If you often run with music, or podcasts, or while watching television on the treadmill, you might want to listen up—literally. New research supports the idea that auditory and visual distractions while running may raise your risk for leg injuries.

The findings aren't terribly surprising. It makes sense that the more things we have on our minds while working out, the less careful we may be about our form, biomechanics, obstacles in the way, or how hard we’re really working. But this may be one of the first times researchers have compared distracted versus non-distracted running in a lab setting, and really quantified the results.

To test their hypothesis that distractions could interfere with safety, researchers from the University of Florida asked 14 experienced runners to run on a treadmill three separate times—once while watching a screen that flashed different letters and colors; once while listening to words spoken by different voices; and once with no background images or noise. For both distraction scenarios, they were asked to pay attention and identify certain letter-color or word-voice combinations.

The researchers noted that when the runners concentrated on those distractions, they applied force to their legs at a faster rate, compared to when they had a single focus. They also tended to breathe heavier and have higher heart rates while distracted. During the listening scenario, they also experienced an increased amount of force from the ground—meaning they came down harder with each foot fall.

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The results, presented at the annual meeting of the Association of Academic Physiatrists in Las Vegas, are preliminary and have not yet been published in a peer-reviewed scientific journal. The authors didn’t look specifically at whether these things really do lead to sports injuries. But they say it’s certainly possible—and runners who often train or race with with music, crowd noise, or lots of other people, may be particularly vulnerable, they say.

Sometimes this type of background noise can’t be helped, of course—and sometimes you just really need Spotify to get you though long training runs. But it may be smart not to pile too many new sights and sounds on at once, says lead author Daniel Herman, MD, PhD, assistant professor in the University of Florida's Department of Orthopedics and Rehabilitation.

“For example, when running a new route in a chaotic environment such as during a destination marathon, you may want to skip listening to something which may require more attention—like a new song playlist or a podcast,” said Dr. Herman in a press release.

This isn’t the first research to suggest a downside to distracted running: A recent pair of studies found that texting or talking on the phone negatively impacted both balance and workout intensity. (Listening to music, however, did not.)

The bottom line? Be careful out there, and be sure you’re giving your workout the attention it needs.