If you are physically capable I would absolutely get a bicycle! I deal with my hypomania and depressive symptoms by going out and exerting myself, rain or shine. Sometimes the physically toughest rides offer the most mental benefit! And I'm more of a pianist than an athlete. It has helped and I would say MUCH cheaper than gym memberships, allowing me the option to commute to work, volunteering, or even parties while getting some blood flowing.

Just my opinion, but I'm a huge proponent to exercise for mental stability.

JA