In the world of step goals and activity trackers, the number 10,000 can sound like a magic one. Many wearable devices that track the number of steps a person takes each day come pre-programmed with a daily goal of 10,000 steps. But while a large body of evidence shows that physical activity is good for a person’s health and longevity, few studies have examined how many steps a day are associated with good health, particularly long-term health outcomes. A new study led by investigators from Brigham and Women’s Hospital sought to address this knowledge gap by examining outcomes over an average of more than four years for older women in the Women’s Health Study