What effect does altitude have on Nitrox diving?

Altitude has a significant impact on Nitrox diving, primarily because of how it influences nitrogen off-gassing rates. At higher altitudes, the atmospheric pressure decreases, which in turn affects your body’s ability to eliminate dissolved gases, such as nitrogen, from your system after a dive.

When diving with Nitrox, which has a higher proportion of oxygen and a lower proportion of nitrogen compared to air, the off-gassing of nitrogen is critical to address, especially when a diver ascends to a higher altitude. The lower pressure at altitude means that nitrogen off-gassing occurs more quickly compared to diving at sea level, potentially increasing the risk of decompression sickness if ascents and surfaces are not appropriately managed.

This understanding is crucial for divers who plan to dive in locations at altitude or who may ascend to high altitudes soon after diving. It is important for divers to adjust their dive plans, surface intervals, and ascent rates accordingly to accommodate this change, thereby ensuring safety during dives.