Effects of Sleep Loss and Chronic Stress on Executive Functioning

Sleep loss negatively affects cognition, but the individual variation is large, and findings on its impact on executive functioning (EF) are inconclusive. Previous literature indicates that chronic psychological stress is associated with impairments in EF, but there is a lack of research on the strength of this relationship and whether chronic stress moderates the effect of sleep loss on EF. Therefore, data from a large and ongoing within-subject sleep experiment (n = 201) were analyzed. Chronic stress was measured using the Perceived Stress Scale, and EF was assessed twice with the Design Fluency test: once following normal sleep (9 hours) and once following restricted sleep (4 hours). As hypothesized, EF showed a significant but small impairment following sleep loss, and there was a negative association between EF and chronic psychological stress. Interestingly, and contrary to the proposed two-hit model, chronic stress was not associated with an additional decrease in executive functioning. These findings clarify the effects of an ecologically valid sleep restriction on EF, and raise questions about the interaction between EF, chronic stress, and sleep loss.