Table 1.

Characteristics of Experimental and Quasi-experimental Studies Examining Sleep Interventions in Nurses

Source Country	Population Subjects (N) Women (%)	Mean Age (yr)	Intervention Duration (Follow-up)	Intervention	Control	Main Sleep-related Outcomes	Additional Outcomes	Conclusion on Main Sleep-related Outcomes (Comparison with control)
Experimental
Aroma Therapy
Chang, 2017 Taiwan	Nurses on monthly rotating nights shifts 50 100%	29	4 wks (weekly follow up)	An aroma therapy massage with music (25 min massage +35 min rest), once a week for 4 wks	Lay down with music (60 min rest), once a week for 4 wks	PSQI total and subscale scores	Take-home sleep detector, Ezsleep	There were no differences in PSQI total score, but a significant improvement in sleep quality at post-intervention in the intervention group compared to the control group. There were significant improvements in PSQI total score, subjective sleep quality, sleep disturbance, and daytime dysfunction in the intervention group compared to baseline.
Hsu, 2021 Taiwan	ER and ICU nurses 103 92.7%	31	4 wks (4 wk & 8-wk follow up)	50-min lavender essential oil massage with music, once a week for 4 wks	None	PSQI-Chinese total score	Actigraphy, HRV, OBI-Chinese	There were no differences between the intervention and control group on PSQI total score at post-intervention and 8-wk follow up. For the intervention group, the self-reported PSQI score revealed an improvement at post-intervention and 8-wk follow-up compared to baseline.
Nasiri, 2021 Iran	Nurses on rotating shifts 80 88.8%	29	2 hrs in a typical night shift	Wear a fabric (surgical) mask with a drop of rosemary essential for 5–10 mins followed by 10–15 mins removal, repeatedly for 2 hours	Wear a fabric mask with a drop of distilled water for 5–10 mins followed by 10–15 mins removal, repeatedly for 2 hours	KSS, ESS	None	Compared to the control group, intervention group had significantly decreased sleepiness and increased alertness at post-intervention.
Dietary Supplements
Baradari, 2018 Iran	ICU nurses 53 92.5%	31	1 mon	220 mg zinc sulfate capsules every 72 hours for 1 month	Placebo every 72 hours for 1 month	PSQI total score and subscale scores	Serum zinc level	There were significantly improved PSQI total scores and subjective sleep quality scores at the post-intervention in the intervention group compared to the control group.
Mousavi, 2020 Iran	Nurses with significant fatigue 105 88%	35	4 wks	100 mg CoQ10 capsule twice daily	Placebo twice daily	PSQI total score	Fatigue score on Nurse’s Fatigue Scale	There was significantly improved PSQI total score in the intervention group compared to the baseline and the control group.
Zhang, 2020 China	Nurses on a rotating three-shift schedule 38 100%	29	1 mon	10 g Shimian granules twice daily for 1 month, plus sleep hygiene education	Placebo twice daily for 1 month, plus sleep hygiene education	ISI one day before initial treatment and 1 day after last treatment	PVT, HADS, HADS-A, and HADS-D one day before initial treatment and 1 day after last treatment, salivary melatonin and proinflammatory cytokine at bedtime every 7 days	There were significant decreases in insomnia severity at post-intervention in the intervention group compared to the control group.
Cognitive Behavioral Therapy
Dahlgren, 2022 Sweden	Nurses with less than 12 months’ work experience 207 88%	27	4 wks (6-mon follow-up)	Three 2.5hr group-based proactive recovery program sessions based on CBT and motivational interviewing techniques	Waitlist control – usual care and then receive the intervention after follow-up	ISI, KSQ	SMBQ, WIPL, Somatic Symptom Scale-8, PSS, DBAS-10	There were no significant differences in ISI or KSQ between the two groups at post-intervention and follow-up.
Zhou, 2022 China	Nurses with chronic insomnia 118 98%	30	6 wks	e-aid CBT-I	None	PSQI, ISI	GAD-7, PHQ-9	There were significant improvements in sleep quality and insomnia severity in the intervention group compared to the control group and baseline.
