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.