Shift work-related problems in 16-h night shift nurses (2): Effects on subjective symptoms, physical activity, heart rate, and sleep

A 90- followed by a 30-min nap reduces fatigue whereas a 30- followed by a 90-min nap maintains cognitive performance in night work: A randomized crossover-pilot study

OBJECTIVE

To investigate the effects of combinations of brief naps (a 90- followed by a 30-min nap vs. a 30- followed by a 90-min nap) on sleep inertia, reducing sleepiness and fatigue, and maintaining performance during night hours.

METHODS

This randomized, comparative, repeated-measure, cross-over study investigated subjective and cognitive performance in 12 healthy females, evaluated in three experimental nap conditions: 1) from 22:30 to 00:00 and 02:30 to 03:00 (Pre90-NAP group), 2) from 23:30 to 00:00 and 02:30 to 04:00 (Pre30-NAP) group, and 3) no naps (NO-NAP group). Participants' body temperature, psychomotor vigilance task (PVT) and Uchida-Kraepelin test (UKT) scores, and subjective feelings of drowsiness and fatigue were evaluated. Sleep state was determined by an actigraphy monitoring device worn by participants.

RESULTS

Regardless of timing, both 90-min naps were associated with sleep inertia, and both 30-min naps with minimal sleep inertia. Reaction times were shorter and fewer errors were committed at 2 h post-nap in the Pre30-NAP and Pre90-NAP groups compared with those at the same time in the NO-NAP group. Adding a 90-min nap to a 30-min nap reduced subjective fatigue and shortened reaction times, and adding a 30-min nap to a 90-min nap was effective in maintaining performance, suggesting a synergistic effect.

CONCLUSIONS

Taking two naps during a night work can mitigate sleepiness and fatigue, and maintain performance. A 90- followed by a 30-min nap reduced fatigue and reaction time, and a 30- followed by a 90-min nap maintained cognitive performance in the early morning.

Comparison of Fatigue Level, Musculoskeletal Disorders and Physical Activity Level in Aircraft Engineers Working in the Morning Shift and Night Shift

Background Shift work is a system in which different groups of workers work at different times of the day and night. It may affect the physiological health of an individual and hence fatigue, musculoskeletal disorder and changes in physical activity may arise.

Objective To compare the fatigue level, musculoskeletal disorders (MSDs) and physical activity level in aircraft engineers working in morning shift and night shift.

Method The study consisted of 100 aircraft engineers working at Indira Gandhi International Airport, Terminal 1. 50 aircraft engineers working in morning shift and 50 aircraft engineers working in night shift participated in the study. Self-administered questionnaire i. e., Chalder Fatigue Scale, Nordic Musculoskeletal Questionnaire and International Physical Activity Questionnaire were used to access the fatigue level, the number of MSDs, and physical activity level, respectively.

Results The results showed significant difference in fatigue level, and the level of physical activity morning shift versus night shift workers (p<0.001). The mean value of fatigue level in morning shift was 4.9 and in night shift was 14.6. The average mean value of physical activity level in morning shift was 1972.61 MET min a week and in night shift was 1277.83 MET min a week. MSDs were more common in night shift workers as compared to morning shift workers.

Conclusion The findings of the study suggested an increased in the level of fatigue and decrease in the physical activity level among aircraft engineers working night shift compared to those working morning shift. There are more MSDs in aircraft engineers working night shift as compared to those working morning shift.

The effect of extended shift work on autonomic function in occupational settings: A systematic review and meta-analysis

OBJECTIVE

To examine the effect of 24-h shift work on autonomic nervous system function via heart rate variability (HRV) methodologies.

METHODS

Electronic databases (indexed in either PubMed, MEDLINE, CINAHL, SPORTDiscus, or OpenDissertations) were searched from January 1964 to March 2023. A modified Downs and Black checklist was used for assessing methodological quality and the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach was used to evaluate the quality of evidence. Study design, study population, study sample, shift work description, and assessment of HRV metrics and methods were extracted from each study.

FINDINGS

A total of 58 478 study articles were identified, of which 12 articles met inclusion criteria. Sample sizes varied from eight to 60 participants, with the ratio of low- to high-frequency HRV (LF/HF) as the most common frequency-domain variable reported. Of the nine included studies that observed LF/HF, three (33.3%) demonstrated a significant increase after 24-h shift work. Moreover, of the five studies that reported HF, two (40%) noted a significant decrease after 24-h shift work. When observing risk of bias, two (16.6%) studies were low quality, five (41.7%) were moderate quality, and five (41.7%) were high quality.

