Altitude Training

Altitude training is the popular practice in which individuals train at extremely high altitudes, generally 2400 meters or more above sea level. It has been exploited by elite endurance athletes such as runners, triathletes, cyclists, etc. for nearly 50 years, in order to improve their performance. Interestingly, its origin can be traced back to the 1968 Summer Olympics in Mexico City, located 2,249 meters above sea level. The performance of athletes in several sprint events was extraordinary, breaking several existing world records. Despite being unable to pinpoint the exact reasons for the unusually enhanced performance, coaches did observe that the increased altitude did permit their athletes to perform much better and began including altitude training sessions as part of their regimen.

Interestingly, its origin can be traced back to the 1968 Summer Olympics in Mexico City, located 2,249 meters above sea level. The performance of athletes in several sprint events was extraordinary, breaking several existing world records. Despite being unable to pinpoint the exact reasons for the unusually enhanced performance, coaches did observe that the increased altitude did permit their athletes to perform much better and began including altitude training sessions as part of their regimen.

The underlying basis for the superior performance is the difference in atmospheric pressure at sea level and high altitude. At sea level, the air is denser, and there are more gas molecules per unit volume. However, with an increase in altitude, the pressure exerted by these gases decreases. Hence, there are fewer gas molecules per unit volume which generates an effective decrease in partial pressures of gases in the body. This is responsible for the physiological adaptation of the body to the change in altitude.

Despite decades of research, there are still ongoing debates about the exact physiological mechanisms which lead to improved performance. The vast majority of researchers attribute it to an increased blood cell volume, although some researchers do present a strong case for alternate mechanisms that elicit a shift to a more economic mode of oxygen utilization.

Proponents of the increased blood cell theory suggest that the body acclimates to the relative lack of oxygen by increasing its reserve of red blood cells and hemoglobin. The hypoxic conditions at high altitudes trigger hypoxia-inducible factor 1 (HIF1) to initiate the production of erythropoietin (EPO). This then stimulates the production of red blood cells in the bone marrow which increases the hemoglobin saturation to deliver limited oxygen more effectively. As a result, even when athletes return to sea-level, the additional hemoglobin remains in the bloodstream for about 10-14 days, and can effectively deliver oxygen. However, some researchers claim that altitude training stimulates a more efficient use of oxygen in the muscles through angiogenesis, glucose transport, glycolysis, and pH regulation. Some studies show that increased altitude can also alter the transcriptional regulation of certain genes, which results in changes in mitochondrial properties in skeletal muscles leading to improved performance.

In spite of this, there exists a consensus among sport scientists about the fundamental basis as to why altitude training actually works. Exposure to an environment of relatively low oxygen induces certain physiological adaptations. This ultimately leads to improved transport and utilization of oxygen, and over time it can result in increased speed, strength, recovery, and most importantly endurance responsible for the competitive edge in endurance races.

However, it's not all sunshine and rainbows, and altitude training is not the far-reaching panacea that certain overtly enthusiastic fitness enthusiasts claim it to be. Exposure to prolonged hypoxia can lead to deterioration of skeletal tissues which negatively affects the performance of athletes. Moreover, even the benefits of training are short-lived as the red blood cell concentration returns to normal within weeks. There is a trade-off in the intensity of training, which has to be compromised in such high altitudes. As with any form of exercise, what works for one individual, may not for others. This is especially true with altitude training because different individuals react to hypoxic stress differently. People physically tolerant to lower levels of oxygen might see slower and reduced results.

So while altitude training may not be the all-encompassing magic bullet that people frequently rave about, it is not without some appreciable advantages. With a proper, personally tailored training regimen, the positive benefits of altitude training can be exploited to give athletes the required edge and endurance, to naturally (and legally) enhance their performance.