What is the most noticeable and immediate effect of oxygen toxicity?

The most noticeable and immediate effect of oxygen toxicity primarily impacts the central nervous system. When divers breathe high concentrations of oxygen, particularly under increased pressures, it can lead to a condition known as central nervous system oxygen toxicity. Symptoms may include visual disturbances, auditory changes, and physical symptoms such as muscle twitching or seizures.

While the lungs can also be affected by oxygen toxicity, particularly with prolonged exposure to high partial pressures of oxygen, the acute effects that are most immediately noticeable are those related to the central nervous system. Understanding this distinction is crucial for divers, as it helps in recognizing the signs of oxygen toxicity early and taking appropriate measures to mitigate risks.

Other bodily systems mentioned, such as the feet or the bones, do not experience immediate effects from oxygen toxicity, nor do they typically exhibit symptoms related to changes in oxygen levels. Therefore, focusing on the central nervous system's role in this scenario is essential for recognizing potential dangers in enriched air nitrox diving practices.