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RESEARCH, EDUCATION & MEDICINE
SAFETY 101
68
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WINTER 2017
Effects of Aspirin on Diving
By Peter Buzzacott, MPH, Ph.D., and Jim Chimiak, M.D.
M
y doctor recommended that I take an
81 mg aspirin (a “baby aspirin”) every
day. Has there been any research into
how this might affect recreational
divers’ risk of decompression sickness (DCS)?
Though there is insufficient space here to address every
aspect of this question, my colleague and I will address
a few of the major issues. First, whatever research paper
we read will likely have participants that differ in some
way from recreational divers (they might be Navy divers,
for example) or environmental conditions that differ
(they might involve hyperbaric chamber dives rather
than submersions). Therefore, whenever we look to
research for definitive guidance we look for a meta-
analysis that summarizes everything that has been shown
in gold-standard human experiments. Unfortunately,
there has not yet been a meta-analysis of predive aspirin
use in divers, so we must look at individual studies. This
is a bit like looking at photographs in that they show only
snapshots of particular moments and may not convey
the totality of what was going on at the time.
My colleagues and I found that giving rats a daily
dose of aspirin for two days before hyperbaric diving
reduced the incidence of DCS after a very specific
compression profile. The limitations of this single
study, however, outweigh the practical lessons we can
take from it. In particular, the profile was well beyond
what recreational divers might dive, the experiment was
in a chamber instead of in the water, the dose was very
high, and the signs of DCS in rats are different from
those commonly seen in recreational divers. Although
the results of this small study were not statistically
significant, the experiment did suggest that high doses
of aspirin might have a protective benefit (in rats).
1
This was a potentially important finding because in
2014 the U.S. Food and Drug Administration (FDA)
denied an application to recommend a daily dose of
aspirin for primary prevention of heart attack or stroke.
2
The FDA has approved recommending aspirin for
secondary prevention (in patients who had already had
a stroke or heart attack, for example), but it requires
more evidence before it will approve aspirin for primary
prevention (prescribed as a preventive measure to people
Divers who take aspirin should dive conservatively to
minimize their risk of DCI and be sure they are free
from congestion (i.e., have no difficulty equalizing).
STEPHEN FRINK