Adults 50 to 65, any sex, with Shift-Work Sleep Disorder or Shift-Work Related Sleep Disturbance. Patients with the condition only — healthy volunteers not accepted.
Results — posted to ClinicalTrials.gov
Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.
Total Sleep Time (TST)Primary· The TST averaged for up to 3 intervention nights (in minutes) will be compared between groups.
TST is calculated as minutes of sleep in the main sleep episode between shifts, derived from actigraphy data collected in 60 s epochs. The investigators will use a commercial software package to score the sleep. For control group participants who will sleep ad-lib, TST will be calculated for the major sleep episode but also will be summed across sleep episodes if they sleep in more than one bout.
Group
Value
95% CI
Control (Group A)
338
± 68.7
8-h Afternoon-Evening Sleep (Group B)
387
± 53.2
8-h Free Sleep (Group C)
428
± 66.7
Sleep Fragmentation Index (FI)Primary· The FI averaged for intervention nights 2 and 3 will be compared between groups.
FI will be calculated as the number of times that sleep was terminated after 1 minute, expressed as a percentage of total estimated sleep time, using actigraphy data and commercial software to calculate it.
Group
Value
95% CI
Control (Group A)
22.15
± 15.49
8-h Afternoon-Evening Sleep (Group B)
34.94
± 22.01
8-h Free Sleep (Group C)
29.25
± 15.45
Wake After Sleep Onset (WASO)Primary· The WASO averaged for intervention nights 2 and 3 will be compared between groups.
WASO is an objective sleep quality measure and will be calculated as the duration (in minutes) of all awakenings during the main sleep episode measured with actigraphy, and calculated using commercial software.
Group
Value
95% CI
Control (Group A)
38.85
± 32.69
8-h Afternoon-Evening Sleep (Group B)
83.18
± 57.96
8-h Free Sleep (Group C)
70.06
± 43.6
Subjective Sleep QualityPrimary· Subjective Sleep quality (refreshment) averaged for intervention nights 2 and 3 will be compared between groups.
Participants will report their subjective sleep quality daily upon awakening from the main sleep episode. Multiple measures of subjective sleep quality will be assessed, but the investigators will report how refreshed the participant feels after awakening as the outcome. This is rated on a 7-point scale, where 7 is the best and 1 is the worst.
Group
Value
95% CI
Control (Group A)
3.25
± 1.03
8-h Afternoon-Evening Sleep (Group B)
3.06
± 1.36
8-h Free Sleep (Group C)
3.13
± 0.88
Subjective Alertness Via Karolinska Sleepiness Scale (KSS)Primary· The KSS score taken at the end of the final night shift (night shift 3) during the intervention block will be compared to that at baseline.
Participants will complete the Karolinska Sleepiness Scale (KSS) as a measure of subjective alertness immediately following each night shift. The KSS is a Likert scale ranging from 1, extremely alert, to 9, extremely sleepy.
subjective sleepiness worsened between baseline and end of treatment
Group
Value
95% CI
Control (Group A)
5
8-h Afternoon-Evening Sleep (Group B)
0
8-h Free Sleep (Group C)
3
subjective sleepiness did not change between baseline and end of treatment
Group
Value
95% CI
Control (Group A)
3
8-h Afternoon-Evening Sleep (Group B)
3
8-h Free Sleep (Group C)
4
subjective sleepiness improved between baseline and end of treatment
Group
Value
95% CI
Control (Group A)
1
8-h Afternoon-Evening Sleep (Group B)
4
8-h Free Sleep (Group C)
2
Sustained AttentionPrimary· PVT mean of slowest 10% of responses measured at the start of the final night shift (night shift 3) during the intervention block will be compared between groups.
The psychomotor vigilance task (PVT) is a test of visual reaction time (RT) in which the participant is asked to maintain the fastest possible RTs to a simple visual stimulus for several minutes. The inter-stimulus interval varies randomly between 2-10 seconds. While there are a number of standard performance metrics that can be obtained from each PVT, we have looked at the slowest 10% of responses.
Group
Value
95% CI
Control (Group A)
308.75
± 0
8-h Afternoon-Evening Sleep (Group B)
393.27
± 87.34
8-h Free Sleep (Group C)
470.96
± 126.80
Subjective EnergyPrimary· Subjective Energy measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.
A Visual Analogue Scale (VAS) will be used to assess subjective energy level. The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. energetic-sluggish. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as subjective energeticness. Thus, scores on the scale range from 0 to 100 with lower scores indicating greater subjective energy.
Group
Value
95% CI
Control (Group A)
50.07
± 27.17
8-h Afternoon-Evening Sleep (Group B)
57.72
± 28.95
8-h Free Sleep (Group C)
52.07
± 22.53
Subjective Stress Via Visual Analog Scale (VAS)Primary· Subjective Stress via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.
A Visual Analogue Scale (VAS) will be used to assess subjective stress.The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. relaxed-stressed. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as Subjective Stress. Thus, scores on the scale range from 0 to 100 with higher scores indicating greater subjective stress.
Group
Value
95% CI
Control (Group A)
58.99
± 32.33
8-h Afternoon-Evening Sleep (Group B)
68.84
± 20.29
8-h Free Sleep (Group C)
76.52
± 19.53
Subjective Calmness Via Visual Analog Scale (VAS)Primary· Subjective Calmness via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.
A Visual Analogue Scale (VAS) will be used to assess subjective Calmness. The VAS consists of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. calm-excited. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as Subjective Calmness. Thus, scores on the scale range from 0 to 100 with lower scores indicating greater subjective calmness.
