Most people don’t participate in a marathon to win.

Their motivations vary greatly, actually.

“I think there are many different runners out there in which you’ll find different motivations from each of them,” said Lynette Craft, an expert in exercise science and an assistant professor of preventive medicine at Northwestern University.

So what does motivate a person to run a marathon? Here are a few common factors:

1. People are motivated by the health outcomes, so they’re doing it because they want to be healthy. A few of the benefits range from burning calories, improving conditioning and reducing the risk of heart attacks.

2. People are motivated to engage in an exercise or a weight-loss program.

“I think you have people who train for something that keeps them motivated on the day-to-day,” said Craft. “You’ll have people who maybe aren’t necessarily athletes or haven’t participated in sports previously, who are out there for the first time doing a competitive event.”

3. People are motivated for the appearance-related outcomes that happens from long-term physical activity. Running can slow the aging process, for instance, as well as enhance the glow of the face by promoting human growth hormone which helps individuals stay young.

4. People are motivated by the camaraderie that occurs when they’re training.

“In marathon training, there are running groups and running clubs where you’re not necessarily always just running by yourself,” Craft noted. “There’s a social aspect. Those are people that are really motivated by the fact that there are other people that are going to be there doing it with them, so it provides a level of accountability because they’ll notice if you don’t show up to a running group.”

5. People are motivated just to see how far they can push themselves. Marathon running is an extreme event, so some people want to see if they can physically and mentally do it.

“A lot of it is the challenge of it and the sense of accomplishment,” said Dr. Dan Kirschenbaum, director of the Center for Behavioral Medicine and Sport Psychology in Chicago. “It’s one of those feats that other people admire and it’s not many things people can do.”