英文阅读：登山对大脑不利？
你是一个登山运动的爱好者吗?那你以后可要三思而后行了。一项新的研究表明攀登海拔很高的山，会损害大脑细胞，并影响运动机能。If you’ve ever fantasized about scaling Mount Everest, think again. A new
study of professional mountain climbers shows that high-altitude climbing causes
a subtle loss of brain cells and motor function.
Italian researchers used magnetic resonance imaging to look at the brains
of nine world-class mountain climbers who had at least 10 years of experience,
including expeditions to Mount Everest and K2. The climbers ranged in age from
31 to 52, with an average age of just under 38, and were used to climbing to
altitudes of at least 4,000 meters (two-and-a-half miles, or over 13,000 feet)
several times a year.
The scientists, who published their findings in the October issue of the
European Journal of Neurology, compared the climbers’ M.R.I. brain scans with 19
age- and sex-matched healthy control subjects. A number of neuropsychological
tests were also carried out to assess the climbers’ cognitive abilities,
including memory and motor functions.
On scans, the climbers showed a reduction in both white and gray matter in
various parts of the brain. Overall, the researchers found that the cognitive
abilities that were most likely to be affected were the climbers’ executive
function and memory.
Six of the nine climbers had lower than average scores on the Digit Symbol
test, which measures executive functions. Three out of nine scored lower than
average on memory tests, while four scored below average on a visual-motor
function test. The study authors noted that the results “are most likely to be
due to progressive, subtle brain insults caused by repeated high-altitude
exposure.”
Other studies have shown links between brain problems and repeated exposure
to extreme conditions. The British Journal of Sports Medicine reported in 2004
that scuba diving may have long-term negative effects on the brain, particularly
when performed in extreme conditions, such as cold water, more than 100 dives
per year, and diving below 40 meters.
And last year, researchers at New York University noted that high-altitude
illness is a growing concern in sports medicine given the increasing popularity
of extreme sports like high-altitude mountaineering, skiing and snowboarding.
The report noted that about 20 percent of tourists to Colorado report acute
mountain sickness, and complications arising from sports activities at high
altitudes, such as the potentially fatal conditions of pulmonary and cerebral
edema, are on the rise.
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