A wearable device monitors a wearer's physical activity and provides assistance to the wearer. The device includes physiologic sensors that provide sensor data of the wearer to a processor, a user interface that provides information to the wearer, a network interface that provides a network connection between the device and a remote computer, and a memory that stores instructions. The processor executes the instructions to collect physical activity data of the wearer using the sensors, to provide the collected activity data to the remote computer via the network interface to create or update a parameterized rule-based custom data model for the wearer, to receive the custom data model for comparison to collected activity data, and to communicate with the wearer via the user interface when a check of the wearer's activity data against the custom data model indicates that the wearer's activity is not consistent with the custom data model.