PADI Divemaster Certification 2025 – 400 Free Practice Questions to Pass the Exam

When a diver descends to a specific depth, the increased pressure causes nitrogen, which is absorbed from the air we breathe, to dissolve into the body’s tissues. The physiological process of this nitrogen absorption is known as "saturation." At a given depth, if the diver remains there long enough, the tissues will reach a state of equilibrium, absorbing nitrogen until they are saturated with it.

This saturation happens because the partial pressure of nitrogen in the surrounding environment (the water) is higher than in the diver's blood and tissues. As the diver stays at that depth, nitrogen continues to diffuse into the tissues until the rate of absorption equals the rate of elimination, resulting in a balance known as saturation.

Understanding this concept is critical for divers, especially in relation to avoiding decompression sickness (DCS), which can occur when returning to the surface too quickly without allowing the nitrogen absorbed in the tissues to safely leave the body.