What is the effect of increasing the percentage of oxygen within a gas mixture for divers?

Increasing the percentage of oxygen within a gas mixture for divers directly affects the risk of oxygen toxicity, rather than nitrogen narcosis. When divers use a gas mixture with higher oxygen levels, like enriched air nitrox, they actually increase the risk of experiencing oxygen toxicity if the partial pressure of oxygen exceeds safe limits. The body metabolizes oxygen efficiently at normal atmospheric levels, but higher concentrations can lead to toxic effects, especially at increased depths. Divers must carefully compute their exposure to these higher levels of oxygen pressures to avoid negative health effects.

On the other hand, the options regarding nitrogen narcosis, bottom times, and energy levels do not accurately correlate with the increase in oxygen percentage. Nitrogen narcosis, which relates more to nitrogen levels in the mixture and pressure, actually decreases with higher oxygen mixtures at shallower depths, while allowing longer bottom times is a potential benefit at safe oxygen levels, not solely from an increase in percentage without constraints. Similarly, oxygen levels do not inherently enhance a diver’s energy levels in a direct manner. Proper understanding and management of gas mixtures are essential for safe diving practices.