A 59-year-old Northern Virginia man died Sunday during the Nation’s Triathlon in the District, a race official said.

The man, a competitor, apparently had a heart attack or similar event, said Bill Burke, race director. The man’s name was not released.

After apparently bicycling for about five miles, the man pulled up about 7:45 a.m. to a rescue unit near Chain Bridge Road and Clara Barton Parkway NW. After saying he did not feel well, he “immediately went into cardiac arrest,” Burke said.

The man was taken to Sibley Memorial Hospital, where he died, Burke said.

The first leg of the triathlon, a swimming competition, was canceled this year because of Potomac River conditions after recent heavy rains.

Burke said the man was a coach for Team in Training, which helps people train for endurance events, while raising money for the Leukemia and Lymphoma Society.

Burke said the man’s death was the first in the six years the triathlon has been held in the District. Temperatures at the time were in the low 70s, and relative humidity at 8 a.m. at Reagan National Airport was 87 percent.