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

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: Completed
• Conditions: Healthy Volonteers
• Intervention / Treatment: Behavioral: On-duty Nap; Device: EndoPAT; Device: Popmeter®; Device: Panasonic EW3109; Device: ECG Holter; Other: Pichot fatigue scale; Other: French version of the Recovery Needs Scale (BRD); Other: The Short-Form 36 (SF-36); Other: Pittsburgh Sleep Quality Index (PSQI); Other: Epworth questionnaire; Other: The Karolinska Sleepiness Scale; Device: Actimeter; Behavioral: Control condition (30-min rest); Biological: Fasting blood sample

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

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

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
Evolution of reactive hyperemia index (RHI)	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

Outcome Measure	Measure Description	Time Frame
Evolution of pulse wave velocity (PWV)	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	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)	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	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	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	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	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	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	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	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	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	Fasting blood sample to measure NO, SOD, IL-18 initially and at 12 weeks.	Change between week 1 and 12
Evolution of sleep time	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

• Sponsor: Centre Hospitalier Universitaire de Saint Etienne
• Investigators: Principal Investigator: Frédéric ROCHE, MD PhD, Centre Hospitalier Universitaire de Saint Etienne

Study record dates

Study Major Dates

• Study Start (Actual): February 19, 2024
• Primary Completion (Actual): September 26, 2025
• Study Completion (Actual): December 22, 2025

Study Registration Dates

• First Submitted: June 23, 2023
• First Submitted That Met QC Criteria: July 19, 2023
• First Posted (Actual): July 21, 2023

Study Record Updates

• Last Update Posted (Actual): January 13, 2026
• Last Update Submitted That Met QC Criteria: January 12, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Endothelial function; Nurses; Nap; Shift work
• Additional Relevant MeSH Terms: Diagnostic Techniques and Procedures; Diagnosis; Diagnostic Techniques, Cardiovascular; Heart Function Tests; Electrodiagnosis; Monitoring, Physiologic; Electrocardiography; Monitoring, Ambulatory; Electrocardiography, Ambulatory; RE1-silencing transcription factor
• Other Study ID 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