PADI Divemaster Certification Practice Exam

Why is it important to know your approximate altitude when diving?

1. It affects your buoyancy

2. It changes your dive buddy

3. It affects decompression models

4. It helps in planning dive sites

The correct answer is: It affects decompression models

Knowing your approximate altitude when diving is crucial because it significantly affects decompression models. As altitude increases, so does the risk of decompression sickness (DCS) due to changes in ambient pressure. At higher altitudes, the atmospheric pressure is lower, which can influence how nitrogen is absorbed and released in the body during and after a dive. Decompression models are based on the relationship between depth, time, and the pressure at which a diver is operating. When diving at altitude, divers must use modified tables or dive computers that account for the reduced pressure to ensure safe ascent profiles. This adjustment is vital for planning the dive and managing safety stops correctly, as the nitrogen off-gassing process differs compared to sea level dives. While buoyancy can be influenced by altitude due to changes in water density, and dive site planning may be affected somewhat by altitude considerations, neither of these aspects directly impacts the decompression risk as significantly as understanding the changes in pressure that come with altitude. Additionally, the dive buddy remains the same regardless of altitude, as buddy teams are defined by diving practices rather than environmental factors.