The heartbeat is the pulsation of blood through a heart muscle. Some people, recognizing that fertilization is too soon to define the beginning of personhood and that birth is too late, look to the heartbeat as a possible marker. The heartbeat as a definition of personhood is flawed for three main reasons. First, a person can indeed be alive and not have a heartbeat because of a heart attack. Second, a person can be dead and still have a heartbeat because of brain trauma. Third, a heartbeat can exist outside of and separate from a person (see the video on this page). A heartbeat is not an appropriate measure of personhood because it can exist outside of and separate from a person.