Deirdre Larkin breezes through Johannesburg's suburbs most mornings, her white hair buffeted by the wind as she runs her well-trodden 8km training course.

At 85 years old, this retired concert pianist who only began running in later life can complete a half marathon in just over two hours and holds the world record time for her age.

"Before I turned 78, the last time I ran was in college, and I was really bad," she said, standing in her home in front of a wall of some 500 medals recognising her athletic feats.

Stopping for selfies with children and to offer her fellow runners encouragement, Larkin has become a major draw at the races she runs.

"As people pass me, because most people pass me, they greet me and say 'hello - I saw you on TV!'" she said following a recent 10-km race in Pretoria.
To stay in shape, Larkin adheres to a strict regimen - no sugar, salt or coffee and a 5:00 am start every day for training.

Last year alone she ran in 65 races, including several 21km half-marathons.
"There's always an element of disbelief. I can't believe I've done it. But my body tells me the next day I certainly did it," she said.

And despite preparing to turn 86 in September, Larkin has no intention of slowing down.

"I can imagine a life without running but it's a kind of slow death," she said. "I'm going to run as long as I can - even if I only have one leg, I'll manage."