Karnazes, 43, to run 50 marathons in 50 days

LOS ANGELES -- Dean Karnazes insists he's
not crazy. He just loves to run. A lot.

This fall, the 43-year-old long distance runner will tackle
one marathon a day for 50 consecutive days, running a total of
1,310 miles. And for each 26.2-mile race, Karnazes and his family of four will travel to
a different U.S. state.

Arguably the world's best-known ultramarathoner, Karnazes
has already run 350 miles in one stretch, run a
marathon in the South Pole, and raced across the California
desert in the middle of the summer.

With this fall's challenge, however, Karnazes said on
Tuesday he is going a step further in testing the human body's

"I'm curious to see what the limits of human endurance
are," he said in an interview. "I still haven't found them."

To train, Karnazes said he logs anywhere from 80 to 175
miles of running a week around his home
in San Francisco. He has also picked up the pace of his racing
schedule in the last five months, averaging about two marathons
a month in addition to a range of ultramarathons, or distances
longer than 26.2 miles. This week, he'll tackle a 100-mile
race in Colorado.

"It's almost like designing an engine that can go 200 miles an hour for a 100-mile-an-hour race," Karnazes
said of his aggressive training regimen, adding that he
averages about four hours of sleep a night so that running does
not get in the way of spending time with his two children,
Nicholas, 8, and Alexandria, 11.

Beginning Sept. 17 with the Lewis & Clark Marathon in St.
Charles, Mo., Karnazes' so-called "Endurance 50" event
will take him to eight official marathons and 42 "re-created"
marathons across the United States.

Each marathon is expected to take around three-and-a-half
to four hours, Karnazes said.

Runners of any ability are encouraged to join Karnazes
along the way and can sign up online at the event's Web site,

Karnazes will end his quest with the ING New York City
Marathon on Nov. 5.

"I might actually log a couple extra miles," he said,
adding that the logistics of getting from race to race are
almost more challenging than the running itself.

Still, Karnazes insists that he's not crazy and that anyone
could undertake the types of physical challenges he has.

"I've had a couple of jaws drop," he said. "I really don't
consider myself to be gifted in any sort of way ... I just
really love to run."