There is the Colson Patisserie, the mayor’s favorite morning stop; the S & S Cleaners; the nearby Brooklyn Public Library branch where Mr. de Blasio votes; the Little Purity Diner; and Bar Toto, where he has held meetings and made fund-raising calls.

The uniqueness of the mayor’s routine has been noted since his early days in office, before he and his family moved to Gracie Mansion from their Park Slope home. But close observation by a reporter for The New York Times, who is a fellow member of the Y.M.C.A., reveals it to be more rigid, lengthy and leisurely than previously known.

During a recent week, Mr. de Blasio did not miss a single workout — hitting the gym each and every weekday, usually leaving the mansion around 8 a.m. or a bit later.

He texts and emails on his phone. He stretches. He reads sheets of paper and watches television news. He once appeared to be reviewing a speech or a policy brief.

No City Hall staff members came to speak with him nor did any other friends or associates. His wife, Chirlane McCray, accompanied him to the gym on two days, though they mostly worked out separately.