What is Decompression sickness?
'''Decompression sickness''' is caused by [[Liquid bubble|bubbles]] which form in the blood and other body parts of people who have the [[pressure]] around them decrease too quickly. These bubbles may block the flow of [[blood]] and starve the body parts of [[oxygen]], or the bubbles may cause damage by [[stretching]], [[tearing]], or [[pressing]] on the affected parts. Decompression sickness is also called ''the bends.'' ==People affected (occupations)== Decompression sickness can happen to [[Underwater diving|underwater divers]] who spend a lot of time in deep water, and return to the [[surface]] too quickly for the [[breathing gas]]es [[dissolved]] in their bodies to escape without forming bubbles. People can also get decompression sickness if they are in a [[pressurised]] [[aeroplane]] or [[spacecraft]] and it is damaged and the air is lost. ==Prevention == Decompression sickness can be prevented by decreasing the [[pressure]] slowly. This allows the gases which have dissolved in the body to get out in the breathing air without forming bubbles. Divers do this by coming up to the surface slowly, as the pressure depends on the depth, and reducing the depth will reduce the pressure. For each ten metres change of depth the pressure will change by 1 bar, which is about the same as normal air pressure at [[sea level]]. Divers find out how slowly to come up by using decompression tables or a dive computer. They may need to stop on the way up to wait for enough gas to get out before it is safe to go up further. This is called a decompression stop. The tables or computer will inform the divers what depths they must stop at and how long they must stay at each depth. People flying high in aircraft avoid decompression by being in a pressurized cabin. In military aircraft the crew may breathe oxygen before the flight for a few hours so most of the [[nitrogen]] that is dissolved in their bodies can escape. This is called oxygen prebreathing. [[Astronaut]]s preparing for a [[spacewalk]] also prebreathe oxygen and dec