Source: NASA

09-18-2008 17:13

Spacewalkers must wear pressurized spacesuits in order to work in space. These suits have pressures significantly lower than ambient cabin pressure of a spacecraft. This makes spacewalkers subject to decompression sickness, more commonly known as the "bends."

Decompression sickness results from nitrogen bubbles forming in the tissues or blood stream and moving to other areas of the body. Therefore, spacewalking crewmembers must perform a pre-breathe protocol, which is designed to wash out any excess nitrogen from the body, before a spacewalk.

This protocol takes advantage of the fact that exercise increases the speed at which nitrogen is removed from the body by increasing blood circulation through the extremities.

 

Editor:Liu Fang