But one runner competing in her first ever marathon had more than a gruelling 42Km to celebrate once she was done - as finished with not just a medal but a ring too.
Nurse Kaitlyn Curran was nearing the 26Km mark of the New York City Marathon when her boyfriend Dennis Galvin hopped over the barrier to surprise her by getting down on one knee and popping 'the question'.
A video shot by Galvin's cousin Kathleen Figueroa captured the romantic moment in its entirety, and has garnered quite a few comments on Twitter.
"People in the race were slowing down to take pictures. It was indescribable just to be there and see it all was amazing," Kathleen Figueroa told CBS News, adding "She cried a little bit, said yes, hugged him and then said 'OK, I have to go finish my race."
Many Twitter users however don't seem too impressed that the groom-to-be interrupted his girlfriend's race with his romantic gesture, with some commenting that he 'messed up her time' and questioning why he didn't wait until she reached the finish line.
"He couldn't propose to her at the finish line?" pondered Twitter user Susie McDonell.
"AND he didn't even take her sweatshirt that she clearly didn't want or need! I'd have given the ring back at the finish line," added Sarah Spelt.
"If he really loved her, he would've waited until after the race, given her a massage, taken her to a nice dinner, left her alone all night so she could have a nice long rest, woke her up the next morning with homemade waffles and strawberries, then asked her to marry him. Geez"
One woman even commented to say she had been proposed to at the NYC marathon - but added that if her fiancé hadn't waited until the finish line to pop the question, she would have said no.
Galvin's cousin however explained that he wanted to pop the question at the first Manhattan stop of the race, which is located at Mile 16 at the Queensboro Bridge.
The happy couple celebrated with friends and family when the bride-to-be finished the run - just over 16Km later.