Athletes performing in the Vancouver 2010 Winter Games are obsessed with blood.
That's because blood carries oxygen to the muscles, so more blood means more oxygen—and potentially better Olympic performances.
But just as vampire transfusions can give True Blood characters an illicit rush, some athletes have been known to take doses of blood in illegal attempts to beat the competition. (Blog: "The True Story About Blood Donations—And Vampires.")
Known as blood doping, the banned practice involves getting a blood transfusion near game time to give yourself more, richer blood than nature can produce. (Find out how Vancouver 2010 athletes might also one day seek to alter their genes to enhance performance.)
There are two known types of blood doping. One uses ordinary transfusions, and that's easy to catch today, according to Harvey Klein, chief of transfusion medicine at the U.S. National Institutes of Health.
"You can look for the foreign cells. They have different proteins on their surfaces, and we have very sensitive methods of detecting those," Klein said.
A more sophisticated method is for an athlete to withdraw some of his or her own blood during training and store it, said Don Catlin, an anti-doping researcher who spent 25 years as head of an anti-doping laboratory at the University of California, Los Angeles.
The body then builds up replacement blood and, shortly before an event, the extra blood is injected back into the body. This method can sometimes be caught by tests that can tell if a person's hemoglobin—the protein in red blood cells that carries oxygen to tissue—is suspiciously high.
But athletes using this version of blood doping have been known to inject blood in the morning, race, then have the blood withdrawn later, thereby reducing their chances of being caught by random tests.
Blood Doping a Risk for Vancouver 2010
As far back as 1987, a study in the Journal of the American Medical Association found that some distance runners could improve by about 3 percent in 10-kilometer (6.2-mile) races if the athletes were given 400-milliliter blood transfusions beforehand.
(Related: "Building the Unbeatable Body" in National Geographic magazine.)
In the Vancouver 2010 games, blood doping would "probably help almost everybody, even figure skaters," Catlin said. "But the target group is cross-country skiers. They have had episodes of blood doping [in the past]."
No matter the perceived benefits, blood doping isn't just against the rules, it's dangerous. Transfusions done at home, for example, can incur the risks of contracting blood-borne diseases and getting sick from bacteria growing in poorly stored blood.
Doping can also make the blood dangerously thick, Klein said.
"When hemoglobin is too high, you run into many complications, the worst of which is clotting." In fact, he said, some athletes have died from efforts to overly enrich their blood.
"They probably became dehydrated, and their blood effectively 'sludged,'" he said.
More natural methods for building up extra blood include intense physical training, eating well, and either living at altitude or sleeping in "altitude tents" designed to simulate mountaintop living.
Although doping with your own blood will be harder to trace during the Vancouver 2010 events, the World Anti-Doping Administration will probably soon develop a way to beat both known forms of blood doping by testing for trace chemicals leached into the blood from storage bags, Catlin said.
"But as soon as they do, the crooks will find a way around," he said. "That's just the way the game works."