This paper is the closest I have found that touches on the particular night shift work area that I am interested in. It is a given that normal body function cannot resist the effects of circadian rhythms and the chemicals excreted during the nadir.  It is also a given that adrenalin is excreted in response to heightened alertness, especially in a policing environment. My unanswered question is what the effects of these competing cocktail of chemicals are. Adrenalin-v-Renin, melatonin and cortisol? Are there any known side effects and subsequent health issues. My 33 years experience as a police officer and shift work supervisor indicates that the effects are varied and often impact on the quality and accuracy of post incident process quality. Recollection of events for evidentiary purposes and compounding factors should a similar event occur on the next or subsequent shifts. Interested in participating in any discussion groups re this subject.