A 14-year-old North Augusta, S.C., Middle School student collapsed and died after a 200-yard jog during a physical education class.
Cody Fox was pronounced dead at the Medical College of Georgia Children's Medical Center in Augusta on Monday.
Aiken County, S.C., Coroner Tim Carlton said Fox was a healthy student and made no complaints Monday morning.
Although Fox had no known physical ailment, Carlton said he expects an autopsy to be performed Tuesday will show that a congenital heart defect, or something related, caused the boy's death.
The school says an emergency counseling team will remain at the school throughout the week.