Marathon man 'back from the dead'

A man who collapsed during the Sydney Running Festival over the weekend was clinically dead for six minutes, and brought back to life by paramedics.

In an interview with 7News from a hospital bed, Jamie Donaldson says he was told he had died, "I was told I was dead. Six minutes." he said.

Donaldson collapsed after completing the 21 kilometre race suffering a cardiac arrest, he was immediately treated by St John's paramedics at the Opera House finish line.

Reports say he was given CPR and treated with a defibrillator.

Dr Jonathan Cherry from St Vincent's Hospital says that Donaldson's collapse at the end of the race was crucial to his survival, "If he collapsed in the middle of the race with no people around, he wouldn't be talking to us right now. Very lucky." says Dr Cherry.

The cause of his cardiac arrest was said to be hot weather, low electrolytes and a race average heart rate of 184 beats per minute.

Donaldson claims he felt like he was struggling to complete the marathon, clutching his chest and gasping for breath, but says he disregarded the pains as part of the arduous marathon experience.

The 31-year-old Donaldson is a father of two children and says he will no longer compete in marathon running events.