As the USA Pro Cycling Challenge grabs our attention this week much will be made of the altitude and its effect on the riders. The entire race is run above 5000 feet (1500 meters), and much is above 7000 feet (2100 meters). These elevations create substantial limitations to the exercising athlete, and also makes for a great jumping off point for a discussion on energy systems and performance.
This weeks USAPCC fires off their third edition of the race with seven stages set against the back drop of the Colorado high country. The race starts around 8000 feet in Aspen, and continues its high altitude traverse of the Rocky Mountains, with stages routinely reaching 10,000 feet and above. Most of the pro teams racing have been preparing for the race by coming to altitude early to acclimate. Indeed several of the teams raced the nearly-as-high at the Tour of Utah, which is an ideal preparation. The cost and logistics of sending a race team to altitude for several weeks before a race certainly begs the question "what happens at altitude?" so let's look for some answers...
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Altitude Research
Chances are you have a passing awareness that altitude impacts performance, but the how and why are worth a review. The effects of altitude were generally ignored until Bob Beamon broke the World Long Jump record by as astounding 55 cms at the 1968 Olympic Games.That jump set the standard for over 40 years and represents one of those marquee moments in sports—a benchmark for all time, much like Eddy Merckx's World Hour Record, which was also set, not coincidentally, in the altitude of Mexico City in 1972 (as was Francesco Moser's 51.151K ride, although Moser admitted to doping for the ride in 1999). From these performances it is obvious to see the advantages of altitude, primarily less air resistance. But what about the disadvantages?
The common refrain is that altitude, specifically the decrease in available oxygen, stimulates production of Erythropoietin (EPO) by the kidney, which in turn drives the production of new red blood cells (reticulocytes) in the marrow of long bones to help attenuate the effects. While increased red blood cell production does occur, a 2001 study by Hahn et al. theorized that the net benefit of this gain varied between individuals and "averages little more than 1 percent."