Simulated Night Shift for Circadian Rhythm Disorder

(SPOTLIGHT Trial)

Overseen By Arpi Bocchieriyan, BS

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: University of Colorado, Denver

Must be taking: Oral contraceptives

Must not be taking: Antidepressants, Neuroleptics, Tranquilizers, others

Disqualifiers: Obesity, Smoking, Psychiatric disorders, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how working night shifts might affect bone health. Researchers aim to determine if short-term night shift work alters bone metabolism (the process of bone growth and breakdown) and if returning to normal sleep reverses these changes. Participants will follow either a regular sleep schedule or a simulated night shift schedule. This trial suits healthy adults who typically sleep 7-9 hours at night and are willing to adjust their sleep patterns for the study.

As an unphased study, this trial provides a unique opportunity to contribute to understanding the impact of sleep patterns on bone health.

Will I have to stop taking my current medications?

The trial requires participants to stop using medications that affect bone turnover or sleep, such as glucocorticoids, osteoporosis medications, and sleep medications, at least one month before the study. If you are on these medications, you may need to stop taking them to participate.

What prior data suggests that simulated short-term night shift work is safe?

Research shows that working night shifts can impact health in several ways. Studies have found that shift work can cause sleep problems, such as insomnia or excessive sleepiness, due to disruptions in the body's natural sleep-wake cycle, known as the circadian rhythm.

Evidence also indicates that working at night can increase the risk of mood problems, like depression, because it creates a mismatch between the body's internal clock and the external environment. Some research highlights that night shifts might lead to health concerns, such as a higher risk of car accidents during morning commutes and potential heart issues.

While these findings suggest risks, it's important to note that this study does not follow the usual clinical trial phases. Therefore, detailed safety data specific to this trial might not be available, as it primarily focuses on how night shifts might affect bone health. Thus, while some risks of night shift work are known, this particular study may not yet provide detailed safety results. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the simulated night shift work trial because it explores a novel approach to managing circadian rhythm disorders by mimicking real-world night shift conditions. Unlike traditional treatments that typically involve medication or light therapy to adjust sleep patterns, this method uses controlled sleep-wake cycles to potentially reset the biological clock naturally. The trial's design allows researchers to understand how structured sleep opportunities during atypical hours might influence circadian rhythms, providing insights that could lead to more effective, non-pharmacological interventions for individuals with disrupted sleep schedules.

What evidence suggests that simulated short-term night shift work could affect bone metabolism?

Research has shown that working night shifts can disrupt the body's natural internal clock, affecting sleep and health. In this trial, participants will undergo simulated night shift work to study these effects. Studies have found that night shift workers often struggle with sleep quality and experience increased daytime fatigue. This misalignment between work hours and the body's natural schedule can also lead to mood issues, such as depression. Additionally, working night shifts has been linked to higher risks of health problems, like heart issues, and a greater chance of accidents during morning commutes. These findings suggest that altered sleep patterns from night shift work might harm health by disrupting normal body functions. ^{1 3 5 6 7}

Who Is on the Research Team?

Christine M Swanson, MD, PhD

Principal Investigator

CU Anschutz

Are You a Good Fit for This Trial?

Healthy adults aged 20-40, who sleep 7-9 hours at night and are fully vaccinated against COVID-19. Women must be premenopausal, on oral contraception, not breastfeeding. Participants should commit to a study including inpatient stays and wear a wrist monitor for activity tracking.

Inclusion Criteria

I am a premenopausal woman not breastfeeding and on birth control pills.

Willing and able to complete a sleep diary, wear a wrist actigraphy monitor and complete a 3-6 week research study including two 4-night inpatient stays.

Willing and able to complete a sleep diary, wear a wrist actigraphy monitor and complete a 3-6 week research study including two 4-night inpatient stays

Exclusion Criteria

You have smoked within the past year.

Your bone density is very low compared to the average for your age and gender.

Your vitamin D level is less than 20 ng/mL.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline

Participants undergo baseline measurements and sleep under normal conditions

1 night

Inpatient stay

Simulated Night Shift Work

Participants experience simulated night shift work with 3-hour afternoon naps and 12-hour night shifts

3 nights

Inpatient stay

Follow-up

Participants are monitored for changes in bone turnover markers after resuming normal sleep patterns

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Simulated short term night shift work

Trial Overview

The trial is testing how simulated night shift work affects bone metabolism by measuring bone turnover markers and sympathetic nervous system tone. It involves two sets of four-night inpatient stays with follow-up to see if normal patterns reverse any changes.

