Patients will be given a commercially-available fitness tracker to wear continuously throughout the course of the study. Per this study's inclusion criteria, all patients will be treated with concurrent chemoradiotherapy for a malignancy of the brain, head and neck region, lung, gastrointestinal tract, or cervix. Patients will be randomized to one of two arms: an experimental arm, where they will be instructed to meet a daily, customized step count goal, or a control arm where they will wear activity trackers but be given no specific instructions to increase their activity levels. Patients in the experimental arm who fail to meet their step count goal for three consecutive days will be contacted by a study coordinator and reminded to try to meet the activity goals. If the patient reports that his or her activity is limited by treatment-related toxicities, the patient's treating physicians will be notified to ensure that supportive care needs are being met. With such a program, this study aims to demonstrate the potential to improve patients' ability to tolerate curative concurrent chemoradiotherapy without treatment interruption.