INTERPRETATION

There were inconsistent findings demonstrating an effect of 24-h shift work on autonomic function, with a suggested shift away from parasympathetic dominance. Discrepancies in HRV methodologies, such as the duration of recordings and hardware used for measurement, may have contributed to the disparity in findings. In addition, differences in roles and responsibilities across occupations may explain the incongruence in findings across studies.

What Determines Step-Rate at Work? An Investigation of Factors at the Shift, Worker, Ward, and Nursing Home Levels in Eldercare

Objectives

Current knowledge on the determinants of step-rate at different organizational levels is limited. Thus, our aim was to identify, in eldercare, at what workplace level differences in step-rate occur and to identify determinants of workers’ step-rate at these levels.

Methods

Participants were 420 eldercare workers from 17 nursing homes (126 wards) in Denmark. Accelerometry was used to assess step-rate (steps per hour) of workers over multiple shifts. We assessed various determinants at different levels of the workplace, i.e. at the (i) shift, (ii) worker, (iii) ward, and (iv) nursing home levels. Variance components analysis identified the percentage contribution to total variance in step-rate from each respective level. Multi-level linear regression modelling was used to investigate the association between candidate determinants at each level and step-rate.

Results

Differences in eldercare workers’ step-rate occurred primarily between shifts (within workers; 44.9%) and between workers (within wards; 49.1%). A higher step-rate was associated with: (i) weekend and evening shifts (versus weekday/day); (ii) job as a care helper (versus care aide) and an increased proportion of time spent on direct care tasks; (iii) working in a somatic ward (versus dementia), an increased resident–staff ratio and permission to take unscheduled breaks; and (iv) lack of elevators.

Conclusions

We found that nearly all variability in step-rate in eldercare work occurs between shifts (within workers) and between workers (within wards). The main determinants of step-rate were related to the type of shift, type of work tasks, staffing ratio, break policy, and availability of elevators.

The effects of a 120-minute nap on sleepiness, fatigue, and performance during 16-hour night shifts: A pilot study

Objective

To investigate sleepiness, fatigue, and performance following a 120‐minute nap during simulated 16‐hour night shifts based on subjective and objective assessments.

Methods

Fourteen females participated in this crossover comparative study. Three experimental nap conditions were used: naps from 22:00 to 00:00 (22‐NAP), 00:00 to 02:00 (00‐NAP), and 02:00 to 04:00 (02‐NAP), respectively. Measurement items were sleep parameters, sublingual temperature, a Visual Analog Scale for sleepiness and fatigue, a single‐digit mental arithmetic task (for 10 minutes), and heart rate variability. Participants wore an ActiGraph to estimate their sleep state.

Results

There was no difference in the sleep parameters at the time of naps among the three conditions. Immediately following a 120‐minute nap, sleepiness and fatigue increased, and the number of calculations performed in the single‐digit mental arithmetic task decreased in any of the conditions. In particular, immediately after the 02‐NAP, fatigue and high‐frequency power (HF) were higher than after the 22‐NAP. In the early morning (from 05:00 to 09:00), in the 22‐NAP, sleepiness and fatigue increased, and performance and sublingual temperature decreased more than in the 00‐NAP and 02‐NAP. Furthermore, the ratio of errors was significantly lower in the 00‐NAP than in the 22‐NAP in the early morning.

Conclusions

A 120‐minute nap taken from 22:00 to 02:00 may cause temporary sleepiness after waking, increase fatigue and reduce performance. Greater attention should be given to naps taken at a later time (ie, 02‐NAP). In addition, taking a nap starting at 00:00 might decrease the risks of errors in the morning.

How many calories do nurses burn at work? A real-time study of nurses' energy expenditure

Background

Nurses have high rates of overweight and obesity, and physical inactivity is one key determinant of weight gain.

Aims

The present study aims to quantify nurses' energy expenditure over a standard 12-hour shift to establish whether activity levels at work are too low to maintain a healthy body weight.

Methods

Ward-based nurses (n = 96, 90 female, mean age = 36 years, mean experience = 10 years, mean body mass index = 26.6) wore heart rate and physical activity monitors for the duration of one full working shift. Heart rate and activity data were used in combination with demographic information to estimate each nurse's energy expenditure over 12 hours.

