What is a potential risk associated with diving at high altitudes using Nitrox?

Diving at high altitudes introduces unique physiological challenges due to changes in ambient pressure and gas behavior. When ascending from a dive site that is located at a high altitude, the body may be more susceptible to bends or decompression sickness if ascent rates are not properly adjusted. At elevation, the partial pressure of gases that a diver is breathing changes, impacting how nitrogen is absorbed and off-gassed.

Proper ascent rates become crucial to prevent nitrogen saturation from occurring, particularly because the nitrogen comes out of solution more quickly as the ambient pressure decreases during the ascent. Adjusting ascent rates appropriately helps ensure that gases off-gas efficiently and reduces the likelihood of nitrogen bubbles forming in body tissues, thus minimizing the risk of decompression sickness.

While decreased visibility underwater, increased risk of nitrogen saturation, and faster oxygen depletion are considerations in diving, the specific risk that is most directly influenced by altitude changes and the application of Nitrox is the need for differently adjusted ascent rates.