strange as it may seem, some gyms require that you have both. That is at least true for the place where I teach some classes. The rationale is simple: a college degree, as important as it is, loses its value over time because there is no requirement for continued education. All good certification programs mandate a certain number of continued education credits over a 2 year period to stay current.
You may notice, though, that some advanced certifications, such as ACE AHFS, require a college degree as a pre-requisite.