Which factor can increase the risk of decompression sickness?

Diving after flying increases the risk of decompression sickness due to the changes in atmospheric pressure and nitrogen absorption in the body that occur when flying. After spending time at high altitudes, the body can retain nitrogen absorbed during a flight. Following this, if a diver descends and experiences a rapid pressure change, the nitrogen may not be released from the body tissues and blood as effectively, leading to a higher likelihood of bubble formation. This is especially concerning if the diver is not adequately off-gassed after flying, which can contribute to the onset of decompression sickness.

In contrast, the other factors listed typically do not increase the risk of decompression sickness. Diving at lower depths generally reduces the exposure to pressure changes, while staying within safe diving times ensures adherence to recommended no-decompression limits, helping to minimize the risk. Using nitrox mixtures can enhance safety by decreasing the amount of nitrogen breathed, reducing the likelihood of nitrogen narcosis and decompression sickness during a dive, particularly at certain depths.