He has pushed his body to the limit, running 10 mara- thons in 10 days to raise funds for the homeless.
However, exhausted Dubliner Mark Conlon won't be taking time off to recover, saying he needs to start training for his "biggest ever challenge".
The big-hearted former soldier was given a hero's welcome yesterday afternoon when he finished his 10th marathon in as many days in Sallins, Co Kildare, raising thousands for the charity Inner City Helping Homeless.
Super-fit Mark (36) said he will be back in training tomorrow for another charity event "bigger than anything I've ever done before".
The Clondalkin man's past feats include running a record-breaking 33 marathons in 33 days and another punishing challenge in which he covered 50km a day on foot for 22 days.
"My next charity challenge is going to be the biggest," said Mark, a security officer on the Luas.
"I'm not in a position just yet to announce what it is, but it will be on a larger scale than anything I've done in the past and I'll need to be fitter than I've ever been if I'm to be successful."
Marathon man Mark has previously revealed an unlikely secret behind his epic achievements - calorie- laden fast food.
"I eat healthily enough but also enjoy pizza and going down to the chipper," he said.
"This works for me when I'm racing because you burn the bad fats off.
"I think the way I eat helps my body recover. I've also never collapsed during a race and put that down to my diet. So certainly the diet I have works best for me."
Reflecting on his just- completed 10-marathon challenge, he added: "It's been tough and I think that's partly because my body has still not fully recovered from last year, when I did the 33 marathons.
"My right knee has certainly felt it over the past 10 days, but I paced myself and never felt like I wouldn't finish any of the distances.
"I respect every single marathon I do and never take anything for granted.
"And when you think of the homeless people out on the streets, that's all the motivation I need."
For details on how to donate, check out 10 Marathons in 10 Days for Inner City Helping Homeless on Facebook.