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 usin 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.
