Journal ArticleDOI
A Mathematical Model of the Human Circadian System and Its Application to Jet Lag
TLDR
A mathematical model of the circadian system is described that is appropriate for application to jet lag and estimates were obtained for the intrinsic period of the oscillator, its stiffness, and the external force.Abstract:
A mathematical model of the circadian system is described that is appropriate for application to jet lag. The core of the model is a van der Pol equation with an external force. Approximate solutions of this equation in which the external force is composed of a constant and an oscillating term are investigated. They lead to analytical expressions for the amplitude and period of free-running rhythms and for the frequency limits of the entrainment region. The free-running period increases quadratically with stiffness. Both period and amplitude depend on the value of the constant external force. The width of the range of entrainment is mostly determined by the external force, whereas the relative position of this range follows the intrinsic period of the oscillator. Experiments with forced and spontaneous internal desynchronization were evaluated using these analytical expressions, and estimates were obtained for the intrinsic period of the oscillator, its stiffness, and the external force. A knowledge of th...read more
Citations
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Journal ArticleDOI
Stability, Precision, and Near-24-Hour Period of the Human Circadian Pacemaker
Charles A. Czeisler,Jeanne F. Duffy,Theresa L. Shanahan,Emery N. Brown,Jude F. Mitchell,D. W. Rimmer,Joseph M. Ronda,Edward J. Silva,James S. Allan,Jonathan S. Emens,Derk-Jan Dijk,Richard E. Kronauer +11 more
TL;DR: In this article, the intrinsic period of the human circadian pacemaker averages 24.18 hours in both age groups, with a tight distribution consistent with other species, with important implications for understanding the pathophysiology of disrupted sleep in older people.
Journal ArticleDOI
Optimal schedules of light exposure for rapidly correcting circadian misalignment.
Kirill Serkh,Daniel B. Forger +1 more
TL;DR: A new methodology to find mathematically optimal schedules of light exposure and avoidance for rapidly re-entraining the human circadian system is developed, which appears to be significantly more robust to both noise in light and to inter-individual variations in endogenous circadian period than other proposed schedules.
Journal ArticleDOI
Resynchronization of circadian oscillators and the east-west asymmetry of jet-lag
TL;DR: By examining the phase space dynamics of the forced Kuramoto model, this work studies the mechanism leading to the difference typically experienced in the severity of jet-lag resulting from eastward and westward travel.
Field-based validations of a work-related fatigue model based on hours of work
Adam Fletcher,Drew Dawson +1 more
TL;DR: Work-related fatigue scores were calculated and compared to alertness and performance measures in this paper, showing that there was a stronger relationship between predicted fatigue and self-rated alertness than between fatigue and performance.
Journal ArticleDOI
Sleepiness of civil airline pilots during two consecutive night flights of extended duration.
TL;DR: It is concluded that improvements such as the introduction of a nap schedule should be considered to alleviate spontaneous sleepiness in the cockpit.
References
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Journal ArticleDOI
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