Some
people find they have
a natural tendency to
hold tlieir breath when
they first begin learning
to use scuba, but this
tendencyus he changed.
The lungs can be injured
hy even Although
lung overexpansion injuries
are very serious and among
the most difficult diving
injuries to treat, they
are also among the easiest
to avoid: Simply breathe
at all times and do not
hold your breath when
using scuba.
During
your confined water dives
you'll practice some skills
during which you take
the scuba regulator out
of your mouth, but even
then you don't hold your
breath. Instead, you'll
learn to exhale a slow,
steady stream of bubbles
any time the regu-lator
isn't in your mouth.Your
other air spaces generally
pose no prob-lems during
ascent. Normally, expanding
air releases from these
without any conscious
effort.
It
is possible, though, to
feel pain and discomfort
in your ear and sinuses
while ascending due to
a reverse block, sometimes
called a "reverse
squeeze." A reverse
block occurs when expanding
air cannot escape from
an air space during ascent.
In this case, you feel
discomfort because the
pressure inside the air
space exceeds the surrounding
water pressure.
Reverse
blocks are uncommon and
generally result from
diving with congestion
cleared by medication,
and having the medication
wear off while underwater.
To avoid this, don't dive
with a cold or allergy
congestion, even if you
use decongestants or other
medication.
