November 6, 2009
This is Your Brain on Altitude
The New Yorker recently ran a disturbing article on brain injuries in football. Just about the same time, Outside magazine wrote about an alarming study of the effects of moderately-high altitude on climbers' brains. It has been known for some time that Everest climbers often show symptoms such as memory loss and poor coordination when they get home. And studies have found irregularities in the brain scans of 8000-meter climbers. The presumption has always been, however, that these effects lie exclusively within the domain of high altitude climbing (roughly defined as involving elevations of 22,000 feet or higher). The Outside article makes it clear this presumption may be dead wrong.
Researchers compared before-and-after brain scans of climbers who attempted 22,834-foot Aconcagua, 19,334-foot Kilimanjaro, and 15,771-foot Mont Blanc. To their surprise they found significant scan abnormalities (consistent with brain damage) on climbers from all three mountains, even Mont Blanc. The climbers who suffered the most damage were those with the least amount of prior acclimatization.
According to the study, the best recipe for brain damage is for sea-level residents to rapidly ascend to high altitude with no prior acclimatization. The good news, on the other hand, is that well-acclimatized climbers showed little to no ill effects on their brain scans, even when traveling to much higher altitudes.
I mention the New Yorker article above because it vividly demonstrates that severe brain injury can occur during activities we presume are safe. The NFL and others are discovering that it is not the high-profile hits that devastate an athlete's brain: rather, it is the daily and seemingly-innocuous pounding of ordinary football and practice that cumulatively adds up to debilitating effect.
It should be obvious that taking care of our brains is the number one priority of any sane health care program. Without a healthy brain, all else is moot. The studies referenced in the Outside article are not without their flaws, but they raise an alarm that must be taken seriously. Mont Blanc is slightly more than one thousand vertical feet higher than Mount Whitney. Only a fool would believe there is some sort of magic boundary between the two mountains whereby Mont Blanc climbers can suffer serious brain damage, but Whitney climbers are safe.
I should also stress that brain damage, unlike other injuries to the body, is permanent. The brain can rewire lost function to undamaged areas of the cortex, but for all practical purposes it cannot recover lost tissue.
These studies should serve as a wake up call to all of us regarding the importance of proper acclimatization, especially for the typical California climber, who will be driving to the mountains from near sea level and climbing high the same day. Obviously, we need more studies on the impact of climbing in the fourteen thousand foot range on the brain. We already know Climbers are unlikely to give up their sport even if brain damage is a probable consequence. But better information could dramatically reduce the likelihood and severity of damage.