How Is the Trial Designed?

Group I: Simulated Night Shift Work Experimental Treatment 1 Intervention

Two inpatient stays, each involving a baseline night, followed by a 3-hour afternoon nap opportunity, and then three 12-hour night shifts, with 8-hour daytime sleep opportunity in between.

Group II: Control (8 hours nocturnal sleep) Active Control 1 Intervention

Inpatient protocol involves 8-hour sleep opportunity during the biological night throughout.

Who Is Running the Clinical Trial?

University of Colorado, Denver

Lead Sponsor

Trials

1,842

Recruited

3,028,000+

National Heart, Lung, and Blood Institute (NHLBI)

Collaborator

Trials

3,987

Recruited

47,860,000+

Published Research Related to This Trial

Shift work disorder affects 15 to 25% of the U.S. labor force, leading to significant disruptions in sleep patterns and overall health due to misalignment with the body's circadian rhythm.

Clinicians require better understanding of the circadian rhythm's impact on human functioning and the consequences of shift work disorder to improve diagnosis and treatment in affected individuals.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

How the circadian rhythm affects sleep, wakefulness, and overall health: background for understanding shift work disorder. Krystal, AD.[2012]

In a study involving 86 shift-worker nurses, taking 5 mg of melatonin 30 minutes before sleep significantly reduced the time it took to fall asleep compared to a placebo.

Melatonin did not affect the total sleep time and was found to have no adverse effects, suggesting it is a safe and effective option for improving sleep onset in night shift workers.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy and hypnotic effects of melatonin in shift-work nurses: double-blind, placebo-controlled crossover trial. Sadeghniiat-Haghighi, K., Aminian, O., Pouryaghoub, G., et al.[2020]

Exposure to daylight when night shift nurses drive home can disrupt their circadian rhythms, leading to increased health risks and decreased job performance.

Shifts from 3:00 a.m. to 3:00 p.m. and 3:00 p.m. to 3:00 a.m. are associated with less physiological and emotional stress, suggesting that awareness and management of circadian rhythms could improve nurses' health and patient care quality.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Understanding circadian rhythms: a holistic approach to nurses and shift work. Efinger, J., Nelson, LC., Starr, JM.[2018]

A study of 59 Italian orthopaedic nurses revealed that those working night shifts had significantly lower rest-activity circadian rhythm amplitudes compared to day shift nurses, indicating disrupted circadian rhythms (p < 0.001).

Both normal weight and overweight night shift nurses exhibited reduced amplitude in their circadian rhythms during work hours, suggesting that shift work negatively impacts health regardless of body weight (p < 0.01 for normal weight and p < 0.001 for overweight).

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effects of Shift Work in a Sample of Italian Nurses: Analysis of Rest-Activity Circadian Rhythm. Galasso, L., Mulè, A., Castelli, L., et al.[2021]

A study on simulated shift work showed that adjusting sleep/dark schedules can help shift workers adapt by inducing phase shifts in their circadian rhythms, although these shifts may not fully align with night shift demands.

The findings suggest that while scheduled sleep can improve adaptation for night shift workers, the extent of the phase shifts achieved may still leave some workers struggling with sleep quality and timing.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Scheduling of sleep/darkness affects the circadian phase of night shift workers. Santhi, N., Duffy, JF., Horowitz, TS., et al.[2013]

A systematic review of 68 studies on interventions for shiftworkers found that only 60.3% assessed implementation, highlighting a gap in understanding how these interventions are applied in real-world settings.

The average quality of implementation assessment was moderate (2.56 out of 5), and only a small number of studies identified enablers (25%) or barriers (26.5%) to effective implementation, suggesting that future research should focus more on these aspects to improve intervention effectiveness.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Implementation of interventions designed to promote healthy sleep and circadian rhythms in shiftworkers. Harrison, EM., Schmied, EA., Yablonsky, AM., et al.[2021]

Frequent shift rotation in employment can lead to specific sleep disorders, particularly Delayed Sleep Phase (DSP) insomnia, which disrupts circadian rhythms and impairs daily functions.

