What features of fitness trackers relate to coronavirus? HOUSTON When it comes to COVID-19, the most important measurement your fitness tracker takes throughout the day is your heart rate. Most smartwatches can identify when your heart rate fluctuates from its baseline and unexplained changes could signal a variety of health issues, including an infection. Does that mean your smartwatch can detect COVID-19? If that fitness tracker is motivating you to get your steps in, to get out and be active, thats a great way to boost your immune system, to stay healthier and hopefully keep coronavirus infections at bay, he said.