Interview questions

I have an interview for a position with another healthcare system. I decided to seek employment elsewhere due to the large amount of call time we are required to take. I was wondering if those of you who are responsible for interviewing applicants frown on this as a reason for leaving a position. It is the only factor that is bad enough to make me look for another job. I like my job, the work, and my manager. I would love to keep this job, but the call will not change and it is excessive (up to 36 hrs. every pay period).

Should I be honest or just say the job isn't a good fit? What if they ask why I have decided it isn't a good fit after almost 4 years? Should I mention that the call makes it difficult to complete my classwork by the due dates (I am going for a higher degree). I don't want to seem so closed off that they feel I am avoiding the questions, but I don't want to say too much either.
Four years is a long time to stay in today's market. You could simply say you are looking for new experiences and challenges.

I've been there...I hate call. As long as the job you are applying for doesn't have a call requirement, you should be fine. When I was in the same boat, I said that the call requirement was too stressful for my family (phone ringing at all hours). The HR person said: "wow, that sounds awful".I don't think you need to dwell on it but having to take call is something most people can understand as a negative.

Thanks for the responses. I am excited about the opportunity and want to prepare as much as possible. Apparently there are alot of applicants who are interviewing and I want to do my best to increase my chances.