Marvelly's goal is to raise at least $30,000 through his marathon effort and he is already a third of the way there.
"It's not about me, I'm just the vehicle. A lot of friends and colleagues have got behind this, not necessarily because it's me but because it's a really good cause. Our vision with this trust was for Rotorua Hospice to always be looked after.
"They offer so much in those last few weeks or months or days [of a person's life] for families who really need it. It's for everyone. It doesn't matter what you are or who you are, they're there for you and that's the neat thing about it. There's a real need for that."
He has been training for the last nine months.
"It started with a bit of a run around the block. My wife said 'I'm sick of you talking about it, why don't you do something about it'. So that's when i got a bit more serious and joined the Lake City Athletic Club's Rotorua Marathon Clinic."
Each year, participants in the running clinic are put into packs with others doing the same distance - 10km, half marathon or full marathon - with a similar expected finishing time to prepare for the Rotorua Marathon event.
"It's been wonderful, they're really good and really professional. I just love the way all the people doing it have bonded as well, it's a lot of really neat people from all different walks of life and we all have that common goal.
"It is a journey and we all share in each others' successes - every run is another accomplishment. It's the best thing I could've done because if I'd been doing it myself I would've stopped. When you've got 10 or so other people doing it you can't just pull out."
His legs aren't what they were when he first did the Rotorua Marathon 28 years ago but Marvelly has stuck to his training plan and is well on track to complete the 42.2km run.
"I don't mind admitting it is hard, obviously the older you get you have to go that much harder. Your body doesn't respond as quickly as when you're younger.
"In saying that, I strongly recommend it to anyone that wants to do something. It does get you out especially with the Lake City clinic - it's not just for the marathon. They've got the half marathon, the 10km, the walks and I love seeing the families there with the children running.
"I have [enjoyed the experience more than expected]. I've enjoyed the challenge. It's a challenge but it's a really organised challenge as far as planning is concerned. Every week there is a different run and it's a different run for a different reason."
Marvelly says any donation to the cause, big or small, will go along way. Anyone interested in contributing can contact him at brett@marvelly.co.nz
