The rapid improvement in mobile health technologies revolutionized what and how people can self-record and manage data. This massive amount of information accumulated by these technologies has potentially many applications beyond personal need, i.e. for public health. A challenge with collecting this data is to motivate people to share this data for the benefit of all. The purpose of this study is to survey and examine factors that may motivate sharing this data. We asked 447 participants four questions related to health data sharing and motivation. Participants with a chronic disease were concerned about data sharing but also willing to share health data if personalized feedback is provided. Functionality, ease of use, and privacy are regarded as crucial features of health apps.