Shift work can also result in excessive daytime sleepiness disorders, such as narcolepsy, highlighting the need for clinicians to consider the impact of disrupted sleep-waking schedules on their patients.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Circadian rhythm disturbances and sleep disorders in shift workers. Guilleminault, C., Czeisler, C., Coleman, R., et al.[2015]

Shift workers, particularly those with an evening chronotype, are at a higher risk for developing obesity and other chronic health issues due to circadian misalignment, even when accounting for short sleep duration.

This review of 21 studies highlights the need for further research on how aligning shift work schedules with individual chronotypes could improve health outcomes for shift workers, suggesting potential strategies for occupational health interventions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Identifying shift worker chronotype: implications for health. Hittle, BM., Gillespie, GL.[2019]

Hospitalists working night shifts face challenges due to misalignment with their natural circadian rhythms, leading to sleep deprivation and increased risk of medical errors.

Implementing circadian adaptation strategies, such as improving sleep hygiene, using caffeine, and exposure to bright light, can help mitigate fatigue and enhance safety for hospitalists, but further research is needed to optimize scheduling and performance.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Sleep and circadian misalignment for the hospitalist: a review. Schaefer, EW., Williams, MV., Zee, PC.[2015]

Night shift workers often struggle to adjust their circadian rhythms, which can negatively impact their health and safety; this paper reviews studies that used artificial light to help shift these rhythms for better adaptation.

The authors provide fundamental principles and a specific example of a light/dark schedule that can help night shift workers align their circadian rhythms with their unusual work hours, potentially improving their quality of life.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

How to use light and dark to produce circadian adaptation to night shift work. Eastman, CI., Martin, SK.[2019]

Working multiple consecutive night shifts significantly increases the risk of crashes during the morning commute, with crash likelihood being 11 times higher at the start of the week compared to pre-work commutes.

Although crash risk is highest at the beginning of the week, it decreases over the course of the week, indicating that fatigue effects may lessen as the body adjusts to the night shift schedule.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The likelihood of crashing during a simulated post-work commute decreases across a week of consecutive night shifts. Roach, GD., Sach, EJ., Reiter, AM., et al.[2021]

Shift work affects nearly 20% of the global labor force and is linked to negative impacts on worker health, safety, and quality of life due to disruptions in circadian rhythms and increased sleepiness during shifts.

Management strategies for shift work disorder (SWD) include promoting better sleep and wakefulness, but more research is needed to understand the health risks and develop effective treatments for those affected.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Shift work and the assessment and management of shift work disorder (SWD). Wright, KP., Bogan, RK., Wyatt, JK.[2022]

Shift work affects 15-30% of adult workers, leading to a condition known as shift work sleep disorder, which can cause excessive sleepiness and sleep disruption in 2-5% of these workers.

The disorder significantly impacts worker safety and performance, increasing the risk of accidents and impairing health, particularly during night shifts when sleepiness is at its peak.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Impacts of shift work on sleep and circadian rhythms. Boivin, DB., Boudreau, P.[2022]

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Simulated night-shift experiments and field-based studies with shift workers both indicate that the circadian system is resistant to adaptation from a day- to a ...

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pmc.ncbi.nlm.nih.gov/articles/PMC6859247/

Shift Work and Shift Work Sleep Disorder - PubMed Central

A substantial percentage of shift workers develop shift work disorder, a circadian rhythm sleep disorder characterized by excessive sleepiness, insomnia, or ...

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Night shift work can associate with an increased risk for depression. As night workers experience a 'misalignment' between their circadian ...

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Circadian adaptation to night shift work is associated with ...

This study has demonstrated that REM sleep duration during a daytime recovery sleep episode was significantly longer in night shift workers ...

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withpower.com

withpower.com/trial/phase-bone-diseases-metabolic-2022-b1b0b

Simulated Night Shift for Circadian Rhythm Disorder

Simulated night shift work can lead to increased crash risk during morning commutes, disturbed sleep, and health issues like cardiovascular risk and sleep ...

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NCT05074277 | Skeletal Response to Simulated Night Shift

This small intervention study will determine if simulated short-term night shift work (NSW) negatively alters bone metabolism.

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sciencedirect.com/science/article/pii/S2352721823002012

Circadian adaptation to night shift work is associated with ...

Partial circadian adaptation to night shift was associated with longer rapid eye movement sleep duration during daytime sleep.