Light Therapy
Tanaka, 2011 Japan	Nurses working rapid day-night rotating shifts 61 100%	30	1 mon	10-min morning bright light exposure using bright light device in the workplace before 7:30am for all day-shift workdays	Crossover control – usual care then receives the intervention after one week washout period	KSS, night sleep by 0–10 VAS	CIS, RT, and number of lapses by PVT, frequency of perceived adverse events and near misses	There were significant improvements on sleepiness and night sleep for day-shift days in intervention periods compared to control periods.
Huang, 2013 Taiwan	Nurses with high ISI score, working three-shift rotation 92 100%	30	At least 10 days during 2 wks	Exposure to bright light for ≥ 30 mins during the first half of the evening/night shift and wearing dark sunglasses after shift	No exposure to bright light, but wearing dark sunglasses after shift	ISI	HADS	The ISI score was significantly improved in the intervention group compared to the control group and the baseline.
Rahman, 2013 Canada	12-hr day or night shift nurses 9 56%	31	8-wk randomized crossover design	Wearing glasses fitted with short-wavelength filters during night shifts	Receiving standard indoor light during night shifts	PSG, sleep diary	Saliva melatonin assays, subjective and objective alertness (self-report scale and PDA), CES-D, ESS	There were significant increases in TST and SE and decreases in WASO in the intervention group compared to the control group for nighttime sleep, but no significant differences between groups for daytime sleep.
Griepentrog, 2018 U.S.	Night shift ICU nurses 43 71%	29	One night shift, cross-over	10-hr exposure to high illuminance white light	10-hr exposure to standard ambient fluorescent lighting	SSS	Number of lapses and errors on PVT, PVT median response time, salivary melatonin concentration	There was a significant reduction of SSS score at the end of the night shift in the intervention group compared to the control group.
Bjorvatn, 2021 Norway	Nurses working at least three consecutive night shifts 35 80%	35	Three consecutive night shifts, counter-balanced randomized cross-over	Sit in front of a bright light box for 30 mins at each night shift, the timing of light exposure was delayed by one hour at each following night shift	Sit in front of a red dim light box for 30 mins at each night shift, the timing of light exposure was delayed by one hour at each following night shift	ATS, KSS	PVT, mood and energy, caffeine intake	Heavy eyelids significantly reduced during the night shifts in the experimental condition compared to the placebo condition. No differences in sleepiness between the two conditions during or after the night shifts.
Cyr, 2023 Canada	Nurses during COVID working rapid rotating schedules with consecutive night shifts 57 84%	31	20 days	Evening light exposure, with suggestions on staying up 1 hr later on the night before first night shift, sleep using a provided 3D eye mask, wear dark sunglasses in the morning, optionally nap in the late afternoon, and expose to 40-min bright light at home before night shifts.	Chrononutrition control, with suggestions on the timing and content of meals and snacks	KSS, Sleep Quality Scale, sleep and wake time	Fatigue, work-related errors, mood	There were significant improvements in sleepiness and fatigue, but only minor changes in sleep duration, in the intervention group compared to the baseline. There were no differences between the intervention and control group in any sleep outcomes.
Mind Body Therapy
Fang, 2015 China	Nurses 105 100%	35	6 mons	Coached group yoga sessions, 50–60 min per session, more than 2 sessions per week	None	PSQI total score and subscale scores	QMWS	There were significantly improved PSQI total score, subjective sleep quality, sleep duration and sleep efficiency score, and less sleep disturbances, less use of sleep medication and less daytime dysfunction in the intervention group compared to the control group.
Nourian, 2021 Iran	COVID first-line nurses 41 87.7%	36	7 wks	Online MSBR program delivered through Whats App Messenger including meditation audio, yoga video readings about the nature of mindfulness and audio or video of speeches related to mind exercises	None	PSQI total score and subscale scores	None	There were significantly improved subjective sleep quality and sleep latency scores in the intervention group compared to the control group and the baseline. There was also significantly improved sleep efficiency in the intervention group compared to the baseline.
