But accountancy student Matt Waddingham, 31, had more reason than most to be nervous about the race – after hatching a plan to propose to his partner Sarah at the finish line.
Once the Scunthorpe couple completed the race together after an hour and a half, their children James, six, and Ava, two, presented themselves with T-shirts which read: “Mummy will you marry Daddy?”
Mr Waddingham said: “Just three weeks ago is when I started to think it might be possible.
“It’s Sarah’s birthday today so I wanted to make it special.
“When she realised what the T-shirts said she started crying.
“She said yes, thank God!”
Sarah, 36, said: “It was a massive surprise. I didn’t know what to think.”
But she added that Matthew chose the “perfect” occasion to pop the question.
The pair are yet to set a date for the wedding, which will be their second following a separation.
Mr Waddingham thanked Age UK and his step-daughter Courtney Stanley for helping to make the proposal happen.