That "heavenly" light at the end of the tunnel may have more to do with carbon dioxide than an afterlife, a new study finds. Slovenian researchers studying near-death experiences found that people who reported seeing their life—or light—flash before their eyes had higher levels of CO2 in their systems. Up to 25% of cardiac patients report having such experiences.
The study, which followed only 52 patients, found an association between seeing light and higher levels of carbon dioxide, but that does not mean CO2 necessarily caused the effect, scientists pointed out. However, the findings seem to mesh with previous work on the link between the carbon dioxide and hallucinatory experiences. "It is potentially another piece of the puzzle, although much more work is needed," one scientist tells the BBC. (Read more death stories.)