BURBANK (CBSLA.com) — A teen boxer died Thursday following a workout at a San Gabriel Valley gym.

Raul Alvarez, Jr., 16, was brought to Saint Joseph’s Medical Center Thursday evening, complaining of pain from light sparring while boxing at Pullman’s Gym, which is located at 4320 West Magnolia Boulevard in Burbank.

“While at the hospital, the male suddenly went unconscious. All efforts by medical personnel to revive the male were unsuccessful and he was pronounced dead at the hospital about an hour later,” Sgt. Darin Ryburn of the Burbank Police Department said.

Alvarez and his sparring partner where both wearing protective headgear and regulation boxing gloves, Ryburn said.

Officials have not released how the teen died.

The Los Angeles County Coroner’s office and Burbank Police are investigating his death.