Despite aiming to run 25 miles (40.2km) a day, Mr Matthews, nicknamed The Milky Runner on social media due to his complexion, said running had “never been my specialty”.
“In fact, I always hated running. But it was something that I could pick up and do without having to learn more skills,” he said.
“I believe it is more about willpower to get through it.”
He estimated it would take six to seven hours to run each marathon, with rest days only taken when essential.
The challenge, which begins in Brighton on 1 September, is self-funded, with Mr Matthews hoping to fund the challenge through a GoFundMe page.