Researchers have thrown tons of time and money into studying whether exercise has an effect on depression, but far less research has gone into how exercise might affect antidepressants. If serious athletes are upping their training, it could change how the drugs are metabolized in the body, and how much medication they should take at a given time, an interaction scientists are only now beginning to investigate.
For now, the research is thin. Though drug companies are required to submit data about the effects of drugs on pregnancy and other factors, they're not required to provide any data about physical exertion. "We know nothing about the majority of the drugs and their interaction with exercise," says Dr. Ira Jacobs, a professor and dean of the faculty of Kinesiology and Physical Education at the University of Toronto. With one in ten Americans taking antidepressants, and a constant effort to encourage patients to be more active, it's an important area of study—though only a handful of people are actively researching how they interact.
Jacobs spent 25 years of his career working for the Canadian Department of Defence researching topics like the effects of performance-enhancing drugs on special operations units. Anecdotally, he found that after troops deployed, they reported side effects from various medications that they had never experienced pre-deployment. It made him wonder how acute bouts of exercise might affect medication generally.
"People who are exerting themselves acutely all of a sudden are diverting blood flow to their muscles," he says. "Where it's coming from, among other organs, is the liver, one of primary organs where we metabolize drugs."
It's possible that as we exercise and move blood away from the liver, we metabolize our medication more slowly, meaning we may need less of it.
Last year, Ethan Ruderman, a then a graduate student under Jacobs' supervision, conducted a pilot study looking at the effects of one acute bout of cycling on sertraline, also known as Zoloft. He found that the drug was removed from the body slightly more slowly during exercise.
The study is very preliminary, and Ruderman cautions against making any conclusions based on the data—particularly for people who have a constant amount of daily exercise, as opposed to a single, intense bout—but it "does help to lay the groundwork for future studies in this area."
Though doctors still don't know a lot about how exercise affects antidepressants, Ruderman and Jacobs agree it's still worth discussing with your doctor. "If an athlete is getting an improper dose of anxiety/depression medication, this may impact their mood, ability and effort to train and practice, which will certainly impact their performance on game day," Ruderman says.