Saturday's high heat is suspected in the death of a young man after a half-marathon on Chicago's south side.
Zachary Gregory, 22, was one of 11 people taken to the hospital during the 13.1 Marathon Chicago, apparently overcome by the heat. Gregory died at the University of Chicago hospital.
The race began under a yellow flag advising runners of not-optimal conditions. Some runners did complete the half-marathon before it was abruptly ended with a black flag, because of the heat.
Ten aid stations with medical personnel and spray stations were along the 13-mile route, said Jessica Prah, a spokeswoman with US Road Sports & Entertainment Group.
The Dallas-based company also sponsors the Chicago Half-Marathon set to take place on Sept. 11.
Gregory's family said he was in great shape, and they can't understand why he died.
"We take some comfort in knowing he passed away doing something that he loved," said his father, Bruce Gregory. "People lose children all the time, but it's never easy."