You’ve probably seen people in the gym staring at their phones. Maybe you do it too. But being on your phone can decrease the quality of your workout and increase your risk of injury. In a study published in the journal PLOS ONE, researchers found that people who ran or walked while texting or talking on the phone were slower and had a lower average heart rate. Another study looking at people on their phones between sets during weightlifting found reduced strength output during the exercises. And a study published in Performance Enhancement & Health found that texting during exercise decreases postural stability by 45 percent, increasing your risk of falling and getting injured.