The altitude at which athletes such as runners and cyclists compete has considerable effects on performance. Higher elevations mean thinner air, with the partial pressures of all gases relevant to physical activity, primarily nitrogen and oxygen, declining as a function of elevation above sea level. The rarefied air confers an advantage in some events because of lowered air resistance, but the lower oxygen levels begin to supervene at events lasting above a certain amount of time.
The Sprints
The 1968 Summer Olympics were held in Mexico City at an altitude of 7,350 feet above sea level. These Olympics were noteworthy for world records being set in the men's 100, 200 and 400 meters as well as many of the jumping events. According to UK Athletics coach Brian Mackenzie,100-meter sprinters enjoy an advantage of about one-tenth of a second at this elevation, compared with sea level, and 200-meter sprinters gain about a quarter of a second. At the world-class level, these small differences are significant.
Middle Distances
At high altitude, the effects of decreased atmospheric oxygen pressure begin to cancel out the effects of lowered air resistance in the 800-meter run. Jack Daniels, an exercise physiologist and author of "Daniels' Running Formula," has developed a conversion tool for determining equivalent performances at various elevations and sea level. For example, a time of 40:00 at sea level translates to a 41:16 at 5,000 feet and a 42:36 at 10,000 feet, meaning that runners lose about 15 seconds for ever 1,000 gain in elevation.
Long Distances
Running speed declines even more on a per-mile bases in the longer distances than it does in the middle distances. A runner capable of a 3:10:00 marathon at sea level, a pace equivalent to about a 40:00 10K, would be expected to run just under 3:20:00 at 5,000 feet and close to 3:30:00 at 10,000 feet. A study in the May 1999 issue of "Medicine and Science in Sports and Exercise" found that the decrease in performance of elite marathon runners at even higher elevations above 14,000 feet was the result of decreased oxygen utilization and reduced running economy owing to the increased mechanical work of breathing.
Benefits of Altitude Training
Many distance runners relocate from sea level to higher altitudes for a period of time to take advantage of the physiologic changes that occur after prolonged exposure to hypoxic conditions. When you spend several weeks at high altitude, your body manufactures more red blood cells, which carry oxygen from your lungs to your muscles, to compensate for the lower oxygen pressure of the air your breathe. Research published in the "Journal of Applied Physiology" has shown, however, that unless you can travel to lower elevations to do the intense speed work required for maximum sea-level performance, the benefits of altitude training are largely reduced or negated altogether.
References
- Brian MAC Sports Coach: Effect of Wind Speed and Altitude on Sprint Times
- "Journal of Applied Physiology"; Living High-Training Low: Effect of Moderate-Altitude Acclimatization With Low-Altitude Training on Performance; Benjamin D. Levine and James Stray-Gundersen; July 1997
- Olympic.org: Mexico City 1968
- Runworks: Running Calculator
- "Medicine and Science in Sports and Exercise"; Marathons in Altitude; Giulio Roi et al.; May 1999
