Thousands of school children in more than a hundred and ten schools across the county are being trained in lifesaving skills today.
It is part of the Yorkshire Ambulance Service's annual Restart A Heart Day, which has helped a 100,000 people learn to help those who have suffered a cardiac arrest over the last five years.
Lizzie Jones - whose husband Danny died three years ago from an undiagnosed heart condition - joined in with one of the sessions in Halifax along with Paralympian Hannah Cockroft.
Father of two Neil Davidson from Halifax was also at the event. He fell ill in the middle of the night last year and says he owes his life to the actions of his son Oliver. He said if his son had not have had CPR training he would have died. Jonathan Brown reports.