Learning how to save a life is a vital skill, but one third of people say they would not attempt CPR on someone who is suffering a cardiac arrest.
Northern Ireland Ambulance Service and the British Heart Foundation are teaming up to teach 5000 people CPR as part of 'Restart a Heart' day.
School children in south Belfast are among those learning the life-saving skill.
CPR saved Joanna's life
Joanna Ireland's life was saved by leisure centre staff when her heart stopped six months ago during a fitness class.
Joanna was taking part in her weekly 'Step and Hoop' class when she "went down like a sack of potatoes".
Five members of staff were called for help when Joanna stopped breathing.
They performed CPR for 25 minutes before an ambulance arrived to take Joanna to hospital; keeping her heart beating and breathing oxygen into her lungs prevented Joanna from any long-term disabilities.
Busting the myths around CPR
Stephanie Lecky works for NI Ambulance Service and trains others to perform CPR.
She says "doing something is better than doing nothing".
Stephanie says many people are worried about the consequences of performing CPR.
"People are scared. They're frightened they might hurt the person, they think what if I make them worse, or they're scared of being sued.
"What we want to say is if you find someone that's collapsed and they're not breathing - clinically they're dead and you want to try and make that situation better.
"You can't make it any worse, so try and do something," said Stephanie.
Joanna suffered seven broken ribs when the leisure centre staff performed CPR on her, but she says if they hadn't of broken them, she wouldn't be alive today.
She's urging others to just try - it's what kept her alive.
Learning the skill
Pupils enjoyed learning how to perform CPR and said it's a skill they'll now have for life.
Craig Moore from the British Heart Foundation said "we're determined every pupil in Northern Ireland and secondary school has the opportunity to learn CPR."
- Paul Reilly reports: