Daily hunger sensation monitoring as a tool for investigating human circadian synchronization

This study investigates within-day hunger sensation (HS) variability in Clinically Healthy Subjects Adapted to Living in Antarctica (CHSALA), as compared to their coeval subjects living in their mother country. The aim is to detect how the orectic stimulus behaves in those environmental conditions and occupational schemes, in order to investigate the individual synchronization to sleep-wake alternation and meal time schedule. HS was estimated via a self-rating score of its intensity on a Visual Analog Scale, repeating the subjective perception every 30 min, unless sleeping. The individual HS time-qualified scores (orexigram) were analyzed according to conventional and chronobiological procedures. The orexigrams of the CHSALA were seen to show a more cadenced intermittence during the diurnal part of the day, strictly related to the meal timing, and a preserved circadian rhythm as well. In addition, these orexigrams were resolved in a spectrum of harmonic components which indicated a subsidiary number of ultradian formants. These findings are convincing evidence that the individual orexigram may be used to investigate whether or not a single subject is synchronized to sleep-wake cycle, meal time schedule and socio-occupational routines, instead of using more complex and expensive techniques, involving automated equipments and biohumoral assays.