Effect of a Short Nap During the Night Shift of Healthcare Workers on Endothelial Function (NAP-WORK)

January 12, 2026 updated by: Centre Hospitalier Universitaire de Saint Etienne

Effect of a Short Nap During the Night Shift of Healthcare Workers on Endothelial Function: NAP-WORK Randomized Controlled Study

Night shift work is well known to cause health disruption in short and long term. It has been reported that among healthcare workers, nurses slept less than 6 h/24h. Consequences of such short sleep duration has been associated to long term issues such as endothelial dysfunction associated with cardiovascular diseases, arterial hypertension and type 2 diabetes. Countermeasures such as nap at work has potential effects on reducing the prevalence of cardiovascular diseases. However, to our knowledge, no studies have objectively investigated the effects of napping on endothelial function in a longitudinal design. Therefore, this study aims to investigate the effect of a 30 minutes on-duty nap during night work for 12 weeks on caregivers endothelial dysfunction.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • France
      • Saint-Etienne, France, 42055
        • CHU de Saint-Etienne

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Being a paramedical caregiverr (nurse or care assistant) at Saint-Etienne University Hospital
  • Be aAged between 18 and 65
  • Working at least 80% of a full-time equivalent post
  • Working 12-hour shifts (day/night) in continuous care services
  • Being affiliated or entitled under a social security scheme
  • Havinge received informed information about the study and have co-signed, with the investigator, a consent to participate in the study

Exclusion Criteria:

  • Have made a tTrans meridian journey in the last month prior to the study
  • Have a mMedically diagnosed sleep disorder such asof the hypersomnia or insomnia type
  • Have a diagnosed and treated mental pathology
  • Usually take a nap in the workplace in a quiet room
  • Be pregnant or breastfeeding
  • Have medically diagnosed neurovascular or neuromuscular pathologies

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Nap group
The experimental group will be allocated to do a 30-min on-duty nap during night work, in a dedicated room between 1 am and 4 am.
Behavioral: On-duty Nap
For 12 weeks, an opportunity for a 30-minute nap during the night shift, between 1 a.m. and 4 a.m., in a quiet room with facilities for lying down.
Device: EndoPAT

The EndoPAT device® measures vascular reactivity after a 5-minute occlusion on one arm.

This device measures changes in vascular tone induced by the endothelium at fingertip level using a pair of plethysmographic sensors. The measurement consists of performing a reference recording for 5 minutes on the 2 arms, then a test arm is chosen to perform an occlusion for 5 minutes while continuing the recording.

Device: Popmeter®
The tool is connected to the caregiver's finger and toe via photodiode sensors. Its simple operation enables reproducible measurement of the propagation speed of the pulse wave in 14 seconds.
Device: Panasonic EW3109
Diastolic and systolic blood pressure measured 3 times in succession using an automatic blood pressure monitor (Panasonic EW3109) in the sitting position on the left arm.
Other Names:
  • automatic blood pressure device
Device: ECG Holter
The Holter takes an ECG during the subject's daily activities at home.
Other Names:
  • portable electrocardiogram
Other: Pichot fatigue scale
The Pichot fatigue scale is an 8-item questionnaire, with a score above 22 indicating excessive fatigue.
Other: French version of the Recovery Needs Scale (BRD)
BRD questionnaire consists of 11 items coded 0 or 1. A score is calculated for each participant, multiplied by 10 to give a score ranging from 0 to 100. The greater the need for recovery, the higher the score.
Other: The Short-Form 36 (SF-36)
The SF-36 questionnaire is used to assess quality of life. It comprises 8 sub-scores ranging from 0 (minimum quality of life) to 100 (maximum well-being).
Other: Pittsburgh Sleep Quality Index (PSQI)
24-question sleep quality assessment scale, a score > 5 indicates poor sleep quality
Other: Epworth questionnaire
8-question sleepiness assessment scale, a score above 10 indicates excessive sleepiness
Other: The Karolinska Sleepiness Scale
The Karolinska Sleepiness Scale measures daytime sleepiness on a 9-point scale, based on 5 states and 4 intermediate states that are not verbally indicated.
Device: Actimeter
An actimeter will be worn on the non-dominant wrist, uninterrupted day and night, for 7 consecutive days.
Biological: Fasting blood sample
15 ml blood sample (venous sampling) will be taken to measure inflammatory biomarkers (hsCRP, IL-6 TNF-α, IL-1β) and blood markers of endothelial function (NO, CRP, SOD, IL-18).
Active Comparator: Control group
The control group will be allocated to rest in a dedicated room without napping between 1 am and 4 am.
Device: EndoPAT

The EndoPAT device® measures vascular reactivity after a 5-minute occlusion on one arm.

This device measures changes in vascular tone induced by the endothelium at fingertip level using a pair of plethysmographic sensors. The measurement consists of performing a reference recording for 5 minutes on the 2 arms, then a test arm is chosen to perform an occlusion for 5 minutes while continuing the recording.

