The right answer is 5 - 10 seconds. The heartbeat check according to ACLS should not take more than that.
The steps for checking your heartbeat are: Have a watch. It will be used to measure your heart rate.Choose a place to take your pulse. It is better to choose either the neck or the wrist. Place your fingers so that you feel your heartbeat. Choose a duration for the measurement (5 to 10 seconds). Start counting. Multiply the number by 12 if you counted for 5 seconds (by 6 if it is 10 seconds).
