L.V. Poskotinova - Dr.Sci. (Biol.), Ph.D. (Med.), Associated Professor, Head of Biorhythmology, The Institute of Environmental Physiology, Ural Branch, Russian Academy of Sciences, Arkhangelsk, Russia. E-mail: liliya200572@mail.ru E.V. Krivonogova - Ph. D. (Biol.), Senior Research Scientist, The Institute of Environmental Physiology, Ural Branch, Russian Academy of Sciences, Arkhangelsk, Russia. E-mail:elena200280@mail.ru M.A. Ovsyankina - Lecturer, Arkhangelsk Pedagogical College, Arkhangelsk, Russia. E-mail: marinaovsyankina@mail.ru A.V. Melnikova - Lecturer, Arkhangelsk Pedagogical College, Arkhangelsk, Russia. E-mail: anjapus@mail.ru