A software app for a mobile device is disclosed for alerting a custodian of a person to be protected of an emergency situation involving the person to be protected. The app includes software instructions for carrying out a method including: establishing a range of normal heart rates for the person using a heart rate monitor； detecting a heart rate for the person that is outside of the established range； activating at least one of a camera, a microphone, an accelerometer, and a location indicator on the mobile device carried by the person； establishing a wireless data connection between the mobile device and a communication network； and transmitting data to the custodian from the activated camera, microphone, accelerometer, or location indicator via the communication network. The app can notify a custodian of a medical or safety emergency as it is happening, giving that custodian the ability to immediately notify emergency personnel.
