Philip Rogerson, who became chair of Central YMCA in August, says a personal appreciation of the charity's work sparked his interest in the role.
"My daughter started suffering from ME, a chronic fatigue condition, just as she was taking her final exams to go to university," he says. "She was incapacitated for two years. The thing that really got her out of it, and helped her recovery, was exercise."
The health charity, which was the first YMCA to be established in 1844, promotes activity and exercise through education, training and its own touring theatre company.
"I've seen what exercise can do and how important it can be, so to be working with a charity that supports young people and health seemed very appropriate," says Rogerson.
"If you're honest with yourself, you know when the time has come to step down," he says. "You stop and think, would somebody with fresh eyes contribute more to this? At Changing Faces, that is what I thought. I had been there for 15 years, so it was time."
Rogerson says one thing he has learned about charity governance is that a chair should build up a close and supportive relationship with the chief executive.
"You should be a strong right arm for the chief executive," he says. "If you have a good chief executive, and you agree with his or her direction, you can be a good source of support.
"For a chair to come in on an occasional basis, look at the charity's work and try to change things strikes me as inappropriate."
Rogerson says the charity, which is based on Tottenham Court Road in central London, is not to be confused with the YMCA's central umbrella body, YMCA England. Central YMCA does not run a hostel, but it does run courses in IT and sculpture and a theatrical touring company, as well as sports and recreational facilities for its 6,000 members.
He says his YMCA role differs from his other work as a paid chair of the generator rental firm Aggreko, the distribution firm Bunzl and the construction and facilities management firm Carillion.
"I've noticed that, on the whole, charity trustees come from much more diverse backgrounds than members of company boards," he says. "It means you get a lot of different points of view, and consequently it can be more difficult to reach a decision."
Rogerson says he has been impressed by the levels of commitment among charity trustees. "In my experience, trustees have a huge reservoir of goodwill towards the activities of their charity," he says. "If there's an idea that is seen as being a good thing to do, then the board will move heaven and earth to make it happen."
He says it is too soon to know whether he will attempt to make any major changes at the charity, adding that his first priority is to meet the staff and learn more about its work.
"I certainly think it is the chair's role to challenge the charity about where it will be in the future, and to ask whether it is happy to stay steady with the work it is doing or should expand," he says. "But I'm not at the stage of doing that just yet."