Older athletes speeding to the finish line may be racing toward

more than the end of a 10K: They may be racing toward the end of life, according to soon-to-be-published research outlined in The Wall Street Journal.

"Running too fast, too far and for too many years may speed one's progress toward the finish line of life," the paper quotes an editorial written for next month's British journal Heart.

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Researchers analyzed 52,600 runners and non-runners over three decades. Overall, the runners enjoyed a 19 percent lower death rate than their non-running peers, but the runners who ran a lot (over 20-25 miles a week) did not.

Another study, presented at a medical conference, found that running at a top speed of 8 miles per hour produced the most longevity benefits. And previous research has shown cardiac abnormalities in extreme athletes.

"After age 50, pushing too hard is probably not good for one's heart or longevity," study author and sports cardiologist James OiKeefe told the paper.

O'Keefe, 56, slashed his own workout regimen in accordance, although his co-author still occasionally pushes the limit.

"I train slower than I race, and when I race I know the risks," said Dr. Lavie, a cardiologist at the John Ochsner Heart and Vascular Institute in New Orleans. "That's all we're trying to do: Let people know the risks and make up their own minds."

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And not everyone agrees that there are risks. Critics say numbers of really fast, high-mileage runners are too few to be statistically significant.

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