Morning Bright Light Therapy and Daytime Functioning in University Students
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18+
SponsorThe Hong Kong Polytechnic University
About this trial
This study tests whether a week of morning bright light therapy changes how well healthy young adults sleep and how alert, positive, and mentally sharp they feel during the day.
Morning light is the body's main signal for keeping its internal clock and sleep-wake timing on track. Many university students keep irregular hours and spend most of the day indoors, where light is far dimmer than daylight. This study asks whether adding a short, bright morning light session can help.
Each participant takes part for two weeks. For one week they use a bright light box for 30 minutes each morning, shortly after waking; for the other week they keep their usual lighting. The order of the two weeks is decided at random, and each person serves as their own comparison.
Throughout both weeks, sleep is tracked with a wrist-worn Fitbit and a short daily diary. Participants also rate their sleepiness and mood, complete brief computer-based attention and memory tasks, and take part in a short interview at the end about their experience.
The study compares the bright-light week with the usual-light week to see whether morning bright light improves sleep regularity and efficiency, reduces daytime sleepiness, lifts mood, or affects thinking performance. The trial is being conducted in waves; a first wave has completed and a second wave is planned, pending additional funding.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Enrolled university student
Aged 18 years or older
Generally healthy, with no diagnosed sleep disorder (sleep quality screened using the Pittsburgh Sleep Quality Index)
Residing in shared student housing
Disqualifiers
Diagnosed insomnia or other diagnosed sleep disorder
Other medical, psychiatric, or neurological condition that could affect sleep, mood, or cognition
Trial design
Design model
Crossover
Treatments tested in this trial
Bright light therapy (10,000 lux light box)
DeviceSelf-administered 30-minute session of 10,000 lux (photopic) bright light each morning, approximately 30 minutes after waking, for one week, using a standard 10,000-lux light therapy lamp positioned per manufacturer guidance. Stimulus characterized in melanopic units (melanopic equivalent daylight illuminance ≈ 8,989 lux).
Treatment groups
153 Participants
are divided into 2 treatment groupsGroup A: Morning Bright Light TherapyExperimental treatment 1 intervention
Group B: Usual Light (Control)No intervention 0 interventions
Trial outcomes
Primary outcomes
1
Sleep regularity
Regularity of sleep timing derived from wrist-worn Fitbit actigraphy and a daily sleep diary (e.g., day-to-day variability in sleep onset and offset). Condition-week values are compared between the bright-light week and the usual-light week.
Time frame
Recorded continuously across each 1-week condition (bright-light week and usual-light week).2
Daytime sleepiness (Karolinska Sleepiness Scale)
Subjective daytime sleepiness rated on the 9-point Karolinska Sleepiness Scale (KSS) at fixed times of day. Condition-week values are compared between the bright-light week and the usual-light week.
Time frame
Assessed daily at fixed times across each 1-week condition (bright-light week and usual-light week).3
Positive affect (PANAS Positive Affect subscale)
Positive affect measured with the Positive and Negative Affect Schedule (PANAS) positive-affect subscale. Condition-week scores are compared between the bright-light week and the usual-light week.
Time frame
End of each 1-week condition (bright-light week and usual-light week).4
Cognitive performance (computer-based battery)
Objective cognitive performance on a computer-based battery (Stroop, Flanker, Corsi block-tapping, and verbal span tasks). Condition-week performance is compared between the bright-light week and the usual-light week.
Time frame
End of each 1-week condition (bright-light week and usual-light week).Sponsors and contacts
Click on the lead sponsor to view all of their trials.
The Hong Kong Polytechnic University
Lead sponsor
Northumbria University
Collaborator
Source ClinicalTrials.gov