Pacemaker detected active minutes are superior to pedometer-based step counts in measuring the response to physical activity counseling in sedentary older adults oleh Venkata K. Puppala, Benjamin C. Hofeld, Amberly Anger, Sudhi Tyagi, Scott J. Strath, Judith Fox, Marcie G. Berger, Kwang Woo Ahn, Michael E. Widlansky