Christchurch jockeys Terry Moseley said he was chatting to Invercargill trainer John Reece about his horse.
“He said ‘I need a beer, I’m hot’. All of a sudden, his head hit my shoulder and he dropped like a stone.”
Mr Moseley said he rolled Mr Reece over and cleared his airways before urgently seeking medical help.
Meanwhile, jockey Corey Argue undertook CPR until St John ambulance officer Dave Hay arrived and used a defibrillator to re-start Mr Reece’s heart.
Mr Hay said the machine was an important factor in saving Mr Reece’s life.
Mr Reece’s horse, Midnite Murma’s, had finished second at Wingatui 20 minutes before he collapsed.