From Mexico City to Denver's Mile High Stadium there's been lots of talk about how high elevation affects athletes. But researchers at California State University, Sacramento say declines in exercise performance can hit even closer to home - as low 1,900 feet.

Kinesiology and health science professor Daryl Parker, who conducted the study with colleague Roberto Quintana, says, "Decreases in exercise performance happen at much lower levels than had been thought. Previously, endurance experts believed there is no change in endurance until 5,000 feet or higher. The lowest altitude where we saw change was 1,900 feet."

Their discovery is a first for American researchers and confirms a recent finding by an Australian who came up with similar data, using different methodology.

It also has applications beyond the athletic arena. Parker says the decrease in blood oxygen experienced by people at high elevations is similar to what pulmonary patients and people with heart disease experience. By studying how people respond to altitude, it may be possible to better understand how disease processes work.

Besides turning conventional wisdom upside down on performance and altitude, the researchers are challenging another long-held theory - that a person's fitness level alone determines how they will perform at a high elevation.

It is widely accepted that the amount of decrease in performance depends on a person's cardiorespiratory fitness. And, though it may surprise some non-athletes, the expectation hasn't been that the fitter the person the better they'll fare. Instead, the research has demonstrated the higher the fitness level, the more capacity the person loses. But Parker and Quintana believe that another factor may be involved.

"There are two markers for endurance: VO2 max, which is the maximum amount of oxygen a person can consume in exercise, and lactate threshold, the highest steady state intensity a person can maintain for a long time," Parker says. Generally, Parker says, the more oxygen that a person consumes - meaning a high VO2 max - the larger the decrease in their exercise capacity at altitude. But people who can maintain a high steady state intensity for a long time - those with a high lactate threshold - seem to have less decline in exercise capacity at altitude.

The finding is big, Parker says since it overturns a previously held belief among athletes that high fitness was a liability to high altitude performance because of the resulting increases in VO2 max.

"They used to say, 'Why train if I'm going to compete at altitude?'," he says. "Now they may want to look at ways to train to increase lactate threshold in order to protect the amount of capacity they'll lose." The types of training that increase lactate threshold vary by fitness and activity type, Parker says, but could include intense intervals of hard exercise, long periods of easy exercise or both.

As for altitude training, "For the most part, it doesn't work," Parker says. "Don't train at altitude if you want to do well at sea level."

And unfortunately for new mountain dwellers, Parker says that even as they get more adjusted to the elevation, they will not be able to match what they were able to do at sea level. Their performance may get better, but their maximal exercise capacity won't increase.
For more information, contact CSUS public affairs at (916) 278-6156.