Every morning this week at 8am Sanders has set out from Hobsonville School, his 42km route taking him through Massey and Henderson before returning to the school.
Pictures from Sanders' first marathon on Monday showed a broad grin, and he was still chipper on Tuesday despite "horrible weather".
But on Wednesday, Sanders started his third marathon "feeling like failure was on the horizon", according to his Instagram.
"Had a little fella pull over and donate while running, that's what it is all about. Community helping community."
Thursday was "hump day", he wrote. "Legs feeling okay, feet are cooked."
On Friday, he wrote, "Fatigue hit like a truck", though he was blown away by the love and support of the community.
By Saturday - marathon number six - Sanders was still smiling but posted to Instagram that he was "beyond ruined".
"It just showed me how far you can push the human body when the purpose is bigger than yourself."
Today, Sanders told the Herald it was "people power" that helped him finish his seventh marathon at 12.50pm - about an hour and 15 minutes faster than previous days.
"There were heaps of people around - they dragged me through," he said. "I knew I'd finish if I got to today."
He now plans to "chill" for a couple of days before heading to the physio on Friday - though he thinks his body has held up despite pounding the pavements for 295.4km in a week.
"I'm doing a hike over New Year's so hopefully everything's sweet by then."
