance-enhancing for athletes. Does getting high really improve strength, speed, agility or other outcomes?

In Richardson’s case, the answer doesn’t matter, because marijuana is also prohibited, as enforcement organisations assert that it can harm athletes and that its use violates the spirit of the games. Her ban stands whether or not the drug is performance-enhancing.

Marijuana was added to the list of banned substances after a Canadian gold medalist had tested positive for the drug in 1998. Shortly after, the US Office of National Drug Control Policy put out a paper explaining that the medal “seemed to directly undercut our messages to young people that drug use undermines a child’s opportunities for success.”

Still, the question of the drug’s influence on athletic ability also plays a part in its placement on the list, and the World Anti-Doping Agency has said that one of the three reasons it has banned cannabis is because the drug can enhance performance. As signatories to the WADA code, the US Anti-Doping Agency and the US Olympic & Paralympic Committee follow its rules.

Also read: Why marijuana can disqualify a runner from the Olympics

But the idea that marijuana improves performance is not supported by science. To the contrary, the evidence is inconclusive at best, while an overview of the research concludes that marijuana hinders performance by reducing stamina and peak performance while increasing heart and breathing rates.

A close examination of the scientific literature reveals an additional wrinkle: In justifying its ban on the drug, WADA, which sets the policy for drug prohibition, has overstated anecdotal and speculative evidence, experts said.

In 2011, two WADA scientists and an adviser wrote a paper that is widely cited as representing WADA’s argument that marijuana should be prohibited because it can enhance performance. But some experts question the paper’s accuracy.

“The ‘evidence’ is extraordinarily weak, at least as far as this paper goes,” said Margaret Haney, a professor of neurobiology at Columbia University, where she is director of the Cannabis Research Laboratory. Haney said that the broader body of research — going beyond the crucial 2011 paper — also didn’t support the claims. Marijuana, she said, “reduces reaction time and has other effects that would worsen performance.”

In 2020, two independent papers looked at existing research into the question of whether the drug improves performance. The studies reached related conclusions: that the evidence does not support that idea.

One study concluded that the drug “does not act as a sport performance enhancing agent as raised by popular beliefs.”

It added, “Thus, cannabis consumption prior to exercise should be avoided in order to maximise performance in sports.”

A spokesperson for WADA, Jon Fitzgerald, said that WADA “consults with all stakeholders in relation to substances or methods that perhaps should be added or removed,” and he added that “throughout this time, the US has been consistent in its strongly held position that WADA should keep cannabis on the List.”

Fitzgerald said that the WADA authors “stand by” the 2011 scientific analysis, published in the journal Sports Medicine, that looks expansively at the effects of marijuana use on athletes. One section is devoted to the drug’s potential to enhance performance and draws on a handful of previous scientific studies to support that possibility.

Experts say the WADA analysis goes beyond what the earlier papers actually stated.

In one example, the 2011 analysis misstates the position expressed by a scientist named Jon Wagner in his 1989 paper titled “Abuse of Drugs Used to Enhance Athletic Performance.” The WADA paper asserts that Wagner “described cannabis as ergogenic,” meaning performance-enhancing. Wagner, a former assistant professor at the University of Nebraska who now works in the biotech industry, disagreed.

“I didn’t write that,” Wagner said in an interview. In the paper, he wrote that marijuana doesn’t improve “vital capacity” or grip strength and that if marijuana helped at all, it would be by helping an athlete relax. In an interview, he said he had taken that last idea from anecdotal conversations with tennis players.

“That’s just it,” Wagner said. “People just talking.

“That was like a throwaway line,” he added. “I didn’t imagine it would have an impact in the world of Olympics.”

Fitzgerald countered that Wagner’s anecdotal evidence fit the meaning of “ergogenic.”

The WADA study also cites the authors of a 1996 paper, titled “Performance-Enhancing Drugs, Fair Competition, and Olympic Sport,” as making the claim that “cannabis could be performance enhancing in sports that require greater concentration.”

In fact, the authors of the earlier paper took no position on whether marijuana is performance-enhancing and offered no scientific evidence that would support that position. Rather, they wrote that one argument holds that marijuana decreases performance, while “some argue that it might enhance performance in sports that require great concentration.”

Fitzgerald said that the WADA scientists had “exactly” quoted from the 1996 paper.

In another example, the 2011 WADA paper cites a study of 12 cyclists who performed more poorly after using cannabinoids. But the 2011 authors note that the cyclist study also offered evidence that marijuana could be performance-enhancing by “suggesting that cannabis could also improve oxygenation to the tissue.”

Haney, from Columbia, said that such a piece of evidence didn’t make it clear that marijuana was performance-enhancing.

“That’s just supposition,” she said. She added that the study of cyclists had illustrated a larger point: “It worsened performance!”

Roger Pielke Jr., an expert in sports governance and a professor of environmental studies at the University of Colorado Boulder, said that he had looked at the 2011 paper and had found it problematic and an example of “anti-doping theatre.”

He also called it “policy-based science,” in which the decision to prohibit a drug is made before the science is clearly established.

Also critical of the WADA position is Jeff Novitzky, senior vice president of athlete health and performance for the Ultimate Fighting Championship, which falls under the governance of WADA and USADA.

Novitzky said he had heard UFC and mixed martial arts competitors joke that they would be happy if a competitor were stoned because it would slow reaction time and give an advantage to an opponent. Novitzky said that the problem with WADA’s poor scientific justification was that it could jeopardise athletes’ careers.

“If you’re taking away the ability for a human being to earn a living, you better be 1,000% sure,” he said.

He added that WADA’s decision to focus on performance enhancement was not trivial because it is one of only three criteria involved in banning a drug.

A principal line of thinking stemming from the 2011 paper and other literature is speculation that the performance-enhancing capacities of cannabis come from the drug’s capacity to relax people. Experts said it was undoubtedly true that marijuana could relax some people, but with a side effect of hindering performance.

One challenge in reaching conclusions about the impact of marijuana on performance or health is that, historically, the drug has not been subject to rigorous study. That is partly because it is considered a Schedule 1 drug by the US government, linking it with dangerous, frequently abused drugs and limiting its availability for research.

Still, Novitzky, from the UFC, said he had spoken with many athletes who used marijuana for pain management, sleep and relaxation. But he said the athletes had told him that they regularly stopped using it weeks before a fight.

Novitzky argued that the question should not be whether an athlete had tested positive for marijuana — because the drug can stay in the system for weeks — but whether an athlete was impaired and risked being hurt.

Haney said that “people certainly use alcohol to decrease anxiety” and that if WADA considers cannabis performance-enhancing because it decreases anxiety, that would also be “inconsistent with alcohol.”