Exposure to high altitudes has been long believed to benefit athletes during training. The higher the altitude, the less oxygen there is, meaning the body works harder to increase its oxygen levels. It is thought this process can lead to better athletic performance, but it has been unclear as to which altitude height is the most beneficial - until now.
A team of researchers, led by Benjamin D. Levine, of the Institute of Exercise and Environment Medicine, and James Stray-Gundersen, of the USA Ski and Snowboard Association, conducted a study involving 48 track and cross country college runners.
Their findings were published in the Journal of Applied Physiology.
The athletes trained for a 4-week period in Dallas, TX - a city close to sea level.
During this time, the athletes completed a series of tests that assessed areas of performance, such as their VO2max - a measure of aerobic fitness based on the rate at which the body uses oxygen during exercise.
Monitoring training at different altitudes
A new study suggests that athletes must train at altitudes between 2,000 and 2,500 meters in order to see any benefits from altitude training camps.
The athletes were required to run 3,000 meters at the fastest pace they could, and the researchers timed this activity.
They also conducted a series of blood tests. These involved measuring the concentration of erythropoietin (EPO) - a hormone that triggers the production of red blood cells - and the volume of red blood cells.
According to the investigators, living at higher altitudes causes a person's EPO levels to increase. In order for the body to adapt to less oxygen, the body needs to make more red blood cells.
When the tests were completed, the researchers divided the athletes into four groups and flew them to the mountains in Salt Lake City, UT. Each group was sent to training camps in the mountains, all of which were different altitudes.
The locations were:
- Heber City (1,780 meters)
- Park City (2,085 meters)
- Deer Valley (2,454 meters)
- Guardman's Pass (2,800 meters).
For another 4-week period, the athletes were required to train once a day, and their EPO concentrations were checked regularly.
At the end of the 4 weeks, the athletes returned to Dallas, where they were required to undergo further training and blood testing.
'Defined window' produces benefits
When looking at results at the end of the full study, the researchers found that the groups who trained at the two middle altitudes - 2,085 meters and 2,454 meters - performed much better, compared with those at the very lowest and highest altitudes.
Furthermore, every group demonstrated an increase in EPO concentrations and red blood cells.
The investigators suggest their findings oppose long-held beliefs that training at all high altitudes enhances performance. They suggest there is a "defined window" of altitude, which produces these benefits at sea level - between 2,000 and 2,500 meters.
Commenting on the findings, the study authors say:
"These data suggest that when completing an altitude training camp, there is an optimal living altitude for producing improvements in sea level performance.
For the athlete engaged in altitude training, the identification of an optimal living altitude holds tremendous practical application."
Earlier this year, Medical News Today reported on a study detailing the discovery of a gene that may explain why some people develop chronic mountain sickness (CMS) at high altitudes.