Device: Popmeter®
The tool is connected to the caregiver's finger and toe via photodiode sensors. Its simple operation enables reproducible measurement of the propagation speed of the pulse wave in 14 seconds.
Device: Panasonic EW3109
Diastolic and systolic blood pressure measured 3 times in succession using an automatic blood pressure monitor (Panasonic EW3109) in the sitting position on the left arm.
Other Names:
  • automatic blood pressure device
Device: ECG Holter
The Holter takes an ECG during the subject's daily activities at home.
Other Names:
  • portable electrocardiogram
Other: Pichot fatigue scale
The Pichot fatigue scale is an 8-item questionnaire, with a score above 22 indicating excessive fatigue.
Other: French version of the Recovery Needs Scale (BRD)
BRD questionnaire consists of 11 items coded 0 or 1. A score is calculated for each participant, multiplied by 10 to give a score ranging from 0 to 100. The greater the need for recovery, the higher the score.
Other: The Short-Form 36 (SF-36)
The SF-36 questionnaire is used to assess quality of life. It comprises 8 sub-scores ranging from 0 (minimum quality of life) to 100 (maximum well-being).
Other: Pittsburgh Sleep Quality Index (PSQI)
24-question sleep quality assessment scale, a score > 5 indicates poor sleep quality
Other: Epworth questionnaire
8-question sleepiness assessment scale, a score above 10 indicates excessive sleepiness
Other: The Karolinska Sleepiness Scale
The Karolinska Sleepiness Scale measures daytime sleepiness on a 9-point scale, based on 5 states and 4 intermediate states that are not verbally indicated.
Device: Actimeter
An actimeter will be worn on the non-dominant wrist, uninterrupted day and night, for 7 consecutive days.
Behavioral: Control condition (30-min rest)
For 12 weeks, an opportunity for a 30-minute rest during the night shift, between 1 a.m. and 4 a.m., in a quiet room without facilities for lying down or napping.
Biological: Fasting blood sample
15 ml blood sample (venous sampling) will be taken to measure inflammatory biomarkers (hsCRP, IL-6 TNF-α, IL-1β) and blood markers of endothelial function (NO, CRP, SOD, IL-18).

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Evolution of reactive hyperemia index (RHI)
Time Frame: Change between week 1 and 12
RHI is measured through the EndoPAT device® initially and at 12 weeks, and corresponds to the vascular reactivity following a 5-min occlusion on an arm
Change between week 1 and 12

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Evolution of pulse wave velocity (PWV)
Time Frame: Change between week 1 and 12
PWV is measured through the Popmeter® initially and at 12 weeks, and corresponds to the finger-o-foot pulse wave velocity(m/s)
Change between week 1 and 12
Evolution of blood pressure
Time Frame: Change between week 1 and 12
Systolic and diastolic blood pressure (mm Hg) measured in the sitting position in triplicate with an automatic blood pressure device (Panasonic EW3109) on the left arm, initially and at 12 weeks.
Change between week 1 and 12
Evolution of heart rate variability (HRV)
Time Frame: Change between week 1 and 12
24-h Holter-Electrocardiogram to derive temporal (SDNN, rMSSD, pNN50) and frequency (LF, HF, LF/HF) HRV indices initially and at 12 weeks.
Change between week 1 and 12
Evolution of subjective Fatigue
Time Frame: Change between week 1 and 12
The Pichot fatigue scale (composed of 8 items, a score above 22 indicates excessive fatigue), initially and at 12 weeks.
Change between week 1 and 12
Evolution of recovery Needs
Time Frame: Change between week 1 and 12
French version of the Recovery Needs Scale (BRD), initially and at 12 weeks, wich consists of 11 items coded 0 or 1. A score is calculated for each participant, multiplied by 10 to give a score ranging from 0 to 100. The greater the need for recovery, the higher the score.
Change between week 1 and 12
Evolution of state of health
Time Frame: Change between week 1 and 12
The SF-36 questionnaire is used to assess quality of life, initially and at 12 weeks. It comprises 8 sub-scores ranging from 0 (minimum quality of life) to 100 (maximum well-being).
Change between week 1 and 12
Evolution of sleep quality
Time Frame: Change between week 1 and 12
Pittsburgh Sleep Quality Index (PSQI), initially and at 12 weeks : 24-question sleep quality assessment scale, a score > 5 indicates poor sleep quality.
Change between week 1 and 12
Evolution of subjective sleepiness
Time Frame: Change between week 1 and 12
Epworth questionnaire, initially and at 12 weeks : 8-question sleepiness assessment scale, a score above 10 indicates excessive sleepiness
Change between week 1 and 12
Evolution of alertness at work assessed
Time Frame: Change between week 1 and 12
The Karolinska Sleepiness Scale measures daytime sleepiness on a 9-point scale, based on 5 states and 4 intermediate states that are not verbally indicated, initially and at 12 weeks.
Change between week 1 and 12
Evolution of sleep duration
Time Frame: Change between week 1 and 12
Actimeter measuring variations in wake-up and bedtimes, sleep duration, energy expenditure and time spent at different levels of physical activity intensity (sedentary, light intensity, moderate to intense intensity), initially and at 12 weeks.
Change between week 1 and 12
Evolution of pro-inflammatory biomarkers
Time Frame: Change between week 1 and 12
Fasting blood sample to measure hsCRP, IL-6 TNF-α, IL-1β initially and at 12 weeks.
Change between week 1 and 12
Evolution of blood markers of endothelial function
Time Frame: Change between week 1 and 12
Fasting blood sample to measure NO, SOD, IL-18 initially and at 12 weeks.
Change between week 1 and 12
Evolution of sleep time
Time Frame: Change between week 1 and 12
Actimeter measuring variations in wake-up and bedtimes, sleep duration, energy expenditure and time spent at different levels of physical activity intensity (sedentary, light intensity, moderate to intense intensity), initially and at 12 weeks.
Change between week 1 and 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Centre Hospitalier Universitaire de Saint Etienne

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Frédéric ROCHE, MD PhD, Centre Hospitalier Universitaire de Saint Etienne

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 19, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 26, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 22, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 23, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
July 19, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 21, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 13, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 12, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 23CH138
  • 2023-A01109-36 (Other Identifier: ANSM)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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