Decompression sickness, otherwise known as “the bends,” is an ailment usually associated with scuba diving, but the risks of such a physiological event are equally as great during high-altitude parachute jumps. Residual nitrogen in the bloodstream can, upon descent, turn into bubbles that can migrate throughout the body and cause pain, paralysis, and death. To prevent the onset of decompression sickness, they pre-breathed for an hour. Any nitrogen remaining in their bodies, even any ingested while switching oxygen tanks, could be deadly.
