Tour de France

[Biowatch]

>>Have you ever watched free divers or breath-hold athletes preparing for their efforts? It's worth googling around -- there are video clips you can find on the web. Before a record attempt, these guys will hyperventilate for quite a stretch -- they're doing this to "pre-oxygenate" their blood to the maximum extent possible. (see #3 above). Then when they go to take their "big breath", they take the breath, hold it (using the tongue to seal the airway so no air from the lungs escapes while grabbing another mouthful), then add to it forcibly one mouthful at a time. It looks very much like a "gulping" exercise, like the way a fish out of water looks. They are forcibly expanding the lungs beyond the capacity they reach on a normal inhalation.<<

Keep in mind that it is the free divers that hold their breath, not scuba divers using compressed air. You add an atmosphere of pressure for every 33 feet of water you go down, so if a scuba diver doesn't exhale all the way up, the air in their lungs will expand and cause them to rupture.

Before it was a sport, pearl divers used to have amazing capacities in this regard, but that was work.

You have to be careful not to pass out from hyperventilating. Training can compensate for this. The ability to relax when doing maximum effort, rather than getting stressed out, may be key.

Some free divers have died after they surface for physiological reasons.

You do need the CO2 build up in your lungs to remind you to inhale again.

http://www.oar.noaa.gov/spotlite/archive/spot_diving.html

I've read Lance slept in a hypobaric tent to increase the hemoglobin content in his blood, and of course the Olympic training center is in Colorado Springs for the same reason, and the cycling team rides in Leadville, Colorado.