Consecutive Nights of Moderate Sleep Loss Does Not Affect Mood in Healthy Young Males

• Main Authors: Christiana Harous, Gregory D. Roach, Thomas G. Kontou, Ashley J. Montero, Nicole Stuart, Charli Sargent
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Clocks & Sleep
• Subjects: mood disturbance; emotion; wellbeing; profile of mood states; sleep restriction; fatigue
• Online Access: https://www.mdpi.com/2624-5175/3/3/31

Sleep loss causes mood disturbance in non-clinical populations under severe conditions, i.e., two days/nights of sleep deprivation or a week of sleep restriction with 4–5 h in bed each night. However, the effects of more-common types of sleep loss on mood disturbance are not yet known. Therefore, the aim of this study was to examine mood disturbance in healthy adults over a week with nightly time in bed controlled at 5, 6, 7, 8 or 9 h. Participants (<i>n</i> = 115) spent nine nights in the laboratory and were given either 5, 6, 7, 8 or 9 h in bed over seven consecutive nights. Mood was assessed daily using the Profile of Mood States (POMS-2). Mixed-linear effects models examined the effect of time in bed on total mood disturbance and subscales of anger-hostility, confusion-bewilderment, depression-dejection, fatigue-inertia, tension-anxiety, vigour-activity and friendliness. There was no effect of time in bed on total mood disturbance (<i>F</i>(4, 110.42) = 1.31, <i>p</i> = 0.271) or any of the subscales except fatigue-inertia. Fatigue-inertia was higher in the 5 h compared with the 9 h time in bed condition (<i>p</i> = 0.012, <i>d</i> = 0.75). Consecutive nights of moderate sleep loss (i.e., 5–7 h) does not affect mood but does increase fatigue in healthy males.