Want to breathe with unconstrained lungs, cruise over hills as if they were pesky speed bumps, and shave down your PR? Then you'll need to spend some time huffing and puffing in thin mountain air. Although there's no conclusive sweet spot for optimal elevation training, USA Track & Field has recommended that athletes live between 7,000 and 8,000 feet above sea level. Sparse oxygen at such altitude forces your body to increase its number of red blood cells, thus increasing the amount of oxygen delivered to muscles during exercise and improving performance.
Lately, some of the best runners in the country have been traveling abroad for their stints at altitude. Nick Symmonds said he trained for a month at around 6,000 feet in San Luis Potosi, Mexico, leading up to the 2014 indoor track national championships. Ryan Hall and his wife, Sara, flew to Addis Ababa, Ethiopia, to run at 7,000 feet in preparation for this year's Boston Marathon. Desi Linden trained in Iten, Kenya (elevation 7,900), for the same race.
But there are plenty of high altitude destinations stateside. Flatlanders ought to be cautious when traveling any of these places—and not just because of the lack of oxygen. Visitors often become residents. Marathoner Frank Shorter moved to Boulder, Colorado, in 1970 to prepare for the 1972 Munich Olympics, and Boulderites still see him on area trails.
Here are ten of our favorite places to run at altitude, from high to higher: