Northfield Senior Center offers programs for active adults, ages 50 - 105 The Northfield Senior Center, designed by forward-thinking seniors, is housed in a new facility that offers a warm water exercise pool, fitness work-out room, fitness studio, card room, art gallery, dining center, computer center and classrooms. Over 45 exercise classes are offered each week. By relying on seniors to design for seniors, the Center has turned the stereotype of old age upside down. The most poignant testimony to the vitality and opportunities that are available are the words of noe new member, "At last, I've turned 50 so I can join the Senior Center!"