How is endogenous melatonin involved in circadian rhythms?
The scope of this question was limited to an analysis of how endogenous melatonin is involved in the temperature rhythm. The analysis of evidence relevant to this question was approached in a similar manner as for the question relating to the link between endogenous melatonin and the sleep cycle, in that we addressed the link between endogenous melatonin and the temperature rhythm. A study was considered relevant to this question of the review if it involved an intervention that altered endogenous melatonin levels or the temperature rhythm, such as a manipulation of light/dark exposure or body temperature, and it examined either melatonin levels in blood, urine, saliva or CSF or an aspect of the temperature rhythm, depending on which of these variables was manipulated. Thus, if the study intervention was designed to manipulate endogenous melatonin, then it was necessary that the study examine the effect of this manipulation on an aspect of the temperature rhythm, and vice-versa. These
