Marathoners at Slim Risk of Cardiac Arrest01/11/12
WEDNESDAY, Jan. 11 (HealthDay News) -- If you're a healthy
distance runner, your chances of dying from sudden cardiac arrest
during a race are extremely slim, a new study indicates.
In the last decade, one of every 259,000 runners who competed in
a U.S. marathon or half-marathon died, the researchers found. And
most who collapsed had underlying heart disease.
The findings should reassure those who participate in the sport
-- and many do, with more than 450,000 U.S. finishes a year,
according to David Watt, executive director of the American Running
The study began in 2000, led by Dr. Aaron Baggish, director of
the Cardiovascular Performance Program at Massachusetts General
Hospital in Boston. The researchers analyzed the cardiac arrests
suffered among competitors in marathons (26.2 miles) or half
marathons (13.1 miles) through 2010.
Of nearly 11 million U.S. distance runners, 59 had a cardiac
arrest, meaning their heart suddenly stopped beating. Forty
occurred in full marathons, and the average age of the stricken
runners was 42. Men were at significantly higher risk than
Forty-two of the cardiac arrests (71 percent) were fatal, found
the study, published in the Jan. 12 issue of the
New England Journal of Medicine. The average age of those who died was 39, compared with 49 for arrest survivors.
For the study, yearly statistics on race participation, provided
by the trade association Running USA, went into a database.
Researchers identified cardiac arrest cases through a combination
of methods, including public search engines and contact with race
They interviewed racers who survived cardiac arrest, or next of
kin, and looked at medical records and autopsy data. This
information was available for 31 of the 59 affected runners.
A condition called hypertrophic cardiomyopathy was the definite
or likely cause of death for 15 runners, they determined. The
condition is the most common cause of sudden cardiac death in young
Hypertrophic cardiomyopathy is essentially an overgrown heart
muscle, which usually comes from some genetic abnormality,
explained Dr. Kirk Garratt, clinical director of interventional
cardiology research at Lenox Hill Hospital in New York City.
Nine who died of hypertrophic cardiomyopathy had additional
heart conditions, such as obstructive coronary artery disease,
congenital disorders and myocarditis, an inflammation of the heart
"One interesting finding: prevalence of coronary artery disease was low," Garratt said.
One runner died of heat stroke and another of hyponatremia,
which can occur when a person drinks too much fluid, without taking
in enough sodium. Two were presumed to have died of arrhythmia, an
abnormal heart rhythm.
A key factor in survival was receipt of cardiopulmonary
resuscitation (CPR) from race bystanders, said Baggish, the
cardiologist for the Boston Marathon.
"We're actually going to be for the first time offering CPR training to runners this year who come to Boston for our marathon," Baggish said.
Prompt defibrillation is also crucial, said study co-author Dr.
William Roberts, a professor of family medicine at the University
of Minnesota and medical director of the Twin Cities Marathon. At
that race, "you're always within a mile of a defibrillator," he
Every year new races crop up, especially half-marathons, Watt
said. And they attract a different breed of runner.
"Today's runner is older, slower, committed to going to more events, possibly not as athletic," he said. Some are "experiential" or social runners who come to bond, race for charities or lose weight.
In the study, men had a cardiac arrest rate of 0.16 arrests per
100,000 runners, nearly double that of women, but still extremely
Garratt had some reservations about the study methodology. "They
went to a racing agency for the denominator. Then they went to a
variety of sources, including Internet-based sources. To make it
worse, for about half of the incidents, they were unable to get
complete clinical information," he said.
Roberts acknowledged that their data didn't take marathon
preparation into account. "How do we know how many people we lose
with shorter [training] races?" he asked.
He said that with proper conditioning, distance running "is safe
if you listen to your body, if you don't try to push through chest
pain or shortness of breath, or if you don't ignore factors like
very high cholesterol."
"All runners, whether they're young or old, should have a discussion with their doctors about their intent to run and in that discussion there should be a very clear assessment of risk factors," Baggish said.
The Cleveland Clinic offers advice on
marathon fitness preparation.
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