What might be a sign of oxygen toxicity during a dive?

Visual disturbances such as tunnel vision are a significant sign of oxygen toxicity, especially at higher partial pressures of oxygen encountered during dives using enriched air nitrox. Oxygen toxicity can affect the central nervous system, leading to symptoms like visual changes, seizures, and other neurological effects. Tunnel vision occurs when the peripheral vision is lost, leaving only a narrow field of sight. This can create dangerous situations during a dive, as the diver may have difficulty noticing their surroundings, leading to potential hazards.

The other choices are not indicative of oxygen toxicity. Increased muscle fatigue may result from general exertion underwater, while improved buoyancy and reduced air consumption rates do not correlate with the physiological response to excess oxygen in the system. Understanding these signs is crucial for divers using nitrox blends, as it allows them to better recognize the risks associated with higher oxygen levels and to respond appropriately to ensure their safety during their dives.