[Synchronization of various physiological parameters during the waking state in man (author's transl)]

Various physiological parameters (EEG, EKG, EOG, EMG), and behavioural activities were measured during 8 working hours in 40 subjects divided into 4 groups according to their age and occupation (35 and 50 years, specially skilled workmen and university workers). Several moments of synchronization between the different parameters were defined; they were characterized by reduction or suppression of the theta index, an increase in the alpha index, an increase in number of blinkings, a drop in muscle tone, and variations in heart rate, accompanied by modifications in work activity. The variation observed during these synchronized moments is an overall change in all the parameters and is not systematically related to just one of them. The synchronized moments last for about 8 minutes and are more frequent and better individualized in university personnel than in workmen. The average interval between them is 93 minutes with large intra and inter-variability between individuals. They are longer in 50-year-old subjects whatever the type of activity. The authors compare these moments of synchronization with ultradian rhythms described by other authors.