Two men running in the Chicago Marathon required CPR and one was in critical condition, according to the race's medical director.

Dr. George Chiampas says both runners were still alive as of late Sunday afternoon.

He says a 59-year-old man was in critical condition at Mercy Hospital on Chicago's near South Side after requiring CPR late in the race.

A 29-year-old man who had to be shocked after being stricken around the seventh mile was stable and talking to staff at Advocate Illinois Masonic Medical Center on Chicago's North Side. Chiampas says another runner — possibly a doctor — had already started CPR by the time medical personnel arrived.

Chiampas says over 800 runners needed medical care and 24 were taken to hospitals.