The Sydneysider is no stranger to the Australian Running Festival, having completed her first marathon in 2015.

After a year of health hurdles discovering in 2016, getting the all-clear from doctors to take on this new 'first' was a real step forward.

In March last year the avid runner was out on a regular morning run when her heartbeat suddenly dropped from 140 bpm to a dangerous 40bpm.

"I was literally on the side of the road on the phone to my husband saying 'something is wrong with me, my chest is pounding, I feel like am going to pass out'," she said.

"It comes on very quickly which was a real worry because the majority of my training I do in the mornings alone."

Ms Swain was diagnosed with bradycardia, a slower than normal heart, and after careful monitoring went under the knife last October to have a pacemaker inserted.

It has been a step-by-step process to rebuild her running fitness, but an added challenge has been regaining her confidence to be out on the road alone.

"Running for me has never been about the sport, or weight loss but purely about getting out there and clearing my head," she said.

"The mental side of it has been really difficult. There were always those questions in my head: Am I right to go out? Am I right to keep pushing?"

Ms Swain has been running 10km each morning for the past week and said it felt good be back in the rhythm.

"I am easing back into it and still have enough time to be ready," she said.

"April I need to do for me. It's not about a time, but just getting a finish. It will still be a first and an upgrade on what I achieved a few years ago, so it will feel good to get across the line."

The Mudgee-born runner said she loved the scenic courses on offer at the Australian Running Festival.

"The feel of the Canberra course is the other appeal for me," she said. "It is like being at home running through the back of the Canberra hills. It is very similar to what Mudgee is like."

Entries are open now for the Australian Running Festival held in Canberra from April 8-9. Register now for the 5km, 10km, half-marathon, marathon and 50km ultra marathon events. Get in now to lock in a $20 Earlybird discounts before February 14.