Modern literature increasingly emphasizes the need to take aperiodic activity into account when analyzing electroencephalogram and magnetoencephalogram (MEG) signals. There are a number of studies illustrating the benefits of this indicator in nocturnal sleep staging, however, aperiodic activity has not been studied in short-term wake-sleep and sleep-wake transitions. Objective: to describe qualitatively and quantitatively the dynamics of aperiodic activity during monotonous behavioral activity with multiple episodes of falling asleep and waking up. 25 subjects underwent a monotonous psychomotor test for 1 hour with simultaneous registration of a magnetoencephalogram. The dynamics of its execution (with multiple episodes of falling asleep and waking up) were compared with the dynamics of the power of alpha activity and the value of the aperiodic exponent – both visually and with the calculation of the Spearman correlation coefficient. In 23 subjects, the dynamics of the aperiodic exponent reflected changes in the quality of the psychomotor test execution. For 11 subjects, alpha activity and aperiodic activity had similar correlations with behavioral dynamics. Aperiodic activity was more informative for 5 subjects, and alpha activity was more informative for 9. Conclusions: aperiodic activity is an informative indicator of the level of vigilance and should be considered together with standard criteria based on the periodic component of brain electrical activity.