[Chronotype of human in the north]

Long term acting climatic and social factors of the North causes desynchronization of human circadian system that can lead to increase in risk of age-associated diseases. Earlier on small sample we have shown, that the higher latitude of residing in the North, the higher rate of occurrence of late chronotype. It is noted also, that parameters of daily rhythm at late chronotype person are less expressed, than at early one. The purpose of present research is to study distribution of rates of various chronotypes depending on latitude of residing. Chronotypes were assessed by the Munich Chronotype Questionnaire (MCTQ). Our study includes 772 inhabitants of Komi Republic. It was shown that there is a significant shift to prevalence of late chronotype among inhabitants of the North. Thus, increase in rate of persons with late chronotype, circadian system of which is most sensitive to negative action climatic and social factors of the North, can be one of the causes of its desynchronization and increasing in risk of age-associated diseases at northerners.