Sleep Extension Improves Neurocognitive Functions in Chronically Sleep-Deprived Obese Individuals

Abstract

BackgroundSleep deprivation and obesity, are associated with neurocognitive impairments. Effects of sleep deprivation and obesity on cognition are unknown, and the cognitive long-term effects of improvement of sleep have not been prospectively assessed in short sleeping, obese individuals.ObjectiveTo characterize neurocognitive functions and assess its reversibility.DesignProspective cohort study.SettingTertiary Referral Research Clinical Center.PatientsA cohort of 121 short-sleeping (<6.5 h/night) obese (BMI 30–55 kg/m2) men and pre-menopausal women.InterventionSleep extension (468±88 days) with life-style modifications.MeasurementsNeurocognitive functions, sleep quality and sleep duration.ResultsAt baseline, 44% of the individuals had an impaired global deficit score (t-score 0–39). Impaired global deficit score was associated with worse subjective sleep quality (p = 0.02), and lower urinary dopamine levels (p = 0.001). Memory was impaired in 33%; attention in 35%; motor skills in 42%; and executive function in 51% of individuals. At the final evaluation (N = 74), subjective sleep quality improved by 24% (p<0.001), self-reported sleep duration increased by 11% by questionnaires (p<0.001) and by 4% by diaries (p = 0.04), and daytime sleepiness tended to improve (p = 0.10). Global cognitive function and attention improved by 7% and 10%, respectively (both p = 0.001), and memory and executive functions tended to improve (p = 0.07 and p = 0.06). Serum cortisol increased by 17% (p = 0.02). In a multivariate mixed model, subjective sleep quality and sleep efficiency, urinary free cortisol and dopamine and plasma total ghrelin accounted for 1/5 of the variability in global cognitive function.LimitationsDrop-out rate.ConclusionsChronically sleep-deprived obese individuals exhibit substantial neurocognitive deficits that are partially reversible upon improvement of sleep in a non-pharmacological way. These findings have clinical implications for large segments of the US population.Trail registrationwww.ClinicalTrials.gov NCT00261898. NIDDK protocol 06-DK-0036

The effects of extended bedtimes on sleep duration and food desire in overweight young adults: A home-based intervention

“…Our finding that sleep extension (objectively measured) is feasible in real life settings is consistent with two recent reports where extending sleep duration (assessed by self-reported sleep diaries) had beneficial effects on neurocognitive function in habitually short sleeping healthy and obese individuals (16, 17). On average, our participants obtained 1.6 hours more sleep with extended bedtimes, which is comparable in magnitude to the difference in sleep duration reported in prior studies as having adverse effects of sleep restriction on diabetes and obesity risk (18-21).…”

Sleep, Cognition, and Normal Aging

“…One approach to improving overnight sleep is to extend total time in bed or adjust sleep/nighttime habits (e.g., by routinizing bedtimes). These behavior-based sleep extension manipulations have been linked to positive cognitive outcomes in adolescents, young adults, and middle-aged adults (e.g., Dewald-Kaufmann, Oort, & Meijer, 2013; Lucassen et al, 2014; Mah, Mah, Kezirian, & Dement, 2011; but see Sadeh, Gruber, & Raviv, 2003). One study is suggestive of a similar benefit in healthy older adults (Klerman & Dijk, 2008), but this study did not control for practice effects (Shipstead, Redick, & Engle, 2012).…”

The development of a clinically relevant sleep modification protocol for youth with Type 1 diabetes.

“…Furthermore, clinical trials with adult samples have demonstrated that extending sleep over six weeks to twelve months in natural environments is feasible (Cizza et al, 2011; Leproult, Deliens, Gilson, & Peigneux, 2015). Further, in non-obese adults, the additional sleep contributed to improved insulin sensitivity and glucose levels (Leproult et al, 2015) as well as neurocognition (Lucassen et al, 2014). …”