Posted by Ueli on October 27, 2001 at 20:02:44:
The circadian cycle regulates the the daily pattern of our life: sleep, hunger, digestion and even crapping.
Circadian means 'about a day': for most people the free-running cycle length is about 25 - 26 hours, but for some it's shorter. This free-running cycle length can only be observed when an individual is in an environment that lacks every cue to the usual daily routine: constant illumination, no watch nor TV, eating when hungry, etc.
In our ordinary daily life, the circadian cycle is synchronized to 24 hours by a myriad of external cues. However, different natural cycle lengths give raise to phase shifts in secondary cycles: We all know people who regularly go to bed simply because they are tired: their Melatonin production sets in early. On the other hand, in people who go to bed in view of the time they have to get up, the Melatonin production starts later.
For clusterheads:
Investigations have shown that a clusterhead, in or out of a CH period, has a completely flat Melatonin level, throughout the day.
For some clusterheads taking Melatonin before bedtime, and so mimicking the natural cycling of its concentration, can be beneficial on the nightly CH attacks.