A Proposal on the Novel Method to Estimate Optimal Sleep Duration Based on Self-Reported Survey Data

Background: Many adolescents have a sleep debt. Individuals sleeping for their optimal sleep duration are expected to experience no sleepiness. Then, it is important to recognize one’s optimal sleep duration to reduce sleep debt. However, there is no simple method to determine this value. Since body mass index and sleep duration exhibit a U-shaped association, it is expected that a person taking optimal sleep duration would show no marked deviation from the mean body mass index value for the population evaluated. By using self-reported sleepiness and standardized body mass index, this study aimed to estimate individual optimal sleep duration. Methods: Data from 2540 grade 5 - 11 students were used. Students who declared no sleepiness during class and also had a gender- and grade-standardized body mass index of ±1.5 were termed ideal students. The average sleep durations of ideal students were compared with those of non-ideal students. The differences of sleep duration between ideal and no-ideal students were added to habitual sleep duration of each non-ideal student to obtain assumed optimal sleep duration. A multiple regression line to predict assumed optimal sleep duration was calculated using the least squares method. Results: The mean sleep duration of 666 ideal students exceeded the lower limit of daily sleep duration proposed as “may be appropriate” for children aged 6 - 17 years by National Sleep Foundation of the USA, being longer than those of non-ideal students. Significant regression formula for assumed optimal sleep duration was obtained (adjusted R2 = 0.996, p Conclusions: No contradiction was identified in the sleep duration obtained from ideal students as with optimal sleep duration. Although further studies to confirm the current estimation are needed, a simple formula to estimate individual optimal sleep duration through easily obtainable parameters was proposed.

Alzheimer's disease with sleep insufficiency:a cross-sectional study on correlations among clinical characteristics,orexin,its receptors,and the bloodbrain barrier

Previous studies have shown that reduced sleep duration,sleep fragmentation,and decreased sleep quality in patients with Alzheimer's disease are related to dysfunction in orexin signaling.At the same time,blood-brain barrier disruption is considered an early biomarker of Alzheimer's disease.However,currently no report has examined how changes in orexin signaling relate to changes in the blood-brain barrier of patients who have Alzheimer's disease with sleep insufficiency.This cross-sectional study included 50 patients with Alzheimer's disease who received treatment in 2019 at Beijing Tiantan Hospital.Patients were divided into two groups:those with insufficient sleep(sleep duration≤6 hours,n=19,age 61.58±8.54 years,10 men)and those with normal sleep durations(sleep duration>6 hours,n=31,age 63.19±10.09 years,18 men).Demographic variables were collected to evaluate cognitive function,neuropsychiatric symptoms,and activities of daily living.The levels of orexin,its receptor proteins,and several blood-brain barrier factors were measured in cerebrospinal fluid.Sleep insufficiency was associated with impaired overall cognitive function that spanned multiple cognitive domains.Furthermore,levels of orexin and its receptors were upregulated in the cerebrospinal fluid,and the blood–brain barrier was destroyed.Both these events precipitated each other and accelerated the progression of Alzheimer's disease.These findings describe the clinical characteristics and potential mechanism underlying Alzheimer's disease accompanied by sleep deprivation.Inhibiting the upregulation of elements within the orexin system or preventing the breakdown of the blood-brain barrier could thus be targets for treating Alzheimer's disease.

Optimal Total Sleep Duration per Day to Maintain Health-Related Quality of Life in Male Collegiate Athletes:A Cross-Sectional Study

Purpose This study investigated the optimal total sleep duration per day required by collegiate athletes to maintain the physical and mental health-related quality of life(HRQOL),compared with non-athlete students.Methods In this cross-sectional study,a questionnaire survey was conducted to assess demographic variables,lifestyle and sleep habits,and HRQOL in 392 collegiate students(non-athletes,n=174;athletes,n=218).Physical component summary(PCS)and mental component summary(MCS)were assessed using the short-form-8 health survey.Participants with both good PCS and MCS were defined as having a good HRQOL.To confirm an association between the total sleep duration per day and good HRQOL,logistic regression analyses were conducted in non-athlete students and collegiate athletes separately.Subsequently,receiver-operating curve(ROC)analyses were performed for the detection of the cut-off point of total sleep duration per day sufficient to maintain a good HRQOL.Results The average total sleep duration per day was 7 h 19 min for collegiate athletes,and 78.9%of them had a worse PCS.The cut-off point of total sleep duration per day to maintain good HRQOL for collegiate athletes was 7.92 h(area under ROC,0.64;P=0.038;sensitivity,75.4%;specificity,57.9%),which was longer than 6.79 h for non-athlete students.Conclusion Collegiate athletes required longer nocturnal sleep than non-athlete students.Nevertheless,their habitual nocturnal sleep duration was shorter compared to their optimal duration;around 70%of them faced chronic insufficient sleep.Improving sleep habits and sleep education is important in maintaining their good health-related quality of life.

Isolated Thyrotropin Elevation is Associated with Insufficient Night-sleep in Night-sleep Restricted Subjects

Mild thyroid stimulating hormone （TSH） elevations are highly prevalent whereas large proportion of individuals with TSH elevations is without chronic autoimmune thyroid diseases.TSH secretion exhibits a daily circadian rhythm,and we previously reported that individuals with sleep disorders have significantly higher TSH levels than controls.