As a respiratory therapist with extensive experience in managing patients' oxygen therapy, I can tell you that it is indeed possible to breathe too much oxygen. When the body is exposed to increased partial pressures of oxygen for a prolonged period, it can lead to a condition known as hyperoxia, which is an excess of oxygen in the body tissues. This overabundance of oxygen can be harmful and can cause central nervous system toxicity, which is the result of short exposure to high partial pressures of oxygen at levels greater than atmospheric pressure. It's important to regulate the amount of oxygen a person receives, especially in a clinical setting, to prevent such complications. read more >>

The result of breathing increased partial pressures of oxygen is hyperoxia, an excess of oxygen in body tissues. ... Central nervous system toxicity is caused by short exposure to high partial pressures of oxygen at greater than atmospheric pressure.read more >>