Free diving

[druiaghtagh]

I know that the ability to hold your breath is a pre requisite, but how do these divers get around the bends when surfacing a scuba divers have to have stops when ascending. Also ,how about the pressure at depth affecting them, any answers please?

[Sequin]

You only get excess nitrogen disolved in the blood if you breath gas at pressure - free divers do not breath underwater son only minimal amounts of nitrogen from the air in their lungs will disolve, not nearly enough to cause the bends (now call Decompression Syndrom - DCS)

At depth, their lungs will be compressed by the pressure - down to about the size of your fist, as will their abdominal organs. This does not happen to divers breathing compressed gasses, as it is delivered at the ambient pressure of the water

[Mattk]

it is an amazing spectacle.

i saw the female world champ(who i believe is better than the guys too!) 'packing' her lungs before descending and passing out.shows how borderline these amazing people are

[scubadiver]

The problem with breathing gas from SCUBA is that, as Sequin correctly points out, you are breathing at the ambient pressure of the surrounding water. The deeper you are, the higher the pressure.

The problems start on ascending. If this is done in a slow, controlled manner, the nitrogen that has been forced into solution in the blood is removed  by normal gaseous exchange in the lungs. If the ascent is too fast, instead of gaseous exchange taking place, the excess nitrogen for the lower pressure(ie, the shallower depth) tends to "bubble" out into the bloodstream, causing potential emboli, which are then free to move with the bloodflow and block any blood vessels which are too small for them to pass through.

This causes a DCI. The reason for this being commonly known as "the bends" is that the emboli often block blood vesels at joints. Apparently, relief from the pain can be gained by bending the joint - so divers with a DCI were often seen to be bent over in an effort to be comfortable.