UPPER EAST SIDE, NY — Mile High Run Club, an Upper East Side boutique cardio studio, is closing its doors next month, the studio said.

The studio, located at 1251 Lexington Ave. near East 85th Street, will host its last day of treadmill classes on April 12, according to an email sent to customers shared with Patch.

“So much happened inside these walls,” the message read. “Runners trained for their first 5K, or their tenth marathon, and some even logged their very first miles here.”

The cardio studio, which features treadmill-based running classes with pop music and flashing lights, will continue classes at its West 25th Street location.

“This community is something we’ve been proud to build together,” the group wrote.

It’s not yet known what will take its place, but it was listed for rent on Wednesday.

Know of a business opening or closing in Manhattan? Email Miranda.Levingston@Patch.com.