Çelik, 2023 Turkey	Nurses during COVID pandemic 90 87%	29	4 wks	40-min laugher yoga evening sessions twice each week including deep breathing exercises, warm-up exercises, childish games, and laugher exercises.	Usual care (offered the intervention after post-test)	PSQI	CD-RISC	There was significantly improved PSQI total score in the intervention group compared to the control group and the baseline.
Sleep Education
Yazdi, 2017 Iran	Shift work nurses with clinical insomnia 100 100%	30	1 mon	2-hr training and a brochure about sleep hygiene practices	A brochure about sleep hygiene practices	ISI, ESS, PSQI total score and subscale scores	None	There was significantly improved ISI, ESS, and PSQI, bedtime at night, sleep latency, frequency of unwanted napping during the day, and subjective sleep quality, sleep duration, sleep efficiency, and sleep disturbances at one-month post-intervention in the intervention group compared to the control group.
Exercise
Niu, 2021 Taiwan	Shift work nurses with baseline PSQI>5 60 100%	26	8 wks (4-wk, 8-wk, and 12-wk data collection)	Moderate-intensity aerobic exercise program including indoor treadmill walking and jogging under a rehab instructor’s supervision for 8 wks with 60 min per session and 5 times per week	Usual activity without regular exercise	Actigraphy TST, SL, WASO, SE	None	The intervention group showed improved TST and SE at 4-wk and 8-wk compared to baseline. The improvement in TST continued until 12-wk. There were significantly improved SL and WASO at 4-wk in the intervention group compared to the control group.
Multicomponent Intervention
Yoon, 2002 Korea	Rotating night-shift nurses with backward rotation 12 100%	Range 23–27	2 days of 4-day night shifts	Mel Group: 6 mg melatonin before daytime sleep with morning sunlight permitted Mel-S Group: 6 mg melatonin before daytime sleep with sunglasses worn to attenuate morning sunlight	Placebo before daytime sleep with morning sunlight permitted	TST, SL, SE, SPT by sleep log	VAS for nocturnal alertness, DS-CPT, POMS	There were significant increases in sleep period and total sleep time by melatonin treatment (Mel and Mel-S) compared to placebo, but no differences in sleep period and total sleep time between Mel and Mel-S, and no differences in SL and SE among the three groups.
Booker, 2022 Australia	Nurses on regular rotating or permanent night shifts 149 96%	35	Education duration is not specified, 4 one-on-one coaching sessions over 8 weeks	Sleep and shift work education, plus coaching sessions with individualized strategies on home-based activities such as napping and scheduled sleep, light exposure during work, caffeine consumption, sleep hygiene practice and melatonin (clustered randomization)	Low glycemic index diet education, plus home-based activities such as food diary and taking low glycemic index foods	SWD, SHI, ISI, FOSQ-10	Ward-based sick leave, ASTNQ, MEQ, PHQ-9, GAD-7	There were no significant differences in sleep outcomes between the intervention and control group. There were significantly improved ISI and FOSQ-10 scores in the intervention group compared to baseline, but no differences in SWD and SHI.
Hausswirth, 2022 France	Nursing staff during COVID pandemic 45 78%	44	4 wks	Rebalance© Impulse, a light stimulation and mindfulness training device, 30 min per session, 2–3 sessions per week for a total of 10 sessions	None	Actigraphy, sleep diary, perceived sleep quality, SSQ, FIRST	BP, HR, HRV, blood cortisol and alpha-amylase concentration	SSQ, perceived sleep quality, sleep efficiency, and fragmentation index significantly improved in the intervention group compared to the control group.
