Live high, train low -that's the guide to faster legwork according to a paper published lastmonth in the Journal of Applied Physiology. The study shows that runnners can shave crucial seconds off their times if they live at high altitudes but train closer to sea level.

The body adapts to life in the thin air of high attitudes by generating additional red blood cells, which transport oxygen. Attempts to add to athletes' oxygen-carrying capacity by having them live and train at high altitudes have generally met with little success. High altitudes can cause insorrmia and suppress appetite and can prevent athletes from using their muscles intensely enough to get a benefit.

Benjamin Levine and James Stray-Gundersen, physiologists at the University of Texas South-western Medical Center in Dallas, wondered if it would help to live at high altitudes but train at low ones. To test the idea, they first timed 39 amateur competitive runners (27 men and 12 women) in a 5-kilometer race at sea level. Then they divided the runners into three groups: One lived and worked out at sea level, another lived and trained at 2500 meters, and the third lived at 2500 in but trained at 1200 Monday.

After 4 weeks, the researchers retimed the runners on the 5-km race at sea level. Those individuals who trained in the high-high and low-low conditions did not improve as a group. But the highlow runners took an average of 13 seconds off their total timeequivalent to about a 100-yard gain in a race.

Inspired by early study results, some athletes including Scandinavian skiers are already using a variation on the technique. George Brooks, an exercise physiologist at the University of Calfornia, Berkeley, says the researchers "are to be commended for this work," which he says is the first study with enough people to give valid results.