In February 1995, it was estimated that "approximately 500 boxers have died in the ring or as a result of boxing since the Marquess of Queensberry Rules were introduced in 1884.
On April 2, 2005, Zerlentes was participating in the Colorado State Boxing Senior Female Championships (an amateur boxing contest) at the Denver Coliseum in Denver, Colorado.
She was knocked out in the third round by her opponent, Heather Schmitz, fell unconscious, and never regained consciousness.
Zerlentes is the first woman known to have died of injuries sustained during a sanctioned boxing match in the United States.
According to the Denver County coroner, the cause of death was blunt force trauma to the head.