The Effects of Sleep Variability in Youth

Study Overview
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Brief Summary
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Daily sleep variability is prevalent in the young populations, yet its effects remain less clear. The experimental study aims to examine the impacts of intraindividual daily sleep variability on sleep characteristics, cardiometabolic regulations and daytime functioning in college students.

Official Title
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The Effects of Sleep Variability on Sleep Quality, Daytime Functioning and Cardiometabolic Regulation in Youth

Conditions
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Sleep Variability

Intervention / Treatment
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* Behavioral: Irregular sleep


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Habitual sleep duration > 7 h/day. Exclusion Criteria: Extreme morning- nor extreme evening-chronotype With sleep problems With mood and anxiety problems With excessive daytime sleepiness Have history of any chronic medical condition and on regular medication.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 25 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Irregular sleep<br>Participants sleep in lab while being monitored with polysomnography for 8 consecutive nights, including an adaptation night and a baseline night of 7.5 h time in bed (0:00-7:30). Afterwards, they are instructed to sleep in bed on a schedule alternated between 6 h, i.e. 1:30-7:30, and 9 h, i.e. 22:30-7:30). | Behavioral: Irregular sleep<br>* Experimental-induced sleep variability<br>|
| No Intervention: Regular sleep<br>Participants sleep in lab while being monitored with polysomnography for 8 consecutive nights of 7.5 h time in bed (0:00-7:30). | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Subjective sleepiness | As measured by the Stanford Sleepiness Scalen (SSS) | 7 days (every morning and evening) | 
| Mood | mood state as measured by the Positive and Negative Affect Scale (PANAS). | 7 days (every morning and evening) | 
| Cognitive functioning - Sustained attention | Sustained attention as measured by psychomotor vigilance task (PVT) | 7 days (every morning and evening) | 
| Cognitive functioning - processing speed | Processing speed as measured by Digit Symbol Substitution Test (DSST) | 7 days | 
| Cognitive functioning - inhibition | Inhibition as measured by stop-signal reaction time (SSRT) | 7 days | 
| Cognitive functioning - working memory | working memory as measured by 2-back task | 7 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sleep quality | Actual sleep time, sleep onset latency, wake after sleep onset and night time arousals as measured by actigraphy and PSG. Sleep satisfactory and dreams as measured by sleep diary. | 7 days | 
| Sleep architecture | Sleep stagings (e.g., SWS%, REM duration) and sleep EEG spectrums as analysed from PSG recordings. | 7 days | 
| Heart rate variability | Resting heart rate and heart rate variability are measured in the morning, evening and during the night. | 7 days | 
| Cortisol awakening response | Cortisol awakening response is assessed before and after the manipulation. | baseline, post-intervention |