Stand Up requires access to your standing data in HealthKit in order to visualize the data for you. Your health data never leaves the security of your iOS devices; it is never transmitted to the cloud, and is not shared with any third parties.
Limited data on your use of the application is collected, solely for the purpose of identifying bugs in the application. This data is anonymized, and only available to the developer.
Any communication regarding the security of this data will be available in the application.