How long should divers avoid flying after completing a dive?

The guideline of avoiding flying for 12 hours after completing a dive is rooted in the need to allow sufficient time for excess nitrogen absorbed during the dive to safely eliminate from the body. When divers descend and ascend, they experience changes in pressure which can lead to nitrogen dissolving into body tissues under high pressure. If a diver were to fly soon after diving, the reduced atmospheric pressure in an aircraft could increase the risk of decompression sickness (DCS), commonly known as "the bends."

This 12-hour recommendation provides a buffer to ensure that decompression and any potential for gas bubbles forming in the bloodstream are minimized before exposure to a significant altitude change. This is particularly important for deep or multiple dives, where the risk of DCS increases.

The other suggested durations (6 hours, 10 hours, and 24 hours) do not align with the general medical advice based on research and expert recommendations. While 24 hours is a more conservative approach, especially for more complex dives, the standard guideline of 12 hours fits within the established safety protocols for recreational diving.