It's well known that in order to save lives, CPR needs to begin immediately after a person collapses or “witnessed arrest” occurs (when someone sees the event occur). But only approximately one-third or less of people respond in witnessed arrest situations, and even when CPR is begun immediately it is often done incorrectly. That's why it's important to become certified in CPR and Automated External Defibrillators (AED) and to take the recommended renewal certification classes. By learning CPR, you can help preserve life, limit disability, restore health, and even reverse clinical death in emergency situations.