What are the Medical Dangers of Scuba Diving?

QUESTION: My husband has expressed an interest in learning to scuba dive; I'm
trying to discourage him, because I've read about so many medical dangers
involved. What do you say--are you on my side?
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ANSWER: After so many years in Family Medicine, I've learning not to take
sides in family discussions. But your husband is not alone; from 1975 to the
present, the number of scuba divers has more than doubled. No matter how
dangerous, it's not a sport we'll see disappear overnight. So the way to deal
with it is to discuss intelligently some diving-related injuries.
Some basic laws of physics are at the root of diving injuries. We know
that water pressure is double that of air pressure, and that as pressure
increases the volume of gases is inversely proportional. So during ascent and
descent in diving, the volume of gases in our body (oxygen and nitrogen)
changes rapidly. During a dive the volume of nitrogen in our blood and
tissues can double and then quickly halve. Decompression sickness or "the
bends" usually occurs within one hour after a dive, but it may not occur until
after twelve hours. Symptoms are pain, marbling of the skin, pulmonary
compromise, or central nervous system involvement. If left untreated, it can
lead to paraplegia, and most importantly it is not easy to diagnose. The pain
only variety usually occurs in the shoulder and elbow, and relief is found
when the joint is moved, hence the term "the bends." Another possible injury
is related to lung expansion. Going back to our laws of physics, as pressure
decreases, gases within the lungs of the diver expand; these gases must escape
or serious complications can occur. The last type of injury is called middle
air barotrauma or "squeeze", resulting from compression of the tympanic
membrane due to increased pressure.
Certainly, there are risks. But there are thrills and enjoyment as well.
Precise training, strict adherence to the rules, and constant vigilance can
lead to pleasure without injury. Now, with all this information, why don't
the two of you sit down and talk it through again?