Burnout among shiftwork personnel such as nurses are prevalent, and the evidence suggests an increasing trend of nurse drop out in complex healthcare settings. While nurses' acute and chronic fatigue have been studied, current models of fatigue do not capture the pre-chronic phase we refer to as "aggregate fatigue" -the buildup of fatigue and stress exceeding the capacity for physiological and cognitive recovery processes. Understanding aggregate fatigue requires a holistic understanding of a wide range of contributors including sleep, work, non-work-related stress, cognitive load and other psychosocial factors. This paper proposes an integrated model of fatigue in hospital nursing and presents a comparison to the common models of fatigue and burnout. We use a narrative review of literature to ground this multi-attribute model of aggregate fatigue which may shed light on future methods to identify and mitigate fatigue build-up contributing to burnout.