Results

On average, nurses burned 2.12 kcals per minute while at work, equating to 1521 kcals/6364 kJ (SD = 403 kcals/1686 kJ) per 12-hour shift. Energy expenditure over 12 hours varied markedly between nurses (from 812 kcals/3397 kJ to 3005 kcals/12,573 kJ) but was sufficient in 72% of participants (assuming minimal resting levels of energy expenditure for the 12 hours not at work) to burn off a daily calorie intake of 2000 kcals.

Conclusions

Three-quarters of nurses expend more energy on working days than is required to maintain a healthy body weight if dietary intake does not exceed recommended levels.

Association between sleep and fatigue in nurses who are engaged in 16 h night shifts in Japan: Assessment using actigraphy

AIM

To determine the association between sleep and fatigue in nurses who are working in a two-shift system, including 16 h night shifts.

METHODS

Sixty-one nurses were assessed on their sleeping and napping over 9 days, using actigraphy and a sleep diary. Work-related feelings of fatigue were measured by using the "Jikaku-sho shirabe" questionnaire and the Cumulative Fatigue Symptoms Index.

RESULTS

The main night-time sleep started after 00:00 hours in half of the participants and the average start and end times were significantly delayed among the participants in their 20s, compared to those in their 40s . Although ~90% of the participants napped during and/or after a night shift, only 50.8% napped for >2 h during their shift and 32.8% napped in the morning after a night shift. In the high-fatigue group, significantly more nurses went to sleep after 00:25 hours than before 00:26 hours the night after a night shift. Furthermore, those nurses who napped for >2 h during their night shift exhibited a significantly lower rate of some cumulative fatigue symptoms, compared to those who did not. In addition, a combination of napping in the morning after a night shift and beginning the following night-time sleep before 00:26 hours were associated with a significant decrease in fatigue symptoms.

CONCLUSIONS

Naps at an appropriate time and of an appropriate duration, along with the practice of beginning the night-time sleep early after a night shift, might relieve cumulative mental fatigue in nurses who are working 16 h night shifts.

The effects of nighttime napping on sleep, sleep inertia, and performance during simulated 16 h night work: a pilot study

OBJECTIVES

This study aimed to elucidate the effects of two naps taken at night on morning waking state and performance.

METHODS

The participants were 12 women. The experiment was performed in a laboratory over 2 days (16:00-09:00). In this crossover comparative study, three experimental nap conditions were used (naps from 22:30 to 00:00 and from 02:30 to 03:00 (22:30-NAP), 00:30 to 02:00 and 04:30 to 05:00 (00:30-NAP), and no naps (NO-NAP), respectively). Measurement items were a Visual Analog Scale for sleepiness and fatigue, the Psychomotor Vigilance Test (PVT), and single-digit addition calculations (10 min) every hour for 18 h from 16:00 to 09:00, excluding nap times.

RESULTS

Sleep inertia and sleepiness were noted directly after napping. Less sleepiness and fatigue were noted in the nap groups between 06:00 and 09:00 in the morning than in the NO-NAP condition and PVT response times were faster. Since participants in the nap groups were able to conduct more single-digit addition calculations, the performance of these groups appeared to be superior to that of the NO-NAP condition. Furthermore, the performance of calculations was significantly better in the 00:30-NAP than in the 22:30-NAP.

CONCLUSIONS

Taking two naps during a simulated night shift helps improve sleepiness and fatigue and maintain performance. Taking a nap in the early morning appears to be promising for improving the waking state.

Disabling low back pain associated with night shift duration: sleep problems as a potentiator

BACKGROUND

We investigated how night shift duration and sleep problems were jointly associated with disabling low back pain (LBP) among workers in different occupations.

METHODS

An online-survey was conducted regarding work schedules, disabling LBP, sleep problems, and other relevant factors in 5,008 workers who were randomly selected from a market research panel. Multiple logistic regression analyses determined the joint associations of night shift duration (0 [permanent day shift], <8, 8-9.9, 10-15.9, ≥16 hr) and sleep problems (no, yes) with disabling LBP adjusted for potential confounders.

RESULTS

A night shift ≥16 hr was associated with a significant increase in the likelihood of disabling LBP. The magnitude of this association was elevated when participants perceived sleep problems including both sleep duration and quality.

CONCLUSION

Associations between extended night shifts and disabling LBP became stronger in the presence of short or poor quality sleep.

