Modelling of the shift work with various rapids of rotations
E.S. Mchedlova 
and A.D. Trubetskov 
Saratov State University, Russia;
Saratov State Medical University, Russia
One of the main problems in studying the influence of the work in different shifts on the man health is the complexity in making comparison between various schedules. Until now the method of the quantitative estimation of the consequence of the work in different shifts on the circadian rhythms doesn't exist.
To solve this problem the model of the circadian man rhythms system and its interaction with external pacemakers was invented. The basic of this model are the oscillators with approximate period, connected between themselves by the type of the network. They are under the external influence that is modelling by the periodic function with approximate period. This external rhythm may be displaced by the phase in the given regimen according to the modelling schedules of the work in various shifts. The basic of the analysis of the model's synchronous condition break with changing the external rhythm phase the index, that characterizes the desynchronous was invented.
By means of the model in numerical experiment the dependence of this index value on the shift rotation rate by the graph constructed on the work in 2 or 3 shifts has been studied. The desynchronisation value of the circadian rhythms by work in 2-shifts appeared to be on the average smaller than that by work in 3-shifts. While working in 2 shifts the influence of high rapid rotation (after 2 - 3 days) on the biological rhythms is by far the largest. Optima are regimens with rotation after 7 - 8 days. By the work in 3 shifts regimen index, that characterizes desynchronization value is moderately lower at rapid rotation. Beginning with 5-days protraction of every work-time period the rotation speed doesn't influence effectively enough the circadian system.
These data agreed in general with the results of the clinical observation of the labourers, working in different shifts.