Former England batsman James Taylor has said that he was "shot a few yards across the room" by his defibrillator.
Taylor was forced to retire from cricket aged 26 after being diagnosed with a heart condition in 2016.
He was fitted with an internal defibrillator in June for his irregular heartbeat, and he said it has since gone off on one occasion.
"I can't trust my heart. It's keeping me alive, just about, but it's being very temperamental," he told BBC Sport.
Addressing new members of the Professional Cricketers' Association in Birmingham, Taylor, now 27, said: "The defibrillator has kicked in with real force.
"It shot me a few yards across the room, probably because I'm small.
"That's probably why I've got the anxieties I have now and I'm a little bit scared of exerting myself or pushing myself in some way.
"I know the feeling when it does go off, when things aren't quite right. It's a scary feeling and it hurts. It does its job, that's the most important thing."
Taylor made seven Test and 27 one-day appearances for England before being diagnosed with diagnosed with Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC).
The condition means that he can no longer undergo vigorous exercise.
"I'm learning a new body and I'm learning what is a new heart, now, for me. I'm thinking more than I ever have," Taylor added.