Job demands and resting and napping opportunities for nurses during night shifts: impact on sleepiness and self-evaluated quality of healthcare

The aim of this field study is to describe night shift resting and napping strategies and to examine their beneficial effects on sleepiness and quality of work. The study was carried out with 16 nurses working in an intensive care unit. Data collected during 20 night shifts were related to job demands (systematic observations), to the duration and timing of rests and naps taken by nurses (systematic observations, sleep diaries), to sleepiness (Karolinska Sleepiness Scale), and to quality of work scores (visual analog scale). The results showed that the number of rests and naps depended on the job demands. Resting and napping lowered the levels of sleepiness at the end of the shift. There was no direct relationship between sleepiness and the quality of work score. Discussions about the choice of indicators for the quality of work are necessary. Suggestions for implementing regulations for prescribed napping during night shifts are presented.

[How are leisure activity and shiftwork schedule associated with recovery from fatigue in shiftwork nurses?]

OBJECTIVES

The period of leisure is an appropriate time to recover from work-induced fatigue, though some recovery takes place during rest breaks at work. Recently, much attention has been paid to the critical role of leisure activity in recovery. However, the findings relevant to shiftwork nurses who cannot take a day-off regularly are limited. This study explored how leisure activity during days off and shift work schedule are associated with recovery from fatigue in nurses working rotating shifts.

METHODS

A total of 426 nurses working rotating shifts at a university hospital returned a questionnaire regarding leisure activity and fatigue (response rate: 81.5%). Nurses were eligible for this study if they were female, worked 2 or 3 shifts, and had no missing data. A total of 390 respondents satisfied the inclusion criteria. A factor analysis classified their responses on how to spend an assumed period of two consecutive days off into three activity types: outdoor-, sleep-, and indoor-oriented. Fatigue (recovery from fatigue, accumulated fatigue, burnout), work conditions (working time, overtime, nightshift napping), sleep (sleep duration before day shift or day off, sleepiness) were measured. These data were analyzed using a two-way mixed model analysis of covariance (type [outdoor, sleep, indoor], shift schedule [two or three-shift system]). Covariates included age, length of career, partner, children, and hospital ward. Multiple regression analyses were performed to examine the factors determining the level of fatigue.

RESULTS

Outdoor-oriented nurses showed significantly faster fatigue recovery, lower accumulated fatigue and less burnout symptoms than others, regardless of the shiftwork schedule. In contrast, sleep-oriented nurses showed significantly slower recovery from fatigue. Besides, their level of fatigue deteriorated more when they worked under a 3-shift system (counter-clockwise) compared with under 2-shift system (with mainly 16-hour nightshift). Multiple regression analysis indicated that sleep-oriented type of leisure activity, workload perception of working time, work-induced insomnia and length of nightshift naps were significantly related to fatigue-related outcomes.

CONCLUSIONS

The primary finding of this study suggests that the level of fatigue is associated with the type of leisure activity, especially sleep-oriented activity, during shiftwork nurses' days off. Also, ensuring sufficient nightshift nap time may be one of the most important nightshift-related factors for recovery from fatigue. The present findings may have implications for appropriate activities during days off as factors facilitating recovery from work, though further investigations are needed to examine the causal links.

Physiological and behavioural response patterns at work among hospital nurses

AIM

The aim was to determine whether hospital nurses are experiencing physiological strain at work by examining their physiological and behavioural response patterns over 12-hour shifts.

BACKGROUND

Excessive workload for nurses may lead to poor quality of care and high nursing turnover rates. Energy expenditure (EE), heart rate (HR) and work pace (WP) can be used to examine the physiological impact from the workload.

METHODS

A total of 145 nurses wore monitors for one 12-hour day shift to record HR and WP, which were used to calculate EE. Individual and work-related factors were assessed through questionnaires and work logs.

RESULTS

Energy expenditure accumulated over the 12 hours reached the EE level of 8-hour shifts in which individuals work at a moderate physical intensity level. The HR data indicated a moderate cardiac stress level throughout the shifts, despite which WP decreased after 15.00 hours. Inadequate work break and sleep, family care-giving responsibility and aging may challenge work recovery.

CONCLUSIONS

Nursing workload of 12-hour shifts has a negative physiological impact on hospital nurses.

IMPLICATIONS FOR NURSING MANAGEMENT

Nurse managers need to be aware of the physiological strain experienced by staff nurses, and focus on ensuring sufficient breaks and proper work accommodations for older nurses.

