What is 'the bends'?
Nitrogen from a diver's air tank increases in pressure as a
diver descends. For every 33 feet in ocean water, the pressure due
to nitrogen goes up another 11.6 pounds per square inch. As the
pressure due to nitrogen increases, more nitrogen dissolves into
the tissues. The longer a diver remains at depth, the more nitrogen
dissolves for any specific depth. Nitrogen gas is not utilized by
the body and builds up over time in body tissues. If a diver
surfaces too fast, the excess nitrogen will come out rapidly as gas
bubbles. Depending on which organs are involved, these bubbles
produce the symptoms of decompression sickness. The process is
similar to shaking a can of carbonated soda. If the pressure is
high enough, the carbon dioxide in the soft drink will emerge out
opening of the can as a gush of bubbles. The bends are joint pains
involving the arms or legs. Intensity varies from mild to severe.
Arms are more commonly involved than legs. The pain is most
prominent around joints and in the upper shoulder area. It is
sometimes relieved by direct pressure. This occurs because nitrogen
is released into the joints and muscles.
A small change is that the pressure inside a suba cylinder does
not change depending upon depth as it is nonflexible container.
However, the parital pressures of the gases breathed due change
once they exit the cylinder (i.e. are breathed).
DCS is caused from the gas a diver absorbs during a dive coming
out of solution in a divers tissue and thus bubbling. These bubbles
push on nerves in the body causing pain as well as an injury. The
two common types of DCS are know as Type I (pain only bends) and
Type II (central nervious system bends). It is likely a diver will
develop both. DCS is occurs due to excessive gas in the body
bubbling and exceeding the bodies capacity to deal with the