One-year trial of 12-hour shifts in a non-intensive care unit and an intensive care unit in a public hospital: a qualitative study of 24 nurses' experiences.

The results indicate that individual preference for working 12-hour shifts is a function of own health situation, family situation, work load tolerance, degree of sleep problems, personality and other factors. If the goal is to recruit and retain nurses, nurses should be free to choose to work 12-hour shifts.