The Effects of Sleep Variability in Youth

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

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.

Study Overview

• Status: Completed
• Conditions: Sleep Variability
• Intervention / Treatment: Behavioral: Irregular sleep

• Study Type: Interventional
• Enrollment (Actual): 41
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong
    • Sleep Research Clinic & Laboratory, Department of Psychology, The University of Hong Kong

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 25 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Irregular sleep; 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; Experimental-induced sleep variability
No Intervention: Regular sleep; 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?

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

Collaborators and Investigators

• Sponsor: The University of Hong Kong
• Investigators: Principal Investigator: Dr. Shirley X. Li, The University of Hong Kong

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2019
• Primary Completion (Actual): January 1, 2021
• Study Completion (Actual): January 1, 2021

Study Registration Dates

• First Submitted: June 15, 2019
• First Submitted That Met QC Criteria: February 7, 2020
• First Posted (Actual): February 10, 2020

Study Record Updates

• Last Update Posted (Actual): May 11, 2021
• Last Update Submitted That Met QC Criteria: May 9, 2021
• Last Verified: May 1, 2021

More Information

Terms related to this study

• Other Study ID Numbers: EA1708030

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No