An Ohio Army National Guardsman died during training in Indiana, the military announced late Monday.
Capt. Brian A. Stillman was involved in a land navigation exercise at Camp Atterbury, Indiana when he collapsed around 12:30 p.m. Friday, according to the Guard.
Stillman, 43, lived in Norton near Akron.
Autopsy results determined the cause of death was a heart attack, according to National Guard spokeswoman Stephanie Beougher.
The soldier, a 19-year-member of the Guard, was an operations officer for the 2nd Battalion, 174th Air Defense Artillery Brigade in McConnellsville. He is survived by a wife and two children.
In recent years, the air defense unit has deployed to Washington, D.C., to safeguard the skies around the nation’s capital.
Additional information was not immediately available.