Several years ago, David Nieman set out to study racers at the Western States Endurance Run, a 100-mile test of human stamina held annually in the Sierra Nevada Mountains of California. The race directors had asked Nieman, a well-regarded physiologist and director of the Human Performance Laboratory at the North Carolina Research Campus, to look at the stresses that the race places on the bodies of participants. Nieman and the race authorities had anticipated that the rigorous distance and altitude would affect runners' immune systems and muscles, and they did. But one of Nieman's other findings surprised everyone.
After looking at racers' blood work, he determined that some of the ultramarathoners were supplying their own physiological stress, in tablet form. Those runners who'd popped over-the-counter ibuprofen pills before and during the race displayed significantly more inflammation and other markers of high immune system response afterward than the runners who hadn't taken anti-inflammatories. The ibuprofen users also showed signs of mild kidney impairment and, both before and after the race, of low-level endotoxemia, a condition in which bacteria leak from the colon into the bloodstream.
These findings were "disturbing," Nieman says, especially since "this wasn't a minority of the racers." Seven out of ten of the runners were using ibuprofen before and, in most cases, at regular intervals throughout the race, he says. "There was widespread use and very little understanding of the consequences."