Source Country	Population Subjects (N) Women (%)	Mean Age (yr)	Intervention Duration (Follow-up)	Intervention	Control	Outcomes related to Sleep	Additional Outcomes	Main Conclusion (Comparison with control)
Quasi-experimental
Aroma Therapy
Seo, 2017 Korea	Nurses on three-shift working 60 No report of women%	>30 (72%)  ≤30 (28%)	2 wks	Dropping aroma oil to pillows every day before going to bed	No description	Self-report sleep quality	Self-report fatigue	There were significant differences in overall sleep quality at post-intervention in the intervention group compared to the control group. These differences were also observed on insufficient sleep, difficulty in falling asleep, difficulty in lying awake, sleep satisfaction, and difficulty in maintaining sleep.
Dietary Supplement
Franco, 2012 Spain	Nursing staff having at least one night shift per week  17  100%	41	2 wks	Ingest 330 mL alcohol-free beer (containing the hop, humulus lupulus L.) daily with supper	Control week not receiving the alcohol-free beer with supper (within subjects)	Actigraphy TIB, TST, SL, SE, total activity pulses during sleep	Work stress, STAI	There were significant decreases in Actigraphy sleep latency and total activity pulses during sleep after the intervention, but no significant differences in total sleep time and sleep efficiency.
Cognitive Behavioral Therapy
Carter, 2013 U.S.	Hospice nurses 9 89%	54	Twice, at wk 2 and wk 4 (wk 3 and wk 5 data collection)	Two 1-hr group education intervention sessions about CBT-I	No control	PSQI	CES-D	There were no significant changes at post-intervention.
Lee, 2014 U.S.	Night shift nurses 21 95%	46	4 wks (8-wk follow-up)	4-wk active control intervention including a sleep diary and weekly readings from a booklet about shift work and sleep; and 4-wk SETS-SW intervention including a sleep diary and a home-based cognitive behavioral therapy	No control	PSQI, GSDS, 7 days of wrist actigraphy	CES-D, SSI	There are significant improvements on subjective PSQI and GSDS scores after the SETS-SW intervention. Subscale scores of sleep quality, onset latency, and daytime sleepiness were significantly improved after the intervention, but no significant change in objective sleep parameters assessed by actigraphy.
Omeogu, 2020 U.S.	Day shift nurses 13 100%	52	6 wks (both 3-wk and 6-wk data collection)	CBT-I Coach app on cellphone	No control	ISI	None	There was significant decrease on ISI score at 3 week and the trend sustained at 6 week, with 24% attrition rate.
Light Therapy
Boivin, 2012 Canada	8-hr night shift nurses 17 59%	42	An average of 12 night shifts over an average of 19 days	Intermittent exposure to full-spectrum bright light during the first 6h of each night shift and wearing shaded goggles during the 2 h following the end of the night shift including the commute home plus remaining in bed for 8h	Usual habitual light environment at work and wearing clear UV-excluding goggles for the morning commute home	TST, SO, SE by Nightcap device or portable PSG	Core body temperature, melatonin markers, saliva melatonin levels	There was significant more TST (~30 mins) for daytime sleep after night shifts in the intervention group compared to the control group, but no significant differences in SO and SE.
Jensen, 2016 Denmark	Evening/night shift ICU nursing staff 113 No report of women%	42/43	10 days with at least two evening/night shifts in a row and 2 dayshifts/days off in a row	Designated dynamic light at work	Ordinary institutional light at work	Actigraphy SE & WASO, subjective sleep quality from sleep diary	Saliva melatonin levels, subjective well-being and health	There were no significant differences in Actigraphy SE and WASO, but better self-reported sleep quality after night shifts at post-intervention between the intervention and control groups. Actigraphy showed the control group had 16% more awakenings than the intervention group.
Aarts, 2020 Netherlands	Rapid rotating night shift nurses 23 87%	30	Three consecutive night shifts (a total of 7-days data collection)	Wearing a light therapy glass with integrated LEDs for 4*15 min during 3 night shifts, for 30 min within 2 h after awakening, and wearing the orange-tinted blue-blocking goggles during the morning commute home	Wearing a placebo glass during 3 night shifts and for 30 min within 2 h after awakening, and wearing the orange-tinted blue-blocking goggles during the morning commute home	KSS, DSS, Actigraphy BT, GUT, TIB, TST, SL, SE, FI, and subjective GSQS	Person-bound light exposure, perceived effectiveness	There was no significant difference in sleepiness, but significantly lower sleepiness on commute home after the first night shift, significantly better sleep on the second recovery day, and significantly better subjective sleep quality after the first night shift in the intervention group compared to the control group.
