Joanna Coles, a former editor of Cosmopolitan who was appointed one of the highest-ranking executives at Hearst Magazines in 2016, has resigned from the company. Her decision to leave ends her 12-year stint at the publisher, which she joined in 2006 as the top editor of Marie Claire.

 Coles, who is known for using a treadmill desk at work, posted a short video on social media on Monday. “Have you any idea of the miles I have walked on this treadmill desk through the peaks and the valleys of Marie Claire, Cosmopolitan and as Hearst’s first chief content officer?” she said while walking on her trusty machine. “But my route is being recalculated. It’s time for a new adventure.”The selection of Mr. Young,  to take control of Hearst’s magazines signaled the company’s intention to move more deeply into digital media. He was in charge of the company’s online efforts before he succeeded David Carey, as the president of the magazine division.

 Coles, who was born in Yorkshire, England, was the New York bureau chief of The Guardian and a columnist for The Times of London before going into the magazine business. She distinguished herself at two Hearst titles by expanding the role of magazine editor into a position that embraced multimedia.

While at Marie Claire,  Coles became partners with the reality show “Project Runway All Stars” and served as an on-air mentor to its contestants. Later, she made Cosmopolitan a popular destination on the Snapchat Discover platform, attracting three million daily visitors.Her television work has continued.  Coles, is a regular pundit on cable television and has worked on both sides of the camera for an E! channel reality show, “So Cosmo.” She is also an executive producer of “The Bold Type,” a series set at a women’s magazine that airs on the ABC-owned cable network Freeform, with the actress Melora Hardin playing a character modeled after  Coles.

She joined the board of Snap, the maker of Snapchat, in 2015, which paid her $110,866 in cash and stock in 2016. She signed a new contract at the beginning of last year and now receives a package worth $896,179 that pays out over a three-year period, according to security filings. Earlier this summer she was made an Officer of the Order of the British Empire for her contributions to journalism and the media business.