How does high altitude affect a diver before diving at sea level?

Diving from high altitude can present unique challenges due to the difference in ambient pressure compared to sea level. When a diver is at high altitude, the atmospheric pressure is lower than it is at sea level. This reduced pressure affects the way gases, particularly nitrogen, are dissolved in the body tissues.

When the diver descends to sea level, the increased pressure can cause the nitrogen that was previously at a lower pressure in their body to come out of solution more quickly. This rapid change can lead to an increased risk of decompression sickness (DCS), commonly known as "the bends." DCS occurs when nitrogen bubbles form in the body due to a decrease in ambient pressure, causing various physiological issues. Therefore, a diver coming from high altitude, where their nitrogen levels were stable under lower pressure, faces a greater risk of DCS when transitioning to higher pressure conditions experienced at sea level.

This is why recognizing the impact of altitude on diving is crucial for divers to manage their safety effectively before engaging in dives.