title: Modeling interactions between photic and nonphotic entrainment mechanisms in transmeridian flights.
abstract: In transmeridian flights, photic and nonphotic entrainment mechanisms are expected to interact dynamically in the human circadian system. In order to simulate the reentrainment process of the circadian rhythms, the photic entrainment mechanism was introduced to our previous model, which consisted of three coupled oscillators. Regardless of flight direction, a large time difference beyond 10 h tended to induce the antidromic reentrainment. The partition between the oscillators resulted for the eastward flight over a 10-h or longer time difference and the westward over 6 h or longer. The simulated reentrainment processes almost coincided with empirical knowledge. Simulated effects of physical exercise showed that some antidromic reentrainments were switched to the orthodromic ones for the eastward flight and most of the partitions between the oscillators were prevented in the westward flight. These results are due to an augmentation of the entrainment pressure of the rest-activity cycle on the oscillators. The mechanisms underlying these various reentrainment patterns were explained based on the photic response, the interactions between the oscillators, and their adaptive modification. The simulation results suggest that an appropriate selection of departure time and physical exercise could ease the jet lag caused by transmeridian flight.
authors.affiliation: Graduate School of Information Sciences, Tohoku University, Aobayama 09, 980-8579, Sendai, Japan. nakao@ecei.tohoku.ac.jp
authors.forename: Mitsuyuki
authors.initials: M
authors.lastname: Nakao
authors.forename: Keisuke
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Honma
authors.forename: Satoko
authors.initials: S
authors.lastname: Hashimoto
authors.forename: Sato
authors.initials: S
authors.lastname: Honma
authors.forename: Norihiro
authors.initials: N
authors.lastname: Katayama
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Yamamoto
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000337:Aerospace Medicine; D001683:Biological Clocks / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D020179:Jet Lag Syndrome / Q000503:physiopathology* / Q000628:therapy; D008027:Light; D008959:Models, Neurological; D010809:Physical Fitness / Q000502:physiology