Records and personal bests were blitzed by the elite competitors in near perfect running conditions in the 44th Chevron City to Surf for Activ today.

Even Foreign Minister Julie Bishop set a personal best putting a tumultuous week in Canberra behind her joining more than 20,000 other competitors as they ran, walked and rolled their way over the 4km, 12km, 21km or 42km distances from St Georges Terrace to City Beach Oval.

Local runner Matt Ramsden not only defended his title in the traditional 12km event but set a new race record of 35 minutes 23 seconds, eclipsing Brett Cartwright’s 2006 time by two seconds.

The 21-year-old, who has spent two months racing in Europe recently, said it was the conditions and his training regime that had made the difference this year in claiming the record.

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“I knew it would be quick today with no wind,” he said.

“I have also been training so well lately clocking up about 150km a week.

Country girl, 22 year-old Emily Witham from Esperance, took the women’s title in 42:21 but her time was just outside of Eloise Welling’s 2017 race record.

Welling, who was back to defend her title, cramped badly during the race and finished outside the placings.

The two-time Olympian said that she just had not done the training required as the reason for her cramps and slower time after taking a break after the Commonwealth Games in April.

The crisp temperature of just seven degrees at the 6am start of the marathon also helped Hong Kong-based Sydney runner Ashley Miles defend his title and set a personal best of 2:29:20.

“I have been waiting to do a race when it is under 10 degrees to chase my PB,” he said.

“It is nice getting away from the heat and humidity of Hong Kong.

“I just love this course, it is so picturesque which really helps keep your mind relaxed.”

Japanese runner Yoshiyuki Ono chased Miles home finishing second in 2:39.26.

South African Jacquie Kellerman was disappointed that she did not break the three-hour barrier with her 3:03:50 time - her first attempt at the full marathon in Perth after previous success in the 21km event.

Local gun Rochelle Rodgers won her third consecutive and fourth half-marathon title in a personal best by more than a minute in 1:17.35.

“I am just stoked with that effort,” the 31-year-old said.

Kenyan Isaac Birir pipped good friend and training partner William Chebon Chebor to win the men’s half-marathon title in 1:05.04. Both broke the previous record of 1:05:40 set in 2008.

“I don’t care where I finish as long as I beat him,” Birir joked at the finish.

Melany Smart set a women’s race record of 12:49 winning the 4km event with Luke Graves just missing the men’s record in 11:07.

Foreign Minister Bishop set a personal best for 12km in just over an 65 minutes and said the run had helped clear her mind after a testing week following her unsuccessful Liberal Party leadership challenge which resulted in a change of Prime Minister.

Asked if the run today was fuelled by some anger and frustration “that is why run everyday” was her reply.

The City to Surf started in 1975 with just a handful of competitors has raised millions of dollars for charity during that time.