Chardon, OHIO - An Ohio woman has admitted to exercising her husband to death.

Christine Newton-John, 41, forced her husband to swim in their home swimming pool in Ohio until he was so exhausted he had a heart attack.

A video of the scene showed Christine pulling husband James Mason, 73, around the pool by his arms and legs and refusing to let him leave the pool. Christine pleaded guilty to reckless homicide for her actions.

Police chief Joseph Stehlik said he counted 43 times that Christine refused to let James out of the pool.

He said: "The video is bone-chilling. The whole case is very sinister."

James and Christine had known each other for a number of years and married in 2006 – 13 years after Christine had undergone a sex change, and swapped her name from John Vallandingham and included the surname of singer Olivia Newton-John.