Hoshi, 2022 Japan	Rotating and regular night shift nurses 17 100%	35	2 wks	Dark room lightening with 110 lx on the desk at the nurse station (within subjects)	Well-lit condition with 410 lx on the desk and ceiling lights	Qguri-Shirakawa-Azumi Sleep Inventory; sleepiness	Fatigue, malpractice/incidents/accidents	There was no significant difference of sleep quality, but increased drowsiness or lethargy on certain shifts in dark conditions compared to well-lit conditions.
Mind Body Therapy
Liu, 2021 China	COVID first-line nurses 140 93.6%	32	4 wks	Nurses were provided the DBRT information guide, MP3 audio recording, demonstration video, and self-training record and required to complete the DBRT at 8pm daily.	No control	PSQI-Chinese total score and subscale scores	SAS-Chinese, SDS-Chinese	There were significantly improved PSQI total score, subjective sleep quality, sleep duration and sleep efficiency score, less sleep disturbances, less daytime dysfunction compared to the baseline.
Parajuli, 2021 India	Nursing staff 33 100%	41	4 wks	Group yoga for 45 min/day, 5 days/week	No control	PSQI total score	PSS	There was significantly improved PSQI score compared to the baseline.
Sleep Education
Morimoto, 2016 Japan	Nurses 25 88%	40	2 wks	SHT: Two 90-min sleep education workshops on sleep hygiene education and relaxation techniques	Two 90-min sleep education workshops only	PSQI-Japanese total score and subscale scores, ESS-Japanese,	PHQ-Japanese, MBI-Japanese, SF-8 Health Survey-Japanese	There were significantly improved PSQI total score and daytime dysfunction score at post-intervention in the intervention group compared to the control group. Participants with sleep problems in the intervention group showed significant improvements in sleep latency, sleep disturbance, and sleepiness scores than those in the control group.
Nap
Zion, 2019 Israel	Nurses working irregular rotating shifts including night shifts 110 100%	39	4 nights	Two nights with a scheduled 30-min nap at 4am	Two nights without a scheduled nap (within subjects)	KSS	DSST, LCT, MCTQShift	Lower sleepiness was observed at 5am, 6am and 7am on nights with a nap compared to nights without a nap.
Shift Schedule Intervention
Kubo, 2022 Japan	Nurses in a cardiac surgery unit working three-shift schedule with backward rotation 30 No report of women%	28	2 mons	Shift-work schedule change to add one day off after every two consecutive night shifts	Non-randomized crossover control – usual care then receives the intervention afterwards	TST, SL, SE, WASO by sleep mattress sensors, total sleep hours, mean sleep duration, number of sleep opportunities by sleep log, sleep quality, and sleepiness	PVT, CRP, MQ, REQ, KPDS, UWES, fatigue, stress, quality of care, satisfaction with days off, work satisfaction	There were significant improvements in total sleep hours and number of sleep opportunities by sleep log, self-reported sleep quality and sleepiness in the intervention group compared to the control group, but no significant differences in mean sleep duration by sleep log and objective sleep parameters from mattress sensors.
Multicomponent Intervention
Scott, 2010 U.S.	Nurses 62 97%	38	1-hr education with continuous institutional changes (4-wk and 12-wk follow-up)	1-hr fatigue countermeasure education together with institutional changes including increasing unit staffing, providing completely relieved breaks and meal periods, and use of strategic naps during breaks with a sleep recliner and 20-min timer	No control	PSQI, ESS, total sleep duration, workday sleep duration, nonwork day sleep duration, night shift sleep duration	Drowsiness and sleep episodes at work, drowsy driving and motor vehicle crashes, errors and near errors,	There were significant increases in total sleep duration, workday sleep duration, nonwork day sleep duration, night shift sleep duration at 4-wk and 12-wk follow-up. There was a significant improvement in PSQI total score at 12-wk follow-up, but no significant changes in ESS score.
