[Effect of time of day and fatigue on psychophysiological functions of an operator]

Time of the day has been found to have an important effect on the intersystemic relations of the psychophysiological functions of an operator, while the activity of the cardiovascular system (CVS) depended not only on the time of the day but also, to a large extent, on fatigue. The morning time potentiated the manifestations of staying awake but the evening time--those of fatigue. Relatively less pronounced changes in the functioning of an organism in the morning, induced by fatigue, gave evidence for both a higher level of activation of the organism and relatively higher level of the central interactions in it. Accumulated fatigue potentiated the manifestations of daily variations of the functional activity of an operator. The second subsequent night shift has been shown to have a higher initial activity of the CVS, as compared to the second day shift, and it was characterised by an increased difference between systolic and diastolic blood pressure as compared to the first night shift. Effect of overshift fatigue shows an increase in the vascular component and a decrease in the cardiac one in the regulation of blood circulation. Mental performance was shown to be less dependent on time of the day and fatigue as compared to the CVS activity. Short-term memory was more sensitive to fatigue and more often correlated with the parameters of the CVS than attention did.