Cool running

Wang Xiaogang, a Beijing running coach, poses with his race medals. Provided to China Daily

Du, of ZX-Tour Co, says one of the reasons for the explosion in travel is that people who have run the relatively new marathons in China are looking for a taste of better-run races abroad, as well as higher athletic levels.

But in addition to that, what could be cooler than posting a selfie as you cross the finish line in Paris, Boston or Berlin, or wrap yourself in the national flag like an Olympian?

"It's not a decisive factor, but posting pictures on Chinese social media while taking part in running events in exotic locations is seen as a trendy thing for some runners," Du says.

Xie, from Shanghai, says running now dominates her life, socially and professionally. "Marathons are also a way to have a social life. I have met many friends running. It's why we get together," says the entrepreneur, who quit running a real estate company to start Save U Sports Development Co, which helps clients with equipment and advice.

Some Chinese runners are also combining marathons, social media and social responsibility.

Li Xibei, 30, an information technology worker from Central China who lives in New York City, raised funds to provide cleaner air to families in his homeland by running the North Pole Marathon this month.