Frequency and Correlates of Sleep Debt in St. Petersburg

Abstract

Purpose

During weekdays, many of us fail meeting their physiologic sleep need. During weekends, however, when given additional sleep opportunity, homeostatic sleep pressure will typically lead to longer bedtimes, manifesting the cumulative sleep debt. This study aims at examining the prevalence and determinants of sleep debt, as indicated by the presence of ≥ 2 h weekend bedtime prolongation, in a general population.
Methods

We studied 257 healthy subjects living in St. Petersburg, Russia. All participants indicated their habitual bedtimes during weekdays and weekends, and completed the Epworth Sleepiness Scale (ESS), Fatigue Severity Scale, Fatigue Impact Scale, Pittsburgh Sleep Quality Index, and Hospital Anxiety and Depression Scale.
Results

One-hundred-three participants (40%) exhibited a relevant sleep debt (≥ 2 h weekend–weekday difference in habitual bedtime). Compared to participants without sleep debt, the frequency of excessive daytime sleepiness (ESS score ≥ 11)—but not of fatigue, impaired sleep quality and mood disturbances—was higher in participants with sleep debt (21% vs. 10%, p = 0.01). Multiple regression analysis revealed younger age, higher ESS and lower body mass index as independent associates of sleep debt.
Conclusions

Sleep debt appeared to be very common among healthy subjects, and independently associated with younger age, higher ESS scores and lower BMI. However, the presence of sleep debt did not have an impact on fatigue or mood, as measured by validated questionnaires.