Adapting to phase shifts, I. An experimental model for jet lag and shift work.
An experimental model was developed to measure various behavioral and physiological parameters in a laboratory paradigm mimicking phase shifts that could occur in time-zone transitions and shift work rotas. Volunteers were exposed to 9-h pulses of bright light (1,200 lx) as follows: day (D)1: 1800-0300 h, D2: 2100-0600 h, and D3, 4, 5: 2400-0900 h, each period followed by 8 h darkness. Immediately following the last treatment, subjects resumed their baseline sleep/wake schedule in a normal environment, thus experiencing a rapid 9-h advance phase shift of local time cues. During the gradual delay shift, a progressive delay shift in the rhythms of urinary 6-sulphatoxymelatonin (aMT6s), temperature and alertness was evident (maximum shift: 9.13 +/- 0.83 h, 9.09 +/- 1.06, and 10.62 +/- 0.96 h, mean +/- SD, respectively). There were no important detrimental effects on behavioral variables. After the rapid 9-h phase advance, sleep patterns, temperature amplitude, aMT6s acrophase, alertness, and performance took at least 5 days to reestablish normal baseline patterns. This model provides an effective and inexpensive model to study adaptation strategies in real life.
Deacon
S
S
Chronobiology Laboratory, School of Biological Sciences, University of Surrey, Guildford, UK.
Arendt
J
J
D000328:Adult; D000339:Affect / Q000502:physiology; D001143:Arousal / Q000502:physiology; D001831:Body Temperature / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000031:analogs & derivatives / Q000652:urine; D008960:Models, Psychological; D011597:Psychomotor Performance / Q000502:physiology; D012890:Sleep / Q000502:physiology; D014195:Travel; D014940:Work Schedule Tolerance
C054513:6-sulfatoxymelatonin; D008550:Melatonin