Developing research, as reported by Medical News Today, suggests that breathing pure oxygen can actually cause damage to the brain and heart; thereby exacerbating the problem that it has always been thought to prevent.
The air that is normally breathed does not contain high amounts of oxygen. In fact, the most abundant chemical in the air around most people is mainly nitrogen. Because the human body has developed in conditions that were not exposed to high amounts of oxygen, the body is not naturally equipped to handle such high concentrations of oxygen, notes Medical News Today. When oxygen is so high in the bloodstream relative to the concentration of carbon dioxide, this causes blood vessels in the brain and heart to constrict.