Differences in medical error risk among nurses working two- and three-shift systems at teaching hospitals: a six-month prospective study

Shift work, including night work, has been regarded as a risk factor for medical safety. However, few studies have investigated the difference in medical error risk between two- and three-shift systems. A total of 1,506 registered nurses working shifts at teaching hospitals participated in this study to evaluate the difference in medical error risk between two- and three-shift systems. After adjustment for potential confounding factors using a log Poisson generalized estimating equation model, the results showed significantly higher frequencies of perceived adverse events over 6 months in the three-shift than in the two-shift system, with estimated mean numbers of adverse events of 1.05 and 0.74, respectively. Shorter intervals after night shifts and greater frequency of night shifts in three-shift systems, which reduce the recovery time from night shift work, may be linked to increased medical errors by nurses.

Stress assessment in acute care department nurses by measuring interleukin-8

BACKGROUND

Cytokines, such as interleukin (IL)-8, have been shown to be related to depressive symptoms or inflammatory diseases and may be useful as stress biomarkers.

AIM

This study was to assess whether urinary IL-8 levels were reliable indicators of stress among acute care department (AD) nurses.

METHODS

A total of 118 nurses participated in the study. Urinary IL-8 levels of 49 AD nurses were compared with levels of a control group of 69 chronic care department (CD) nurses.

RESULTS

The urinary IL-8 levels of AD nurses, who reported a higher level of professional stress, were higher than the levels of CD nurses (P < 0.01).

CONCLUSION

Measurement of urinary IL-8 may be an appropriate biomarker for stress assessment in nurses.

Assessment of salivary human herpesvirus-6 and immunoglobulin a levels in nurses working shifts

PURPOSE

The purpose of the present study was to assess whether salivary human herpesvirus (HHV)-6 acted as a new sensitive stress marker, providing a reliable indicator of stress among shift work nurses. Salivary HHV-6, immunoglobulin (Ig) A and mood states were compared among nurses who worked day shifts only and nurses who worked different numbers of night shifts.

METHODS

Participants included 56 female nurses working in Japanese general hospitals. The 56 subjects were categorized into three groups: Group A (n = 7), which consisted of nurses who only worked day shifts; group B (n = 29), which consisted of nurses working shifts with £8 night shifts per month; and group C (n = 20), which consisted of nurses working shifts with (3) 9 night shifts per month. Mood was assessed using the Profile of Mood States Short Form Japanese version (POMS-SFJ). Salivary biomarker levels and mood were compared among the three groups.

RESULTS

Although the salivary HHV-6 level was significantly higher in group C than in group A (p < .05), salivary IgA and mood levels were not significantly different among the three groups.

CONCLUSION

Salivary HHV-6 level may be a more sensitive stress marker than salivary IgA or mood for assessing chronic fatigue in nurses working shifts. Improvement to shift assignments using assessment by salivary HHV-6 is required.

Cardiac autonomic imbalance in female nurses with shift work

The pathophysiology underlying the shift work-related cardiovascular disease is still poorly understood. The chronic effects of shift work on cardiac autonomic functions were assessed in 47 hospital nurses working under a rotating three-shift system (shift nurses) and 36 public health nurses without shift work (non-shift nurses). The heart rate variability, %LF and %HF (i.e., proportions of sympathetic and vagal activities, respectively), and LF/HF ratio were calculated from the electrocardiographic RR intervals by using autoregressive spectral analysis, and heart rate-corrected QT interval (QTc and QT index) was also measured. The LF/HF ratio, %LF, and QT index were significantly larger in the shift nurses than in the non-shift nurses; also, the power spectral density of HF (PSD(HF)) was significantly decreased in the shift nurses. There was a significant, inverse correlation between the corrected QT interval and PSD(HF) in the non-shift nurses, but not in the shift nurses. It is suggested that shift work in female nurses may cause a sympathodominant state due to depressed vagal tones. Also, a pathophysiology of shift work-related cardiovascular disease, derived from the present and previous findings, may be characterized by the attenuation of the inverse association between the corrected QT interval and vagal activity observed in non-shift workers.

Effects of shift work on autonomic and neuromotor functions in female nurses

Thirty-seven nurses with shift work, working under a rotating three-shift system, and 37 nurses without shift work, having worked during the daytime for one or more years prior to this study, were examined to assess the effects of shift work on cardiac autonomic and neuromotor functions. Their ages ranged from 25 to 58 yr. The electrocardiographic (ECG) R-R interval variability, %LF and %HF (i.e., proportions of sympathetic and parasympathetic activities, respectively), and LF/HF ratio were computed by means of autoregressive spectral and component analyses. The %LF and LF/HF ratio were significantly larger in the nurses with shift work than in those without shift work, although there was no significant difference in the heart rate-corrected QT interval on ECG between them. And, hand-ear coordination differed significantly between the nurses with shift work and those without. Despite the presence of potential selection bias, it is suggested that shift work in nurses may cause not only a long-term sympathodominant state but also some neuromotor impairment.

