TUESDAY, Dec. 10, 2013 (HealthDay News) -- Altitude may affect
an athlete's risk of concussion, according to a new study believed
to be the first to examine this association.
High school athletes who play at higher altitudes suffer fewer
concussions than those closer to sea level, researchers found. One
possible reason is that being at a higher altitude causes changes
that make the brain fit more tightly in the skull, so it can't move
around as much when a player suffers a head blow.
The investigators analyzed concussion statistics from athletes
playing a range of sports at 497 U.S. high schools with altitudes
ranging from 7 feet to more than 6,900 feet above sea level. The
average altitude was 600 feet.
They also examined football separately, since it has the highest
concussion rate of U.S. high school sports.
At altitudes of 600 feet and above, concussion rates in all high
school sports were 31 percent lower, and were 30 percent lower for
football players, according to the findings recently published in
Orthopaedic Journal of Sports Medicine.
"We did see significant differences in concussion rates with
elevation changes," study co-author Dawn Comstock, an associate
professor of epidemiology at the University of Colorado School of
Public Health, said in a UC Denver news release. "This could mean
that kids in Colorado are less likely to sustain a concussion
playing sports than kids in Florida."
The reasons for the lower concussion rates at higher altitudes
are unclear, but Comstock and colleagues offered one possible
explanation. They noted that sports-related concussions occur when
the brain collides with the skull when a player is hit in the
But as altitude increases, blood vessels in the brain undergo
mild swelling. This swelling, along with other changes, causes the
brain to fit more snugly in the skull. As a result, the brain does
not move around as violently when the head is struck.
Although the study found an association between playing sports
at higher altitude and lower concussion risk among high school
athletes, it did not prove a cause-and-effect relationship.
The next step in this research may be to look at professional
sports, according to Comstock.
"If this study is correct, we should look to replicate our
findings in the National Football League," she said. "For example,
if the Broncos play the Chargers in San Diego or the Dolphins in
Miami they should experience more concussions than when they play
here in Denver."
The American Academy of Family Physicians has more about