How does increased oxygen exposure affect dive duration?

Increased oxygen exposure significantly decreases feasible dive durations due to toxicity limits associated with higher partial pressures of oxygen. As divers descend and increase their exposure to oxygen at pressure, the risk of oxygen toxicity rises. Oxygen toxicity is a condition that can lead to symptoms such as visual disturbances, dizziness, and convulsions, and it becomes a particular risk when the partial pressure of oxygen exceeds 1.4 ATA (atmospheres absolute) during recreational diving.

Since divers need to manage their exposure to oxygen carefully to avoid these dangers, the time spent at greater depths, where the partial pressure of oxygen is higher, is limited. This is compounded by the consideration of safe ascent practices and surface interval requirements. Therefore, divers must use tables or dive computers that factor in these limits when planning dives to ensure safety, thus confirming the idea that increased oxygen exposure indeed shortens the viable duration of dives beyond what might otherwise be permissible.