Colo. (Dec. 9, 2013) – A new study shows that high school athletes playing at
higher altitudes suffer fewer concussions than those closer to sea-level, a
phenomenon attributed to physiological changes in the brain causing it to fit
more tightly in the skull.
is the first time any research has linked altitude to sports-related
concussion,” said Dawn Comstock, PhD, associate professor of epidemiology at
the Colorado School
of Public Health and co-author of the study. “It appears
that when you are at altitude there may be a little less free space in the
skull so the brain can’t move around as much.”
study, first-authored by David Smith, MD, of Cincinnati Children’s Hospital
Medical Center, was published recently in the Orthopaedic Journal of Sports
researchers analyzed concussion statistics from athletes playing multiple
sports in 497 high schools from across the U.S. with altitudes ranging from 7
feet to 6,903 feet with 600 feet being the median. They also examined football
separately since it has the highest concussion rate of high school sports. The
numbers came from the National High School Sports-Related Injury Surveillance
System which is directed by Comstock.
results showed a 31 percent decrease in concussion rates among all high school
sports played at altitudes of 600 feet and above. Concussion rates for high
school football players at these altitudes decreased by 30 percent.
did see significant differences in concussion rates with elevation changes,”
Comstock said. “This could mean that kids in Colorado are less likely to
sustain a concussion playing sports than kids in Florida.”
reasons for these declines are unclear, the study suggests a possible
explanation - as one ascends in altitude blood vessels in the brain undergo
mild edema or swelling. This swelling along with other physiological changes
cause the brain to fit more tightly in the skull so that it cannot move around
as violently when struck. Sports-related concussions usually result from the
brain colliding with the skull following a blow to the athlete.
edema in the brain leads to increased extravascular water,” the study says.
“These two adaptations would also lead to a tighter packaging of the brain with
increased blood cell content surrounding the brain.”
said the next step may be to look at professional sports.
this study is correct, we should look to replicate our findings in the National
Football League,” Comstock 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.”
incidence of concussion among high school athletes has grown tremendously. The
Centers for Disease Control and Prevention estimate the annual incidence of
sports-related traumatic brain injury in the U.S. at 1.6 million to 3.8 million
with many more going undiagnosed. In a recent 10-year period there has
been a 100 percent increase among 8 to 13-year-olds and a 200 percent increase
among 14 to 19-year-olds in sports-related emergency room visits for
said sports equipment hasn’t changed in decades and this study could possibly
pave the way for the design of new protective equipment to reduce concussions.
scientists found that putting mild pressure on a rat’s jugular vein increased
pressure on the brain and reduced injury from concussion by 83 percent.
are many possibilities here,” Comstock said. “But we are just beginning to
understand the connections between altitude and concussion.”