"He had no pulse, no heartbeat. There was an ICU nurse there doing compressions."
Mr Mutu said he shaved the man's chest, hooked up the monitor, gave him the shock and "brought him back around".
Within four to five minutes his heart had stabilised and he'd regained full consciousness. An ambulance arrived a few minutes later.
Mr Mutu said everyone at the scene did "the right thing" and it showed just how important it was there was first response gear available.
"He's lucky he had his cardiac arrest at the carpark rather than in the middle of the forest because that could have been a different story."
Mr Mutu said they always had staff on site that had training in pre-hospital emergency care - and 80 per cent of staff at the business were at that level.
Providing the first response was something they did on a voluntary basis. Mr Mutu said much of the equipment was raised through fundraising with the Rotorua Mountain Bike Club.
They were now looking at fundraising to purchase a second defibrillator for the other side of the forest.
The first responders are called out to between 200 to 300 events a year which range from broken bones through to serious events.
Mr Mutu said he hadn't spoken to the man whose life he helped save, but understood he had returned to Wellington where he was undergoing tests.
