Uruguayan dance students: A model to unravel the associations between circadian, sleep, and mood disturbances

Background: Current evidence supports associations between circadian, sleep, and mood disturbances. However, it is still debated to what extent different chronobiological and mood variables act independently or in synergy to impact health. Methods: This study assesses how these variables interact to affect depressive symptoms and sleep quality in 26 Uruguayan dancers (age=22.27±2.43) training in the morning (n=9) or in the night shift (n=17). Participants completed the Munich Chronotype Questionnaire, the Pittsburgh Sleep Quality Index, and the Beck Depression Inventory-II. Results: Participants reported high social jetlag (1.58±1.45h), late chronotypes (05:43±01:35), and poor sleep quality (6.77±2.67), while adequate sleep duration (7.10±1.31h) and minimal depression (7.15±3.62), without differences across shifts. Depressive symptoms increased as sleep quality worsened (F(1,21)=20.66, p<0.001). In addition, sleep duration interacted with the shift to explain depressive mood (F(1,21)=4.06, p=0.057), with participants in the morning shift showing higher depressive symptoms with decreased sleep duration. Furthermore, sleep quality deteriorated as social jetlag increased (F(1,20)=14.82, p=0.001), particularly in more depressed individuals. Conclusions: Our findings indicate that social, circadian, sleep, and mood variables are inextricably linked in this population of dancers.