Men who run, cycle or play other recreational sports are 20 times more likely to die from a sudden heart problem than female recreational athletes, according to a new study.
Although it's been known that sports-related sudden deaths are more common among men, some researchers have believed that's due to fewer women playing sports in the first place, the lead author of the report said.
"I think our study is the first to demonstrate the low incidence of sudden death among women in the general population is not only related to a lower sport participation," said Dr. Eloi Marijon, who worked on the study at the Paris Cardiovascular Research Center at Georges Pompidou European Hospital.
He and his colleagues tracked sports-related sudden deaths among adults in France between 2005 and 2010. Those deaths were due to cardiac arrest - when the heart suddenly stops beating, often related to a pre-existing heart condition.
The researchers compared the number of deaths in each sport to the total number of French men and women involved in those activities, based on a 2000 national survey.
There were 775 sports-related sudden deaths during the study period, including 42 among women, the researchers reported Tuesday in the Journal of the American Medical Association.
That worked out to a rate of one death for every 2 million female sports participants each year, compared to about one death per 100,000 male recreational athletes.
Risk varied by sport for men but not women. For example, about five out of every 1 million male joggers and one per 1 million male swimmers died every year. Among women, there was less than one death for every 1 million participants in both sports.
"It's a curious finding," said Dr. Joseph Marek, a cardiologist from Midwest Heart Specialists in Oak Brook Terrace, Illinois.
Marijon, now a visiting scientist at Cedars-Sinai Medical Center in Los Angeles, said there are two possible explanations for the findings.
One is that men start their activity quickly and go 100 percent right away - rather than building up to vigorous exercise - more often than women.
The second hypothesis is that men are more likely to have buildups and blockages in the arteries that supply blood to the heart, putting them at risk before they step on to the field.
"We know that coronary artery disease is the most important factor to dying suddenly during sports," Marijon told Reuters Health.
Marek, who wasn't involved in the new study, called the difference in deaths between men and women "striking."
But he said any possible cause for that disparity is just speculation without more detailed autopsy data.
"Certainly, this isn't definitive," Marek told Reuters Health.
"It really provides fodder to say we have some questions here that need to be answered… Hopefully this would move things forward to have better registries and collection of data."
Many European countries screen teen and adult athletes before they play sports to look for underlying heart problems that increase the risk of sudden death. Such widespread screening programs have been proposed in the United States, but are controversial.
Marijon said the new study has implications for that discussion.
"These first findings just raise the questions of, if we go to a screening of the general population before sports practice, probably such screening should be different for men and women," he said.