Group
Value
95% CI
Control (Group A)
80.14
± 19.64
8-h Afternoon-Evening Sleep (Group B)
78.34
± 15.42
8-h Free Sleep (Group C)
78.51
± 14.54
Subjective Health Via Visual Analog Scale (VAS)Primary· Subjective Health via VAS measurements taken at the end of the final night shift (night shift 3) in the intervention block will be compared between groups.
Visual Analogue Scales (VAS) will be used to assess subjective health. VAS consist of a 100mm horizontal line with each end of the line labeled with the extremes of a subjective continuum, e.g. healthy-sick. The Participant indicates a position on the line that best describes how they feel at that moment. Distance from the left end of the scale (0) to the indicated point will be measured in mm and reported as Subjective Health. Thus, scores on the scale range from 0 to 100 with lower scores indicating greater subjective health.
Group
Value
95% CI
Control (Group A)
75.08
± 15.12
8-h Afternoon-Evening Sleep (Group B)
78.88
± 19.05
8-h Free Sleep (Group C)
74.96
± 16.78
Fatigue and Inter-Shift RecoverySecondary· OFER15 scores from the end of the third night shift in the Baseline to the end of the Intervention block will be compared between groups.
The Occupational Fatigue Exhaustion Recovery Scale (OFER 15), which consists of 15 questions about acute fatigue and recovery between shifts, will be used. Each of the 15 questions is answered on a Likert scale which ranges from 0 (Strongly Disagree) to 6 (Strongly Agree). The OFER15 will be completed immediately after the third night shift in the Baseline block and at the end of the third night shift in the Intervention block.
Participants whose fatigue scores worsened between baseline and end of intervention.
Group
Value
95% CI
Control (Group A)
3
8-h Afternoon-Evening Sleep (Group B)
2
8-h Free Sleep (Group C)
4
Participants whose fatigue scores improved between baseline and end of intervention.
Group
Value
95% CI
Control (Group A)
5
8-h Afternoon-Evening Sleep (Group B)
4
8-h Free Sleep (Group C)
4
Participants whose refreshment scores worsened between baseline and end of intervention.
Group
Value
95% CI
Control (Group A)
3
8-h Afternoon-Evening Sleep (Group B)
3
8-h Free Sleep (Group C)
7
Participants whose refreshment scores did not change between baseline and end of intervention.
Group
Value
95% CI
Control (Group A)
0
8-h Afternoon-Evening Sleep (Group B)
1
8-h Free Sleep (Group C)
0
Participants whose refreshment scores improved between baseline and end of intervention.
Group
Value
95% CI
Control (Group A)
5
8-h Afternoon-Evening Sleep (Group B)
2
8-h Free Sleep (Group C)
1
Subjective StressSecondary· Subjective stress will be assessed immediately after the third night shift in the Baseline and Intervention blocks and the change will be compared between groups.
The investigators will collect subjective measures of daily stress using a validated questionnaire, the Perceived Stress Scale (PSS), a 10-item self-report measure that allows a person to indicate stressful events that they have experienced in the past week. Each question is answered on a 5-item scale indicating the frequency, from 1 (never) to 5 (very often).
participants whose perceived stress worsened from baseline to end of intervention.
Group
Value
95% CI
Control (Group A)
3
8-h Afternoon-Evening Sleep (Group B)
3
8-h Free Sleep (Group C)
2
participants whose perceived stress did not change from baseline to end of intervention.
Group
Value
95% CI
Control (Group A)
1
8-h Afternoon-Evening Sleep (Group B)
1
8-h Free Sleep (Group C)
2
participants whose perceived stress improved from baseline to end of intervention.
Group
Value
95% CI
Control (Group A)
5
8-h Afternoon-Evening Sleep (Group B)
2
8-h Free Sleep (Group C)
5
Adverse events — posted to ClinicalTrials.gov
Time frame: Through each individual's study completion. This was from the start of data collection for an individual until the end of data collection for the individual, which was up to 4 weeks..
Reporting threshold: 0%.
Adverse-event reports describe events observed during the trial — not all are caused by the drug.
There are three components to this study: a Field Trial, a Shift Worker Survey, and Focus Groups. The Investigators will study the effectiveness, feasibility, and acceptability of an 8-h sleep intervention in older night workers in an operational environment. The overall goal of the Field Trial is to minimize sleep deficiency and negative outcomes resulting from that, including sleepiness and performance impairments during night shift work. The Shift Worker Survey is designed to understand some of the demographic and operational factors that enable or inhibit the ability of individual shift workers to adopt this intervention. The Focus Groups are designed to glean in-depth information from older shift workers who indicate that they are unable or unwilling to adopt an 8-h sleep timing intervention. Understanding these factors will assist in refining and targeting the intervention to those individuals who will be most likely to benefit from the intervention sleep timing strategy.
Publications & conference data
1 peer-reviewed publication reference this trial (live from Europe PMC):
Publications: Europe PMC API search by NCT ID, retrieved 10 June 2026
Drug + disease cross-links: matched in real time against Drug Landscape's normalised drug + company + condition tables
Sponsor: as reported to ClinicalTrials.gov by Brigham and Women's Hospital
Last refreshed: 15 August 2025
Drug Landscape aggregates and links these public records for informational use only. Always verify against the primary source before clinical or regulatory decisions. Canonical URL: https://druglandscape.com/trial/NCT03813654.