In July, a Penkridge window cleaner will begin the mammoth challenge of running 90 marathons in 90 consecutive days, a total of 2,340 miles. Or put it another way, more or less what the average motorist will drive in their car over that period.
And that's not all. There will be no respite during the hours in between his marathon runs. The 31-year-old, will be carrying on with his window cleaning rounds throughout the gruelling three-month period. Although he will be allowing himself the luxury of travelling to jobs in his van.
Mark, who grew up on Shrewsbury's Telford Estate and attended the town's Belvedere School, has set himself a target of raising £90,000 for the Tommy's pregnancy charity and the Katharine House hospice in Stafford. And he is so committed that he will even carry on his challenge when he goes on holiday to Cornwall at the end of July.
And if that is not enough, he has thrown down the gauntlet to his sponsors, saying that he will also run from his home to London in three days at the end of his challenge in October if he manages to raise at least £30,000 for his chosen charities.
The run will well and truly put Mark in the history books. At the moment, the world record for running the most marathons in consecutive days stands at 52, so if he is successfully at pulling off his feat he will annihilate it.
But he is hardly lacking in confidence.
"I'm really looking forward to it," says Mark, who is a qualified fitness instructor.
"The important thing is to have a good recovery rate. At the moment I have been out running every day. This week I will run 21 miles, 13 miles, eight miles and a 28-mile run, followed by a lot of core training after."
As you might expect, there is a powerful driving force motivating Mark's efforts, and it is his wife Tammy who has endured six miscarriages and has found the support from the Tommy's charity a huge help.
She says: "I had my first miscarriage in January, 2007, at Walsall Manor Hospital, I lost a little boy called Harley, that was very traumatic, it was very emotional."
Tammy's second miscarriage came in June 2011, just before the couple's wedding the following month. The couple suffered further heartache in 2012, when Tammy miscarried at New Cross Hospital in Wolverhampton, and then again in 2013 and twice in 2014.
"Many of the hospital staff just didn't know what to say," says Tammy, who is an English teacher at South Wolverhampton and Bilston Academy.
Happily, Tammy is expecting once more, and is now receiving support from Tommy's which helps expectant mothers through the different stages of pregnancy.
"I found out about Tommy's while I was reading an article about a lady who had problems feeding her baby, and she found them quite supportive, they got her the right treatment," says Tammy.
"A lot of the problem is not being able to speak about the issues, Tommy's take a holistic approach.
"They are able to offer advice about the different kinds of treatment that are out there.
"People don't understand unless they have been through it, there is the excitement that comes before, and then the way that all your dreams are dashed.
"People don't like talking about it."
Mark adds: "We both want to raise awareness in regards to more support being there, as at the time there was none."
Mark's runs will see him pounding the streets of Telford, Ironbridge, Bridgnorth and Newport, as well as nearby towns, villages and cities such as Wolverhampton, Walsall, Wombourne and Stafford – where he will also stop off for a 12-hour session on an exercise bike.
"I'm hoping that other people will join me for the exercise bike ride in Market Square," he says.
"I'm hoping to do it for the full 12 hours, but I don't expect others to do that, they can swap over with each other, and do whatever they feel they can to raise a bit of money."
"My 88th run will be in Shrewsbury because that is my home town, and I will then finish in Balloch in Scotland because that is where we got married."
Not that it will be the end of his fundraising by any means. Once he has sealed his place in the record books – he has had to spend several hours mapping out his routes to satisfy the stringent requirements of the Guinness Book of Records – he plans to follow it up by running from Land's End to John O'Groats next year.
"Ninety marathons in 90 days will be great training for next year," he says.
At the moment, he is focused on meeting his ambitious fundraising target, and drumming up support from companies which will pay to have their names on his shirt.
"At the moment I'm on £610, which is not where I want to be, but I'm confident that I can do it," he says.
"I love running, it takes away the everyday stress of life and makes you forget about everything, it's a bit like going to sleep."
It's just as well he enjoys running. He has got a fair bit of it planned over the coming months.
*To support Mark see the website www.virginmoneygiving.com/team/9090 or his Facebook page www.facebook.com/pages/90-marathons-in-90-days.