some reports, scuba divers do not appear to have
anaccelerated decline in lung function, according to
researchers at the German Naval Institute. "Obstructive
changes in lung function have been reported with
cumulative scuba diving exposure,"
Dr. Kay Tetzlaff, of the University of Tuebingen,
and colleagues write in the medical journal Chest.
To look into this, the researchers studied in 468 military
scuba divers and a comparison 'control' group of
122 military submariners, all
of them men. Specifically, the team tracked the
participants' decline over time in lung performance --
measured as the maximum volume of air expired in 1 second
(called the FEV1).
Tetzlaff's group conducted the tests in all of the
subjects on at least three occasions over a period of at
least 1 year. The average follow-up was 5 years.At the
start of the study, the lung function of divers and
controls was greater than the expected norm. Over the
study period, no significant difference in the decline of
FEV1 was observed between divers and controls.
Forty-three percent of divers and 33 percent of controls
reported a history of smoking, and
the investigators found that FEV1 decline was
significantly more rapid in smokers than in non-smokers.
The drop-off was also greater in subjects with
above-average FEV1 to begin with, and in those who were
above the average age of the group.
"It is worth mentioning that in the present study the most
rapid decline in FEV1 was found in smoking divers with a
baseline FEV1 above average," Tetzlaff's team notes.
The investigators conclude that "in healthy males with
normal lung function and an uneventful diving history,
there are no long-term deleterious respiratory effects.
This may be reassuring for millions of recreational divers
worldwide," they add.