An occupational health physician's report on the improvement in the sleeping conditions of night shift workers

This paper reviews briefly our research findings on sleep and health for shift workers at a bakery and a dish factory and aims to give some information on health protection with improved sleep. Our medical examinations revealed that rises in blood pressure (BP) were frequently observed in male bakery workers on the fixed night shift. They took a two-hour nap from 1:00 to 3:00 during the night shifts according to our advice. As a result, their diastolic BP significantly decreased in subsequent years. Women working shifts before 3:00 at a dish factory seemed to show more sleep disturbance, higher daytime sleepiness, and more fatigue than those working shits from 3:00. Total sleep hours taken during the daytime was similar between two groups. Among the dish, factory workers who switched to midnight or night shifts, 70% reported slow recovery from fatigue and 30% felt deteriorated health. These women also reported increased efforts to obtain a deep sleep, probably making up for shortened sleep. Occupational physicians can act to improve shift work conditions through monitoring the health of workers, applying naps, and designing possible schedules to secure deep, sufficient sleep.

Modifying effects of perceived adaptation to shift work on health, wellbeing, and alertness on the job among nuclear power plant operators

This study examined the relationship between perceived adaptation to shift work and shift-related problems. A total of 608 male operators at nuclear power plants completed a set of validated questionnaires including a modified version of the Standard Shiftwork Index, which covered adaptation to shift work, fit to job content, chronotypes, chronic fatigue, sleep, naps, shift work locus of control (SHLOC), psychological health, social/family life, daytime sleepiness, workload, alertness on the job, and lifestyle factors. Participants were divided into two groups according to their perceived level of adaptation to shift work. The good adaptation group showed better outcomes than the poor adaptation group in terms of fit to job content, chronic fatigue, daytime sleep before night shifts, social and family disruption, SHLOC, psychological health, and alertness during night shifts (ps<0.001). Operators who reported good adaptation also took a more frequent, longer nap and more cigarettes during night shifts (ps<0.05). The cross-sectional study design cannot determine a causal relationship between perceived adaptation and shift work problems, yet the present results suggest that the effects of working shifts may be modified by perceptions of shift work adaptation.

Mental Health Status, Shift Work, and Occupational Accidents among Hospital Nurses in Japan

A questionnaire survey was conducted with questions from the 12-item General Health Questionnaire, among others, targeting 4,407 nurses in 8 general hospitals in Japan, in the hope of improving the work environment of nurses and to provide data that will allow a discussion of the measures necessary for preventing medical errors, thus improving occupational health. For each type of accident, the percentage of those who had made medical errors was significantly higher for the "mentally in poor health" group than for the "mentally in good health" group (p<0.0001). The percentage of nurses in the "mentally in good health" and "mentally in poor health" groups who had experienced occupational accidents over the past 12 months (i.e., whether they were "with errors" or "without errors") was calculated for each of the following four types of medical accident: (1) drug-administration errors, (2) incorrect operation of medical equipment, (3) errors in patient identification, and (4) needlestick injuries. For each type of accident, the percentage of those who had made medical errors was significantly higher for the "mentally in poor health" group than for the "mentally in good health" group (p<0.0001). Multiple logistic regression analyses revealed significant associations between experience of medical errors in the past 12 months and being mentally in poor health, with night or irregular shift work, and age.

The role of prescribed napping in sleep medicine

Napping, when its timing and duration are designed properly, has the potential to improve our daily lives. Laboratory findings indicate that scheduled napping promotes waking function after normal sleep at night, and also counteracts decreased alertness and performance under conditions of sleep deprivation. Since these effects are evident even with naps shorter than 30 min, shiftwork problems may be alleviated by the short nap at the workplace. Multiple short naps are effective in managing excessive daytime sleepiness in narcoleptic patients under medication. The therapeutic usefulness of napping in other sleep disorders, however, remains to be established. Epidemiological studies suggest a decrease in the risk of cardiovascular and cognitive dysfunction by the practice of taking short naps several times a week. Sleep inertia occurs immediately after napping, but its severity can be minimized by avoiding long naps that may result in awakening from deep non-rapid eye movement sleep. Activities during the post-nap period should also be undertaken carefully. To allow the maximum advantage to be gained from napping, more efforts are needed to identify the strategies of napping that are compatible with individual cases including aging, work schedules, and sleep disorders, and to examine their efficacy in real-life settings.