Though many of these happenings are understandably astounding and seem to contradict what the Bible says about death, the whole idea of this so-called "life after life" experience is based on the premise that these people died.
According to the medical profession, these individuals were clinically dead. However, medical science has not yet agreed on what constitutes actual death in a human being. Real death, according to the Bible, is total and complete unconsciousness—without memory, feeling, knowledge, or perception (Ecclesiastes 9:5, 10; Psalm 6:5). Therefore, it is evident that those who were revived to relate their experiences were not actually dead, but simply in an unconscious state.
Furthermore, science has discovered that the human brain and nervous system are actuated by electrical signals and impulses. The brain is dependent on a steady supply of blood and oxygen to function properly. When circulation and respiration are impaired or interrupted for even a few minutes, the brain begins to malfunction, and will eventually cease functioning altogether. It is thought by some researchers that the strange lights, sensations, perceptions, and the like, associated with "coming back from death" may be attributable to the electrical malfunctions of the brain and nervous system associated with the trauma of nearly dying.
We can have confidence in Peter's statement in Acts 2:29, 34 that not even David, a type of the Messiah, has ascended to heaven. Jesus Himself testifies in John 3:13: "No one has ascended to heaven but He who came down from heaven, that is, the Son of Man who is in heaven." The clear evidence of Scripture is that, after death, a person rests in the grave until the resurrection from the dead.