A Toronto nurse is being credited with helping to save a 23-year-old woman's life after she collapsed before the finish line of a 10-kilometre road race Sunday.

Jules McKernan was a spectator, waiting near the finish line of the Sporting Life 10K Run when she saw a woman collapse.

Two of her friends helped the woman and McKernan, who works as a transplant nurse at Sick Kids hospital, was going to run for help, when she realized someone was already on their way. She turned back to the woman.

"I heard, ‘She doesn't have a pulse,'" McKernan recalled in an interview with CP24 on Monday.

Together with her friends, McKernan worked on getting the woman's airway open and another friend started chest compressions.

"Somebody came in and said ‘I'm a doctor' and he took over compressions," said McKernan.

McKernan swapped spots with the doctor. He did artificial breathing, while McKernan continued with chest compressions.

McKernan said all she was thinking of in that moment was her training and her desire to keep the young woman alive.

"All it was, doing compressions, was push hard and push fast," she said.

McKernan said she was relieved when they finally got a pulse back and the woman started to breathe again.

"I definitely felt a bit of pride," McKernan said. "I think she's going to be OK."

The race director confirmed that the woman who collapsed is in stable condition and is expected to survive.

A spokesperson for the EMS said it is not uncommon for someone to collapse at a race, but it's usually an older male participant, not a young woman.