Short Objective Sleep Duration Research Articles

Association of Objective and Subjective Sleep Duration and Diurnal Cortisol Rhythm among Community‐Dwelling People Living with Dementia

AbstractBackgroundEvidence has shown that both short and long sleep duration have adverse effects on cognitive health in older adults. Although changes in sleep duration have been linked with alterations in the hypothalamic‐pituitary‐adrenal axis, research on the association between sleep duration and various components of diurnal cortisol rhythm is inconsistent. In addition, limited research has examined this association in community‐dwelling people living with dementia. The aim of this study is to examine the association of objective and subjective sleep duration and cortisol rhythm indicators in a community‐dwelling population living with dementia.MethodParticipants in the Healthy Patterns Sleep Study (NCT03682185) provided three saliva samples at wakening, 30 minutes after waking, and bedtime on two consecutive days. Diurnal cortisol rhythm indicators included waking cortisol, cortisol awaking response, diurnal cortisol slope, and bedtime cortisol. Objective sleep duration was measured by averaging actigraphy over three days, and subjective sleep duration was assessed by a single item from the Pittsburgh Sleep Quality Index. The average daily total sleep duration was grouped into three categories: ≤5 (short), ≥9 (long), and >5 & <9 (normal). 195 participants with valid cortisol and sleep data were used for analysis.ResultApproximately 60% (objective) or 45% (subjective) of the participants maintained seven to eight hours of sleep. Normal and long objective and subjective sleep duration preserved an intact diurnal cortisol rhythm. Short objective sleep duration, however, was associated with higher waking cortisol (p = 0.016) and diminished cortisol awaking response (p = 0.049), compared to normal sleep. No significance was found using subjective short sleep duration.ConclusionThis cross‐sectional study showed that objective short sleep duration was associated with disrupted cortisol rhythm. The findings suggest that neuroendocrine disturbance could be one mechanism linking sleep and dementia risk. Future studies are needed to confirm these findings using more sampling points in the morning. Additionally future research needs to consider the confounding sociodemographic and clinical characteristics such as race and dementia severity in a larger sample.

0409 Is insomnia with objective short sleep duration related to insufficient sleep drive or physiological hyperarousal?

Abstract Introduction IInsomnia with objective short sleep duration (OSSD) was found to be associated with higher risks of cardiometabolic disorders, and was therefore proposed to be a phenotype associated with higher physiological hyperarousal. Previous studies further reported that insomnia with OSSD had higher autonomic arousal as measured by heart rate variability (HRV) during sleep. Since sleep duration could be determined by the interplay of arousal and sleep drive and HRV during sleep could be influenced by sleep staging and quality, the present study examined the level of arousal and sleep drive prior to sleep with EEG power and HRV to further understand the phenotyping of insomnia. Methods Ninety-four insomnia patients participated in the study and went through one night of 8-hour PSG recording. They were divided, with a cut-off of PSG total sleep time of 6 hours, into two groups: an OSSD group (N=26; mean age=37.0 ±10.3; M:F=7:19; TST=286.21±87.21 min) and an objective normal sleep duration (ONSD) group (N=68, mean age=32.95 ±10.05, M:F=12: 56, TST=414.4±28.9 min). Resting-state EEG and EKG were recorded for a 6-min period, 3-min eye-opened (EO) with fixation focus and 3 mins eye-closed (EC), prior to bedtime. Results T-tests showed no significant difference in HRV measures (SDNN, RMSD, LF, HF, LF/HF) between the two groups, but shorter R-R interval for OSSD group than ONSD group. Mann-Whitney tests for EEG power showed significantly lower theta power at F3, F4, C3, C4, and O2, and higher sigma power at F3, C3, C4, O1, and O2 during EC, as well as lower theta power at C3 and higher sigma power at O2 during EO for OSSD group in comparison to ONSD group. Conclusion The results partially support that insomnia with OSSD is associated with physiological hyperarousal as indicated by faster heart rate and higher high frequency EEG power prior to sleep. However, the lower EEG theta power prior to sleep suggest that lower homeostatic sleep drive may also play a role for the insomnia with short objective sleep duration. Support (if any) Supported by Taiwan National Science and Technology Council

