Flying After Diving:
Rules, Risks & Safe Surface Intervals
Flying after diving poses a risk of decompression sickness (DCS) due to reduced atmospheric pressure at altitude. After diving, your body retains inert gases like nitrogen. Ascending to altitude too soon—such as flying or driving to mountainous regions—can cause these gases to form bubbles in your tissues, leading to DCS. Cabin pressures in commercial aircraft are typically maintained at altitudes between 6,000 to 8,000 feet, which is a significant reduction from sea level pressure.
DAN's Recommended Surface Intervals
Divers Alert Network (DAN) provides the following guidelines to minimize DCS risk when flying after diving:
- Single no-decompression dive: Wait at least 12 hours before flying.
- Multiple dives per day or multiple consecutive days of diving: Wait at least 18 hours before flying.
- Dives requiring decompression stops: Wait substantially longer than 18 hours; a 24-hour surface interval is suggested, but longer may be necessary.
Personal Best Practices
In my diving routine, I prioritize safety by not scheduling any dives on flight days, both on arrival and departure. This approach ensures ample time for off-gassing and reduces the risk of DCS.
Altitude Considerations Beyond Flying
Even ground travel to higher elevations after diving can increase DCS risk. For instance, driving over mountain passes or visiting high-altitude destinations shortly after diving should be approached with caution. It's advisable to apply similar surface interval guidelines as you would for flying.
Advice for New Divers
While it might be tempting to squeeze in one last dive before flying to maximize your trip, it's essential to consider the risks:
"It's not worth the potential money saved on a flight to risk DCS. Change your flight or skip the last dive."
Prioritizing your health and safety over additional dives or cost savings is a prudent approach every diver should adopt.
Final Thoughts
Adhering to established surface interval guidelines and incorporating personal safety practices significantly reduces the risk of decompression sickness when flying after diving. Always plan your dive schedule with these intervals in mind, and when in doubt, err on the side of caution.