The problem is that with all they vast wasted space, the burbs rarely have any room for outdoor exercise. Roads have no sidewalks, so walking or bicycling can be very dangerous, especially that some SUV-driving assholes try to intimidate bikers and pedestrians by driving very close.
There are almost no green spaces - everything is private property off limits to the public.
There are more public parks and walkways in Baltimore (or New York for that matter) than in suburban Harrisburg where my wife lives.
The only way to exercise it to either join an aerobic club or buy exercise machines and place them in you basement - which fits very well the overarching goal of suburbs: maximize consumption and spending.
Wojtek