How does a recent diving history affect flight?

• A. Diving history has no impact on flight decisions
• B. Divers should always fly immediately after diving
• C. Diving only affects flight if symptoms present
• D. Recent diving increases risk of decompression sickness during ascent; permit waiting period before flying

Answer: (D)

Nitrogen dissolved in your tissues from a dive can off-gas as you ascend and as cabin pressure in a flight drops with altitude. Flying soon after diving lowers ambient pressure further, which can cause dissolved nitrogen to form bubbles in blood and tissues, increasing the risk of decompression sickness during ascent. Because of this, a waiting period before flying is advised after any dive, with the length depending on how deep and how long you dived and whether you had repetitive or decompression-stop dives. Typical guidance is about 12 hours after a simple no-decompression dive, longer if you did deeper or multiple dives or required decompression stops. So, recent diving raises the risk and you should permit a waiting period before flying.