The journey to the top of Mount Everest usually takes more than a month. That’s because most climbers stop periodically to let their bodies adjust to the thinning air, which contains less oxygen (O) at higher altitudes. Last spring, a group of British climbers completed the trek in only five days! Two weeks before their expedition, they did something unusual: They inhaled a low dose of oxygen mixed with xenon (Xe)—one of the nonreactive noble gases.
Some research has shown that breathing in xenon can increase production of red blood cells. Having more of these cells to carry oxygen throughout the body may have made the climb easier. For weeks before their trip, the climbers also spent time in tents with low oxygen levels inside. Their speed “was likely a combination of everything they did to train their bodies,” says Andrew Subudhi, a biologist who studies sports medicine.