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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Investigating the effect of light on sleep and performance during two night-shift protocols
Scientific title
Exploring human cognitive effectiveness in an encapsulated work environment: Toward a circadian entrainment strategy using smart LED lighting for adults during a night-shift protocol
Secondary ID [1] 302486 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
sleep 319325 0
circadian rhythms 319326 0
cognitive performance 319732 0
Condition category
Condition code
Mental Health 317294 317294 0 0
Studies of normal psychology, cognitive function and behaviour

Study type
Description of intervention(s) / exposure
The intervention is lighting throughout a simulated submarine night shift (optimised lighting versus control lighting) on four night shifts during an eight-day laboratory protocol administered by sleep technicians. The optimised lighting intervention will be high intensity lighting (>200 lux) in the ‘cool’ blue-end wavelength range of the light spectrum during the times that we want to shift circadian rhythms (i.e. during the four x 8-hour work shifts) via automated adjustment to the laboratory lighting. During other times, the intervention lighting will be dimmed (<100lux) and the spectral content will be less ‘cool’ to avoid circadian shifts in the opposite direction than is intended. During the night shifts, participants will complete cognitive performance tasks, such as reaction time tasks and solving simple arithmetic equations. Adherence will be assessed via continuous video recording of the laboratory. All participants will experience the intervention condition, with a four-week wash-out period between the intervention and the control condition (counter-balanced).
Intervention code [1] 318780 0
Treatment: Other
Comparator / control treatment
The control condition is standard ‘office-like’ lighting of medium intensity (at approximately 100 lux) and on the ‘warmer’, red-light end of the light spectrum during the whole study, except when attempting sleep (<1 lux). Aside from the lighting, all aspects of the study protocol are the same between the intervention and the control condition, for instance, participants will also complete the four 8-hour night shifts during the control condition.
Control group

Primary outcome [1] 325355 0
Objective performance on the psychomotor vigilance task (reaction time).
Timepoint [1] 325355 0
Performance on the final night shift (day 7) compared to baseline (pre-intervention).
Secondary outcome [1] 387598 0
Circadian rhythm entrainment, measured by dim-light melatonin onset (salivary concentration).
Timepoint [1] 387598 0
The final day of the experiment (day 8) compared to baseline (pre-intervention).
Secondary outcome [2] 388898 0
core body temperature rhythms (ingestible capsule)
Timepoint [2] 388898 0
the final day of the experiment (day 8) compared to baseline (pre-intervention)

Key inclusion criteria
• Age, 18 years and older
• Defence Navy eligibility requirements
o Upper age-limit compatible with minimum service requirements
o Australian Citizen
o Passed year 10 English and Maths
o Normal health and fitness
o BMI >18.5 and <32.9 kg/m²
• Report normal sleep (typical habitual sleep time of 6-8 hours, with a typical bedtime between 10pm-12am.
• Willing and agree to follow protocol requirements, including;
o Screening assessments
o Home testing
o Strict time and activity schedules (sleep, activity/work, mealtime) during each 8-day in-laboratory visit.
Minimum age
18 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• Language difficulties that may preclude informed consent.
• Any severe cognitive impairments, mental illnesses, or intellectual disabilities that may preclude informed consent.
• Self-reported sleep disorder (prior diagnosis of insomnia, obstructive sleep apnea, restless legs syndrome or any other recognised clinical sleep problem).
• Extreme evening/morning types (according to screening questionnaire measures).
• Shift work in the past 6 months, or intentions to undertake shift work prior to study completion.
• International travel (>2 hour time shift) in the last 6 months, or anticipated travel prior to study completion.
• Any relevant history of psychiatric, neurological, heart, or lung diseases/disorders.
• Any significant eye- or cervical spine related disease, disorder or surgery that may interfere with simulated Defence work-shift schedules or circadian physiology.
• Habitual caffeine consumption >250 mg (~2-3 cups of coffee) per day.
• Current or recent (last 6 months) smoker.
• Unwilling or unable to abstain from alcohol or any other recreational drug during the laboratory components of the study.
• Reported use of any drugs or medications that may impact sleep (e.g. benzodiazepines, ‘z-drugs’, melatonin, anti-psychotics, anti-depressants).

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 306911 0
Government body
Name [1] 306911 0
Australian Government, Department of Defence
Address [1] 306911 0
PO Box 1500
Edinburgh SA 5111
Country [1] 306911 0
Funding source category [2] 306912 0
Name [2] 306912 0
Flinders University
Address [2] 306912 0
Sturt Road
Bedford Park SA 5042
Country [2] 306912 0
Primary sponsor type
Flinders University
Adelaide Institute for Sleep Health
Box 6, 5 Laffer Drive
Bedford Park SA 5042
Secondary sponsor category [1] 307816 0
Name [1] 307816 0
Address [1] 307816 0
Country [1] 307816 0

Ethics approval
Ethics application status
Ethics committee name [1] 307062 0
Southern Adelaide Clinical Human Research Ethics Committee
Ethics committee address [1] 307062 0
Flinders Medical Centre
Flinders Dr
Bedford Park SA 5042
Ethics committee country [1] 307062 0
Date submitted for ethics approval [1] 307062 0
Approval date [1] 307062 0
Ethics approval number [1] 307062 0

Brief summary
The overarching aim of this project is to investigate a strategy to help maximise human cognitive performance in an encapsulated shift-work environment through evidence-based LED lighting design interventions optimised to support successful circadian physiology entrainment. We will conduct a randomised counter-balanced crossover experimental study designed to investigate the effectiveness of standard versus optimised LED lighting systems on cognitive performance, circadian entrainment, and objective sleep parameters during an 8 day simulated shift-work schedule in a laboratory environment.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 105894 0
Prof Peter Catcheside
Address 105894 0
Adelaide Institute for Sleep Health
Box 6, 5 Laffer Drive
Bedford Park SA 5042
Country 105894 0
Phone 105894 0
Fax 105894 0
Email 105894 0
Contact person for public queries
Name 105895 0
Dr Hannah Scott
Address 105895 0
Adelaide Institute for Sleep Health
Box 6, 5 Laffer Drive
Bedford Park SA 5042
Country 105895 0
Phone 105895 0
Fax 105895 0
Email 105895 0
Contact person for scientific queries
Name 105896 0
Dr Hannah Scott
Address 105896 0
Adelaide Institute for Sleep Health
Box 6, 5 Laffer Drive
Bedford Park SA 5042
Country 105896 0
Phone 105896 0
Fax 105896 0
Email 105896 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No/undecided IPD sharing reason/comment
What supporting documents are/will be available?
No other documents available
Summary results
No Results