Many Olympic athletes take advantage of a loophole to the anti-doping rules that ban the use of performance enhancing drugs through a practice known as "legal doping," or taking legal prescription medications that may improve performance, according to NPR.
More than 100 athletes competing in the Olympic games have tested positive for traces of meldonium, a heart drug that improves blood flow, for example. Meldonium is the drug tennis champion Maria Sharapova admitted to using in March. She said she had been using the drug for a decade.
"You improve blood flow, you improve oxygen getting to the muscles that you want," Ronald Evans, PhD, director of the Gene Expression Laboratory at the Salk Institute in La Jolla, Calif., and an investigator for the Howard Hughes Medical Institute, told NPR. "Therefore, it's good for performance."
The World Anti-Doping Agency banned the drug in January, so Ms. Sharapova's later admission barred her from the Rio Olympics. However, the more than 100 athletes who tested positive for the drug can still compete because levels were low enough that they could be left over from use before the ban took effect, according to the report.
"If it's not banned, athletes will use it," said Dr. Evans, according to the report.
While it is not clear exactly how much advantage athletes get from taking meldonium, athletes are experimenting with a widening range of prescription drugs to get ahead.