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 percent 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.