When more than one responder is available and trained in CPR, responders should switch roles under the following conditions:

• Approximately every 2 minutes, which typically corresponds to 5 cycles of 30 chest compressions and 2 rescue breaths. This timing helps prevent fatigue and maintains the quality of compressions.
• Whenever the original responder feels tired or shows signs of fatigue such as heavy breathing, soreness in arms or shoulders, difficulty maintaining proper compression rate or depth, reduced mental focus, or shallower compressions.
• The switch should be done quickly and smoothly, ideally during breaths, within about 5 seconds to minimize interruptions in chest compressions.

Clear communication and coordination during the switch are essential to ensure continuous, high-quality CPR, which improves survival chances. The second rescuer should be ready near the patient and take over immediately as the first rescuer finishes their cycle or indicates they are tiring. These guidelines align with the American Heart Association recommendations and recent CPR best practices to optimize rescuer performance and patient outcomes.