Michael Phelps avoided arrest in connection with his use of a marijuana pipe at a party in South Carolina last fall. But he has not dodged questions about why, as the world's most accomplished swimmer, he would consider taking the drug in the first place.
Reasons aside, he joins a long list of athletes who have been tied to marijuana, including Miami Dolphins running back Ricky Williams, Dallas Mavericks forward Josh Howard and Washington Nationals outfielder Elijah Dukes, all of whom have acknowledged taking the drug on the side. It begs the question: Does occasional use of marijuana affect athletic performance?
Numerous medical studies have shown that marijuana can impact a person's hand-eye coordination and the ability to concentrate and maintain attention. And a 2007 study from the Yale School of Medicine showed that long-term marijuana users can suffer the same debilitating lung problems as those who smoke cigarettes over a long period of time.
But it's less clear what that means for a young athlete who smokes marijuana occasionally during breaks in training. While doctors and trainers contend the short-term effects can be problematic, they acknowledge that some marijuana users claim the drug helps them deal with anxiety, stress and depression.
“It's still a very popular, recreational, 'let your hair down' way to party for athletes,” said Dave Ellis, a nutrition and conditioning consultant for college athletic programs and professional teams. “It's probably as popular as ever. I have to laugh because I think there's a lot of it going on.”
But knowing whether these athletes are hurting their abilities is tough to know, trainers and doctors said, because there has never been a scientific study on marijuana use and athletic performance. Finding subjects for such a study is challenging because researchers can't ethically ask people to take an illegal drug, and it's also hard to pinpoint the effects of marijuana if someone also drinks or smokes cigarettes occasionally.
Nevertheless, athletic trainers said they would like to see more information on how marijuana affects lung performance, if for no other reason to back up their own belief that it can be harmful.
“I think the thing that needs to be studied are the effects of taking that hot, 400-degree smoke and putting it in your respiratory system,” said Shawn Vass, a speed and agility trainer who operates Xtreme Acceleration Sports Performance, a specialized gym in Bethesda that caters to top athletes. “When it comes to a high-performance athlete, you want to make sure your breathing element, your filter, is as clean and as powerful as possible.”
Some studies have offered insight into how the drug is perceived compared to legal substances like tobacco and alcohol. Dr. Harrison Pope, director of the Biological Psychiatry Laboratory at Harvard's McLean Hospital, said his study of bodybuilders and weightlifters showed that marijuana use was widespread even among those who refused to smoke or drink out of fear of potential effects on their training.
“From my experience, these people scrupulously abstain from alcohol and scrupulously abstain from tobacco because they know it will interfere with their weightlifting or overall athletic performance,” Pope said. “The impression I get was that they fell back on marijuana because it was an intoxicant that they could use without having as much of an effect on their performance as the two legal intoxicants, alcohol or tobacco.”
But the fact remains that many athletes have had long, successful careers while taking marijuana on the side. Mark Stepnoski, a former offensive lineman with the Dallas Cowboys and Houston Oilers, told ESPN in 2003 that he was a frequent user of marijuana during his career. Stepnoski is an advocate for its legalization.
“I have used marijuana, and it's never prevented me from accomplishing what I wanted to accomplish,” he said.
Ellis, however, said he has collected considerable anecdotal evidence in analyzing body composition of athletes and that those athletes who have lost muscle mass or increased body fat are often involved in drug use. Ellis said it can have a noticeable effect on the ability of athletes to play well during the course of a long season.
“Marijuana users don't thrive like they should versus someone who can breathe normally,” Ellis said. “I don't think it's anything good for these athletes. We're talking about people trying to recover from one competition to the next. Anytime you have something that impedes oxygen transport or screws up blood pressure, then you've got endurance outcomes where these athletes are going to struggle.”
Vass, who has worked with top runners and players from the NFL, NBA and English Premier League soccer, acknowledged that many athletes smoke marijuana in order to reduce stress and relax when away from the court or field. But he said he believed taking marijuana, even during the offseason, can have an effect on performance at a later time.
”A true athlete is always in training mode,” he said. “Like [Redskins quarterback] Jason Campbell may take a little break between his last game and the Pro Bowl, but then it's time to go to work. Anything that happens in between affects the work he has to do. If you're trying to be a high level athlete, you need to stay clean during the off time or just retire.”