Newsflash: Your pre-workout Tylenol could be sabotaging your health

Training for a race—whether it’s a mile or a marathon—can take a pretty significant physical and emotional toll on you. And although there are loads of ways to combat the associated muscle soreness and inflammation (think ice baths or the talk of the last Olympics: cupping), one of the most popular ways is to pop a Tylenol and let it do the rest of the heavy lifting so you can focus on actual heavy lifting.

But if Tylenol, ibuprofen or over-the-counter pain relievers (called nonsteroidal anti-inflammatory drugs, or NSAIDs) are a regular part of your pre-workout routine, there are some science-backed reasons to stop popping the pills. In addition to being a possible cause of bloating, two recent studies point to some not-so-pleasant side effects.

Ultramarathoners who took a Tylenol before running 50 miles “were about 18 percent more likely to have developed an acute kidney injury than the racers swallowing a placebo.”

According to The New York Times, a study published in the Emergency Medical Journal found that ultramarathoners who took a Tylenol before running 50 miles “were about 18 percent more likely to have developed an acute kidney injury than the racers swallowing a placebo.” The second study, published in the Proceedings of the National Academy of Sciences, looked at the effects of NSAIDs on mice and found that “anti-inflammatory painkillers might slightly impair muscles’ ability to regenerate and strengthen after hard workouts.”

In other words, that Tylenol that you take to combat inflammation and muscle soreness could be overworking—and consequently damaging—your kidneys, making it harder for them to do their job. And when your kidneys aren’t functioning well, everything suffers (including your muscles’ ability to build strength).

So while an NSAID is fine to take occasionally, relying on an OTC pill to curb soreness may not be your best bet, especially if you’re an adrenaline junkie or endurance athlete. And hey, you never know when you might accidentally run a marathon.

Instead of an Advil, think about harnessing the power of an herbal tincture post-workout, or try meditation.