In a move that could have serious implications for the training methods of endurance athletes, the executive committee of the World Anti-Doping Agency will discuss the possibility of banning the artificial simulation of altitude conditions at a meeting in Montreal on Saturday.

Following up on a recent review by the agency's scientific committees and ethical issues review panel, WADA's executive board may determine that the the use of artificially-induced hypoxic conditions be included in the agency's draft 2007 List of Prohibited Substances.

Endurance athletes, especially cyclists, distance runners and cross country skiers, use the chambers to simulate high altitude conditions while they are resting or sleeping. Manufactures like New York-based Hypoxico, Inc., make a full array of altitude-simulating products, including tents which fit over beds, a cubicle which completely covers a bed, masks which can be worn to reduce the amount of oxygen an athlete breaths, or a fixed chamber which can cover an entire work space. The company can even convert entire rooms into altitude chambers, simulating altitudes of up to 3800 meters (12,500 ft.).

The use of the chambers, which is currently permitted, is controversial because it artificially raises red blood cell counts by using a medical device. The chambers have a big advantage over athletes living at altitude: it makes sea level training more convenient. Some studies have shown the best benefit from altitude training comes with sleeping and resting at altitude, while doing the actual training at lower altitudes. High altitude training for runners sometimes slows down an athlete's leg speed because workouts cannot be done at the same speeds as at sea level.

Hypoxico, on their website, list a number of top endurance athletes who use their products, including retired cyclist Lance Amrstrong, triathlon Olympic medalist Michellie Jones, marathon world record holder Paula Radcliffe and miler Suzy Favor Hamilton.

Hamilton, who is on maternity leave, is quoted by Hypoxico on their website: "Since I've been using my altitude-simulating tent, my personal best times have come down quite a bit and workouts feel easier after sleeping in it over a period of a couple of weeks. It's great sleeping at altitude here in Wisconsin!"

The U.S. state of Wisconsin is almost entirely at sea level.

The World Anti-Doping Agency constantly modifies their list of prohibited substances, and sometimes removes substances which have been previously banned. The entire family of Olympic sports has accepted the WADA anti-doping code as have have most professional sports.