Multiple Flights after Diving

You’ve just finished a great dive trip in the Solomon Islands and now you’re preparing for the four back-toback flights needed to reach home. Think twice before you get on board — the recommended 24-hour waiting period after your last dive may not be enough.

“The problem of flying after diving goes way back, but the issue of repetitive flying has not been talked about much at all,” says Frederick S. Cramer, M.D., director of the San Francisco Institute for Hyperbaric Medicine. He presented a study about the effects of repetitive post-dive flights at the Undersea Hyberbaric Medical Society conference last summer.

Ascending to altitude means a decrease in pressure, causing the nitrogen that built up in a diver’s blood and plasma underwater to come out of those solutions and start bubbling. After touching down at sea level, the bubbles will get smaller but they won’t go down to predive levels right away because there is still surface tension between the bubbles’ exterior and the surrounding liquid. Multiple flights in one day after no-decompression dives means the bubbles will keep growing, Cramer says. “Say a bubble measures one-eighth of an inch before you fly. You go up to 10,000 feet and it grows to one-half inch. You come back down to the surface, but it only goes back down to one-quarter inch, so it’s not back to normal for a while. If you’re flying repetitively in a short timespan—and you keep going to higher altitudes— those bubbles will keep getting bigger.”

At the conference, Cramer presented a case study of a 37-year-old female diver from Couer d’Alene, Idaho. After 10 dives in the Caymans over six days with a 30- hour delay before flying, she began a four-leg trip back home. She flew in an unpressurized inter-island plane that rose to 5,000 feet and landed in Grand Cayman, situated at sea level. The second plane rose to 35,000 feet, maintaining cabin pressure at 8,000 feet, and landed at Miami, again at sea level. The third plane also flew to the same levels as the second but landed at Minneapolis, 1,000 feet above sea level.

That’s when she noticed “skin bends,” or nitrogen bubbles crawling like worms under the skin of her abdominal area. “That’s an early warning sign that the nitrogen bubbles are starting to come out of solution,” says Cramer. But the woman, herself a physician, chose to ignore the signs and boarded her fourth flight to Spokane, at an elevation of 2,400 above sea level. She arrived with a dull pain in her right shoulder, another major warning sign she again chose to ignore, so she could drive home to sleep.

Four hours later, at 2 a.m., she woke up with stronger shoulder pain, shortness of breath, chest pain and acute anxiety. She went to her local ER, and the attending physician, also a scuba diver, realized she was suffering from serious decompression sickness and got her into an hyperbaric chamber. After 285 minutes of treatment, the woman exited with all DCI symptoms gone. “But if she had canceled her flight to Spokane, stayed overnight at a airport hotel and had some aspirin and rest, this wouldn’t have happened,” says Cramer. “Early diagnosis is treatable but if ignored it can be fatal.”

Even though you may have waited 24 hours after your last dive, frequently going up and down in airplanes is dangerous because of the continuous bubble growth in your bloodstream. Going to a progressively higher altitude is worse. If you experience skin bends or headaches, stay off the plane. Consider breaking up your trips by staying overnight halfway through, and keep a constant watch for symptoms.