A 2006 study by Spanish neurologists Nicolás Fayed, Pedro J. Modrego, and Humberto Morales, reported in the April 2008 issue of Scientific American, found that MRI brain scans on 35 high-altitude climbers, including 13 who attempted Mt. Everest, found that every climber except one suffered brain damage and loss of brain cells from the lack of oxygen or hypoxia at high altitudes. What’s alarming is that even climbers who exhibited no symptoms of acute mountain sickness, including nausea, headache, dizziness, and fatigue, and appeared to be well acclimatized, still had brain damage.

Brain Damage Also at Lower Elevations

Besides Himalayan mountaineers, the study also looked at climbers on Aconcogua, the 6,962-meter high point of the Western Hemisphere, and 4,810-meter Mont Blanc in the European Alps. The researchers found that a significant number of climbers had brain damage at these relatively lower elevations. R. Douglas Fields, a neurobiologist at the National Institutes of Health (NIH), writes, “The study suggests that chronic exposure to high altitudes is not required to experience irreversible brain damage.”

Minimize Time at Altitude

The lesson, if you want to keep all your brain cells, is to minimize time at high altitude, to descend if you begin to suffer from altitude sickness, and to acclimate yourself before going higher. Dr. Fields notes that you could suffer brain damage by going from sea level to 14,000 feet in a couple days since the human body wasn’t designed for such radical changes. Instead plan your climbing trip up America’s Fourteeners like Pikes Peak, Mt.

Whitney, or Mt. Rainer by taking it easy for a few days at a moderate altitude and let your body and brain adjust to the thinner air.