325 Stress-Induced Physiological Profiles Among Different Phenotype Insomniacs

Abstract Introduction Stress reactivity and autonomic nervous system (ANS) dysregulation have been suggested to be the pathophysiology of insomnia. Based on the finding PSG-measured short sleep duration was associated with higher morbidity of metabolic and cardiovascular disease. Vgontzas and Fernandez-Mandoza (2013) proposed that objective sleep duration is a biomarker for insomnia phenotypes. The phenotype with short objective sleep duration is associated with increased stress-related physiological hyperarousal. The present study aims to test this hypothesis by comparing the stress-induced cardiovascular reactivity between insomnia patients with short and long objective sleep durations. Methods 27 insomnia patients (age mean 34.48 ±12.87, Male: Female= 6:21) without comorbidity of psychiatric, medical or sleep disorders participated in this study. They went through one night of 8-hour PSG recording and were divided into two groups by their total sleep time with a cutoff of 6 hours. Nine participants were in short sleep duration group and 18 in longer sleep duration group. Psychophysiological reactivity profile, as recorded with EKG, skin conductance (SC), body temperature (BT), blood volume pulse (BVP), respiration rate (RR), was measured under three conditions: baseline resting state, arithmetic word problems solving, and recovery resting state. Results Both groups showed similar stress physiological response with increased heart rate (HR) and SC, nearly equivalent BT and BVP, and decreased RR when solving arithmetic problems, and opposite reaction during recovery resting state. Mann-Whitney U test comparing the changes from baseline resting state on all the psychophysiological measures between two phenotypes of insomnia showed no significant differences: stress-induced heart-rate (U=106, p=.119.) recovery heart-rate (U=44, p=.095), stress-induced skin conductance (U=104.5, p=.132),recovery skin conductance (U=51.5, p=.198), stress-induced body temperature (U=79, p=.897),recovery body temperature (U=60.5, p=.418), stress-induced blood volume pulse amplitude (U=77, p=1.0), and recovery blood volume pulse amplitude (U=69, p=.735), stress-induced respiration rate (U=76, p =.696), and recovery respiration rate (U=85, p=.658). Conclusion Our results indicate that the insomnia phenotypes with short and long objective sleep duration are not different in their stress-induced physiological responses. Future studies are needed to confirm these results and to explore other mechanisms for the increased metabolic and cardiovascular disease risk in insomnia patients with short objective sleep duration. Support (if any):

Objective sleep assessment in >80,000 UK mid-life adults: Associations with sociodemographic characteristics, physical activity and caffeine.

Normal timing and duration of sleep is vital for all physical and mental health. However, many sleep-related studies depend on self-reported sleep measurements, which have limitations. This study aims to investigate the association of physical activity and sociodemographic characteristics including age, gender, coffee intake and social status with objective sleep measurements. A cross-sectional analysis was carried out on 82995 participants within the UK Biobank cohort. Sociodemographic and lifestyle information were collected through touch-screen questionnaires in 2007-2010. Sleep and physical activity parameters were later measured objectively using wrist-worn accelerometers in 2013-2015 (participants were aged 43-79 years and wore watches for 7 days). Participants were divided into 5 groups based on their objective sleep duration per night (<5 hours, 5-6 hours, 6-7 hours, 7-8 hours and >8 hours). Binary logistic models were adjusted for age, gender and Townsend Deprivation Index. Participants who slept 6-7 hours/night were the most frequent (33.5%). Females had longer objective sleep duration than males. Short objective sleep duration (<6 hours) correlated with older age, social deprivation and high coffee intake. Finally, those who slept 6-7 hours/night were most physically active. Objectively determined short sleep duration was associated with male gender, older age, low social status and high coffee intake. An inverse 'U-shaped' relationship between sleep duration and physical activity was also established. Optimal sleep duration for health in those over 60 may therefore be shorter than younger groups.

0035 Long-sleepers and Insomnia with Short Objective Sleep Duration are Independently Associated with Short Telomere Length in the EPISONO Cohort

0035 Long-sleepers and Insomnia with Short Objective Sleep Duration are Independently Associated with Short Telomere Length in the EPISONO Cohort

Heart rate phenotypes and clinical correlates in a large cohort of adults without sleep apnea.

BackgroundNormal sleep is associated with typical physiological changes in both the central and autonomic nervous systems. In particular, nocturnal blood pressure dipping has emerged as a strong marker of normal sleep physiology, whereas the absence of dipping or reverse dipping has been associated with cardiovascular risk. However, nocturnal blood pressure is not measured commonly in clinical practice. Heart rate (HR) dipping in sleep may be a similar important marker and is measured routinely in at-home and in-laboratory sleep testing.MethodsWe performed a retrospective cross-sectional analysis of diagnostic polysomnography in a clinically heterogeneous cohort of n=1047 adults without sleep apnea.ResultsWe found that almost half of the cohort showed an increased HR in stable nonrapid eye movement sleep (NREM) compared to wake, while only 13.5% showed a reduced NREM HR of at least 10% relative to wake. The strongest correlates of HR dipping were younger age and male sex, whereas the periodic limb movement index (PLMI), sleep quality, and Epworth Sleepiness Scale (ESS) scores were not correlated with HR dipping. PLMI was however significantly correlated with metrics of impaired HR variability (HRV): increased low-frequency power and reduced high-frequency power. HRV metrics were unrelated to sleep quality or the ESS value. Following the work of Vgontzas et al, we also analyzed the sub-cohort with insomnia symptoms and short objective sleep duration. Interestingly, the sleep–wake stage-specific HR values depended upon insomnia symptoms more than sleep duration.ConclusionWhile our work demonstrates heterogeneity in cardiac metrics (HR and HRV), the population analysis suggests that pathological signatures of HR (nondipping and elevation) are common even in this cohort selected for the absence of sleep apnea. Future prospective work in clinical populations will further inform risk stratification and set the stage for testing interventions.