Zhang, 2023 China	Frontline nurses during COVID 52 96%	31	4 wks	Holistic sleep improvement strategies including scientific human resource management, comfortable sleep environment establishment, self-relaxation, and self-adjustment training and humanistic care	No control	PSQI-Chinese total score and subscale scores	None	There were significantly improved PSQI total score and subjective sleep quality, sleep efficiency, and sleep disturbance scores compared to the baseline.

Notes. PSQI = Pittsburg Sleep Quality Index, ER = Emergency, ICU = Intensive Care Unit, HRV = Heart Rate Variability, OBI = Occupational Burnout Inventory, KSS = Karolinska Sleepiness Scale, ESS = Epworth Sleepiness Scale, VSH = Verran Snyder Halpern Scale, PVT = Psychomotor Vigilance Task, ISI = Insomnia Severity Index, HADS = Hospital Anxiety and Depression Scale, HADS-A = Hospital Anxiety and Depression Scale-Anxiety, HADS-D = Hospital Anxiety and Depression Scale-Depression, KSQ = Karolinska Sleep Questionnaire, SMBQ = Shirom-Melamed Burn-out Questionnaire, WIPL = Work Interference with Personal Life Index, PSS = Perceived Stress Scale, DBAS = Dysfunctional Beliefs and Attitudes about Sleep, VAS = Visual Analog Scale, CIS = the Checklist Individual Strength questionnaire, RT = response time, PSG = Polysomnography, PDA = Personal Digital Assistant, CES-D = Center for Epidemiologic Studies Depression, TST = Total Sleep Time, SE = Sleep Efficiency, WASO = Wake After Sleep Onset, SSS = Stanford Sleepiness Scale, ATS = Accumulated Time with Sleepiness Scale, DSS = Driver Sleepiness Scale, BT = Bed Time, GUT = Get-up Time, TIB = Time in Bed, TST = Total Sleep Time, SL = Sleep Latency, FI = Fragmentation Index, GSQS = Groningen Sleep Quality Scale, MSBR = Mindfulness-Based Stress Reduction, BP = Blood Pressure; HR = Heart Rate; SSQ = Spiegel Sleep Quality Questionnaire, FIRST = Ford Insomnia Response to Stress Test; CD-RISC = Connor-Davidson Resilience Scale, SPT = sleep period time, DS-CPT = Degraded-Stimulus Continuous Performance Test, POMS = Profile of Mood States, SWD = Shift Work Disorder, SHI = Sleep Hygiene Index, MEQ = Morningness-Eveningness Questionnaire, FOSQ = Functional Outcomes of Sleep Questionnaire, GAD = General Anxiety Disorder, QMWS = Questionnaire on Medical Worker’s Stress, CBT-I = Cognitive Behavioral Therapy for Insomnia, STAI = State Trait Anxiety Inventory, GSDS = General Sleep Disturbance Scale, SSI = Standard Shiftwork Index, SETS-SW = Sleep Enhancement Training System for Shift Workers, SO = Sleep Onset, DBRT = Diaphragmatic Breathing Relaxation Training, SAS = Self-Rating Anxiety Scale, SDS = Self-Rating Depression Scale, SHT = Self-help therapy, PHQ = Patient Health Questionnaire, MBI = Maslach Burnout Inventory, SF = Short Form, LDL = Low-density Lipoprotein, HDL = High-density Lipoprotein, DSST = Digit Symbol Substitution Task, LCT = Letter Cancellation Task, MTCQShift = Munich ChronoType Questionnaire for Shiftwork, CRP = Salivary C-reactive Protein, MQ = Maastricht Questionnaire, REQ = Recovery Experience Questionnaire, KPDS = Kessler Psychological Distress Scale, UWES = Utrecht Work Engagement Scale, wk = week.