CLEAR FOR TAKE­OFF

Fast facts about the risks of fly­ing af­ter div­ing

Asian Diver (English) - - Research, Education & Medicine - By DAN Asia-Pa­cific

HOW LONG SHOULD YOU WAIT?

Fly­ing shortly af­ter div­ing can in­crease the like­li­hood for a diver to ex­pe­ri­ence symp­toms of DCS. There­fore, DAN’s safe div­ing and travel prac­tices rec­om­mend a wait­ing pe­riod that varies in du­ra­tion de­pend­ing upon the type and in­ten­sity of the div­ing per­formed.

These guide­lines ap­ply to divers who have no symp­toms of de­com­pres­sion sick­ness (DCS) and will be fly­ing at cabin al­ti­tudes of 610 to 2,438 me­tres.

Why are some divers more sus­cep­ti­ble to DCS?

You may have heard of divers who fly less than 12 hours af­ter div­ing with no neg­a­tive im­pact and oth­ers that wait a longer pe­riod who end up with symp­toms of DCI and won­dered why this hap­pens.

Dr John Parker, a div­ing physi­cian and Se­nior Dive Med­i­cal Con­sul­tant for DAN, ad­vises that there is no con­clu­sion as to why some in­di­vid­u­als are more sus­cep­ti­ble to DCS. How­ever, in­creas­ing age and BMI have been shown to be as­so­ci­ated with in­creased post-dive bub­ble, and the pres­ence of a patent fora­men ovale (PFO) is known to in­crease the risk up to six­fold, de­pend­ing on the size and char­ac­ter­is­tics of the PFO.

There may be some ge­netic fac­tors af­fect­ing sus­cep­ti­bil­ity. How­ever, in­di­vid­ual sus­cep­ti­bil­ity can also vary from day to day de­pend­ing on fac­tors such as ex­er­cise, hy­dra­tion, al­co­hol, smok­ing and anx­i­ety.

As a gen­eral rule, DAN AP rec­om­mends that divers wait at least 24 hours be­fore fly­ing af­ter div­ing. How­ever, min­i­mum guide­lines are as in­di­cated in the pre­vi­ous page.

What about div­ing af­ter fly­ing?

It can of­ten take a long time, and sev­eral flights, to get to some dive des­ti­na­tions but some divers are known to be­gin div­ing im­me­di­ately when they ar­rive to max­imise the time they have avail­able. The ques­tion is: Does do­ing so put them at greater risk for de­com­pres­sion ill­ness?

Mild de­hy­dra­tion can oc­cur on long flights, es­pe­cially when trav­ellers cross sev­eral time zones; al­co­hol con­sump­tion can also con­trib­ute to de­hy­dra­tion. Gen­er­ally speak­ing, de­hy­dra­tion is thought to pre­dis­pose a diver to de­com­pres­sion ill­ness be­cause the washout of in­ert gas (ni­tro­gen, in div­ing) is less ef­fec­tive in a de­hy­drated in­di­vid­ual.

If there were a re­la­tion­ship be­tween div­ing af­ter fly­ing and DCI, we would ex­pect to see a great deal of de­com­pres­sion ill­ness on the very first day of div­ing; this has not been ver­i­fied to date, and many DCI cases oc­cur af­ter sev­eral days of div­ing.

Although no one can in­sist upon a 24-hour wait­ing pe­riod af­ter fly­ing, such a con­ser­va­tive ap­proach to div­ing af­ter fly­ing is a rea­son­able idea as it gives divers an op­por­tu­nity to re­hy­drate, ad­just to a new cli­mate and time zone, and rest up af­ter a long flight.

NOTE that longer sur­face in­ter­vals fur­ther re­duce DCS risk

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