Far from melatonin's time horizon: Halting steps from pediatric ultradians toward a chronome

To resolve chronomes (portmanteau'd telescoped from chronos = time and nomos = rule), we must abandon the current general position with respect to physiological variation in the normal range, a barrier which exists only in the mind of current homeostatic science. Once we realize that it is possible to walk through walls, because the walls are only there by our era's deeply rooted conventions, we arrive at time structures, chronomes. Ultradian changes with periods of 3.4 and 1.5 hours, putatively associated with rapid eye movement sleep cycles, characterize nocturnal melatonin in boys and girls. These patterns were found in 8 girls and 8 boys, 8.7-16.8 years of age, classified by Tanner pubertal stage. Between 19:00 and 07:00, each provided blood samples at 30-min intervals for melatonin RIA. Associations with gender, body mass index, and chronological and pubertal age, determined by multiple linear regression and ANOVA, reveal that the area under the curve of 12-hour melatonin concentrations was affected by pubertal rather than chronological age, an effect to which data collected during darkness contributed the most. An about 8-hour component was also statistically significant in a least squares spectrum, with frequencies in the range of 1 to 20 cycles per day. Melatonin circaoctohorans are also found in pigs and in human adults. Infradian components assessed transversely include a half-yearly variation that may be geomagnetic latitude- and circadecadal stage-dependent, notably since nocturnal melatonin may be depressed in association with magnetic storms of sufficient severity. Notably infradians accounting for intermodulations remain to be mapped in children, in order to build a time horizon by an ever broader melatonin chronome of use in preserving health and treating disease.