Decompression sickness, or the bends, "is a condition that develops when an excess of nitrogen has dissolved in body fluids and comes out of solution as bubbles of gas when a diver surfaces." (p 28, Culliney and Crockett) Decompression sickness, although less serious than rupturing a lung, has, on occasion, been fatal. It brings intolerable pain and recurring bouts of the bends. Even when it is not severe it could progressively damage parts of the body, such as, the heart, brain, bones, and nerves.
To explain the cause of bends we need to combine Dalton's, Henry's, and Boyle's Laws. "With the increasing depth, the partial pressure of nitrogen also increases (Dalton's Law). As the partial pressure of nitrogen elevates, it accordingly becomes more soluble in the tissues of the body. (Henry's Law) At depth, the diver with nitrogen dissolved in the tissues and blood-stream experiences no apparent problems.
On ascent, however, significant pressure/volume changes occur. (Boyle's Law)" (p 91-92, Griffiths) If you go up faster than the nitrogen bubbles can escape then they will expand or "bubble out" of solution. Several things could cause a person to be more susceptible to decompression sickness. If a person has a physical feature that limits circulation or respiration which would let the body absorb more nitrogen, which, in turn, would maximize the formation of bubbles. Other specific factors that would increase your chance of developing bends is excess fat (adipose tissue), drinking alcohol before diving, smoking, physiological aging, excessive fatigue, poor health, and exceedingly cold water. Also, the greater amount of fat (ration of fat to total body weight) you have on your body, in comparison to your body weight, the more susceptible you are because nitrogen is more soluble in fat than other tissues of the body.