Hold the painkillers, bring on the exercise
Taking ibuprofen and related over-the-counter painkillers could have unintended and worrisome consequences for people who vigorously exercise. These popular medicines, known as nonsteroidal anti-inflammatory drugs, or NSAIDs, work by suppressing inflammation. But according to two new studies, in the process they potentially may also overtax the kidneys during prolonged exercise and reduce muscles’ ability to recover afterward.
Anyone who spends time around people who exercise knows that painkiller use is common among them. Some athletes joke about taking “vitamin I,” or ibuprofen, to blunt the pain of strenuous training and competitions. Others rely on naproxen or other NSAIDs to make hard exercise more tolerable.
NSAID use is especially widespread among athletes in strenuous endurance sports like marathon and ultramarathon running. By some estimates, as many as 75 per cent of long-distance runners take ibuprofen or other NSAIDs before, during or after training and races.
But in recent years, there have been hints that NSAIDs might not have the effects in athletes that they anticipate. Some studies have found that those who take the painkillers experience just as much muscle soreness as those who do not.
A few case studies also have suggested that NSAIDs might contribute to kidney problems in endurance athletes, and it was this possibility that caught the attention of Grant S Lipman, a clinical associate professor of medicine at Stanford University and the medical director for several ultramarathons.
NSAIDs work, in part, by blunting the body’s production of a particular group of biochemicals, called prostaglandins, that otherwise flood the site of injuries in the body. There, they jump-start processes contributing to pain and inflammation. Prostaglandins also prompt blood vessels to dilate, or widen, increasing blood flow to the affected area. Taking NSAIDs results in fewer prostaglandins and consequently less inflammation and less dilation of blood vessels.
Whether these effects are advisable in people exercising for hours has been uncertain, however.
So for one of the new studies, published Wednesday in the Emergency Medical Journal, Lipman asked 89 participants in several multiday ultramarathons around the world to swallow either an ibuprofen pill or a placebo every four hours during a 50mile stage of their race.
Afterward, he and his colleagues drew blood from the racers and checked their levels of creatinine, a byproduct of the kidneys’ blood filtering process. High levels of creatinine in an otherwise healthy person are considered to be a sign of acute kidney injury.
The researchers found that many of the ultra runners, about 44 per cent, had creatinine levels high enough to indicate acute kidney injury after running 50 miles.
But the incidence was particularly high among the runners who had taken ibuprofen. They were about 18 per cent more likely to have developed an acute kidney injury than the racers swallowing a placebo. Furthermore, their injuries, based on creatinine levels, tended to be more severe.
The study did not follow the racers in subsequent days or weeks, but Lipman believes that they all recovered normal kidney function soon after the event ended.