Inclusion Criteria:  history of stage I-IIIA lung cancer; completed curative intent therapy (i.e., lung cancer resection surgery, definitive radiation, or concurrent chemoradiation) within 1-6 months; access to a mobile phone or personal computer with internet access; willingness to wear activity trackers  Exclusion Criteria:  dementia (or cognitive impairment identified by chart review) resulting in inability to follow directions or provide written informed consent; acute myocardial infarction, ventricular tachycardia, ventricular fibrillation, acute cerebrovascular event, or acute asthma exacerbation in past 2 months; spontaneous pneumothorax in past 12 months; Parkinson's disease; multiple sclerosis; amyotrophic lateral sclerosis; additional movement/gait disorders that may be identified by chart review