The persuasive powers come from her sister, Megan Sharplin, 57, an accountant from Auckland.
"I hadn't even thought of it. Megan said she was going to do it and needed some company so I said I'd do it, too."
That was only a fortnight ago.
But Parnell won't be walking alone today.
Also in the 10km walk mix are husband Cam, 71, a retired sports retail outlet manager and her sister-in-law, Margaret Evans, 62, of Puketiritiri.
"Cam came on board after me but the rest of them had already decided to do it," she says, agreeing she didn't want to be left out.
The rest of the clan who are lacing up for the half-marathon include Parnell's daughter, Lisa Cave, 44, a chartered accountant in Auckland, niece Fiona Evan (Margaret's 38-year-old chartered accountant daughter from Gisborne), brother-in-law and Megan's husband, Vern Sharplin, 59, the fleet manager of Air New Zealand in Auckland, and Megan's daughter, Emma Sharplin, 27, a calendar manufacturer's employee, and her partner, Carlos Delgado, 34, a Chile-born restaurant manager, who are both of Auckland.
No doubt, a winery dinner befitting the occasion will follow after they cross the finish line in what can probably pass off as a good excuse for a gathering, almost in the mould of a Christmas-type reunion halfway into the year.
Parnell is no stranger to walking. She regularly ventures out from her Greenmeadow home to the well-trodden nearby Park Island walkways.
"I don't think I've been doing 10ks but I won't have any troubles with 10ks. It's not that far."
Her preoccupation is to tame the picturesque 10km at a brisk pace while enjoying the last stretch of the 42.2km course from Gimblett Gravels to the Sileni Estates.
"I want to do it in a reasonable time and pace, come what that might be," she says.
Parnell is considering running the next time over the same distance if everything goes well today.
She has a sporty background, having ridden horses, played netball and ploughed up the fairways of golf courses before dutifully replacing her divots in 30 years as a member of Maraenui Golf Club.
The amateur, who got down to an 11 handicap, represented her club in the Pennants competition.
She suspects her grandfather, the late William Guy Harding, of Wellington, broke a middle-distance record and held it for almost a year although her 95-year-old mother, Judy Rogers, of Taradale, has confirmed that with a modicum of certainty.
"I was never that good or keen in running. I didn't inherit his genes," says Parnell but agrees it's never too late to embark on a journey of self-discovery and hasn't, in hindsight, gauged her worth as a runner because she hasn't really put herself through the spin-dry cycle as such.
EVENT SCHEDULE
8am-5pm: Info desk open, Sileni Estates Winery.
6am-7.15am: Shuttle bus departure times to start lines vary with event.
7.45am: AIA 10km start, Gimblett Gravels Wine District.
8am: NZ Sotheby's half-marathon start, Pakowhai Regional Park.
8.15am: Air New Zealand full-marathon start, 350 Marine Pde, between Edwardes and Sale Sts, Napier.
12pm: Kids' run start, Sileni Estates Winery.
12:30pm: Prizegiving, kids' run, 10km and half-marathon, Sileni Estates Winery.
8am-5pm: Post-race festival, Sileni Estates Winery.
2.30pm: Prizegiving full marathon, Sileni Estates Winery.
10am-4pm: Post-race shuttle bus departure times. Sileni Estates Winery to Marine Pde, Napier via 10km and half-marathon start lines; and to Hastings and Havelock North.
