Background:Mindfulness interventions are considered an effective strategy for preventing mental health problems among health care workers (HCWs). While prior reviews have often included facilitator-guided or multicomponent interventions, it is unclear whether self-guided digital mindfulness interventions can also be effective without professional or in-person support. Objective:This systematic review aimed to investigate the effects of self-guided digital mindfulness interventions on the mental health and well-being of HCWs. Methods:This work was conducted as part of the DeLiGHT project. We searched electronic databases, including PubMed (MEDLINE), Embase, Cochrane CENTRAL, PsycINFO, PsycARTICLES, and the Japan Medical Abstract Society database, from inception in 2010 to July 25, 2023. To ensure timeliness, we performed an updated search on December 27, 2025. Database searching yielded 37,851 abstracts and 145 studies that examined the effectiveness of digital health interventions for workers in the initial 2023 screen. In the present study, we limited the included studies to those that met the following criteria: randomized controlled trials (RCTs) using self-guided digital mindfulness interventions (eg, smartphone apps or web-based programs) delivered without face-to-face or professional support compared to waiting list controls or usual care among HCWs. The updated search in 2025 yielded 6328 additional records, of which 11 studies were examined. Study quality was assessed using the Cochrane Risk of Bias tool, with meta-analyses conducted using a random-effects model. Results:A total of 9 RCTs with 3088 participants were included in the final analysis. The study populations were diverse, covering North America, Europe, Oceania, and Asia. Interventions were delivered via various digital platforms, including commercial mindfulness apps (n=3), social networking service tools (n=3), and web-based programs (n=3), with an average duration of 6.17 weeks (range: 1.5-18 wk). Five studies assessed outcomes only postintervention, and 4 included short-term follow-up (4-12 wk); no long-term effects were evaluated. The meta-analysis showed a significant beneficial effect on depression (standardized mean difference [SMD]=-0.44, 95% CI -0.88 to -0.00; P=.049), anxiety (SMD=-0.29, 95% CI -0.51 to -0.06; P=.011), perceived stress (SMD=-0.42, 95% CI -0.77 to -0.06; P=.02), and well-being (SMD=0.20, 95% CI 0.09 to 0.30; P<.001) immediately postintervention. The adherence rates reported across studies were highly variable, ranging from 19% to 56%. According to the Cochrane Risk of Bias tool, most studies were rated as having some concerns or a high risk of bias. The certainty of evidence included in the analysis ranged from "Low" to "Very Low." Conclusions:Overall, low to very low certainty evidence suggests that self-guided digital mindfulness interventions may have short-term beneficial effects on depression, anxiety, perceived stress, and well-being among HCWs. Future high-quality studies are needed to examine the long-term effects and cross-cultural generalizability of these interventions.

Traditional paper-and-pencil methods have limitations for data collection in occupational health research. Here, we introduce a new web-based version (Fatigue checker web-ver.) of an application designed to better facilitate survey management and communication with participants. The application operates on mobile web browsers and integrates with LINE, Japan’s most popular messaging app, and contains customizable forms, psychological tasks such as the Psychomotor Vigilance Task (PVT), Flanker Task, and n-back Task. Daily schedule acquisition is achieved via a dedicated user interface. Cross-correlation analysis showed fair synchronization between the app and gold-standard PVT equipment, indicating the app’s reliability in measuring reaction times. Specifically, the analysis revealed significant cross-correlation for mean reaction time, median reaction time, mean reciprocal reaction time, and number of lapses, which indicates that the app can reliably measure fatigue and alertness levels. Since its release, the app has been successfully employed collecting high-quality data in six projects involving 571 participants. Despite minor issues, the app significantly improves the efficiency and accuracy of remote surveys, offering valuable insights into workers’ health and safety. It also enables occupational health and safety specialists to monitor workers and workplaces from a broader perspective than traditional methods. The public version of the app also enables every worker to monitor their own occupational health and safety status. Insights from repeated self-checking of fatigue will promote better working conditions and environments.

Here, we examine the effectiveness of a participatory artificial intelligence (AI)-driven shift-scheduling mobile application (which reflects the local improvement needs in shift scheduling) in improving the sleep quality of shift-working geriatric caregivers. Thirty-five shift-working geriatric caregivers participated in this 4-month cross-over interventional study. Half of the participants in the first 2 months followed the intervention schedule created by the AI-driven shift-scheduling mobile application, while the remaining participants followed the manually created control schedule. The improvement needs in shift scheduling, derived from occupational-fatigue counselling, were as follows: avoiding backward rotating shifts, reducing consecutive shifts, extending shift intervals and ensuring a day-off after a night shift. Sleep phases were evaluated using a ring-type sleep tracker. The effectiveness of the intervention was examined using three-way multilevel analyses (condition × shift × time). Deep sleep (N3) and rapid eye movement sleep were significantly more pronounced in the intervention condition compared with the control condition (p = 0.016, p = 0.046, respectively). However, no significant differences were detected for other outcomes. Moreover, we examined how shift combinations affected sleep outcomes. As a result, two consecutive late shifts and backward rotating shifts significantly deteriorated sleep quality and length (all p < 0.05). Our findings suggest that the shift-scheduling app reduced the backward shift rotations, resulting in significantly better sleep outcomes than from manual schedule creation. However, the magnitude of reduction in backward rotating shifts was not so remarkable. Therefore, the positive outcomes can also be attributed to enhanced employees' working time control by reflecting the local improvement needs. Trial Registration: UMIN Clinical Trials Registry: UMIN000048495.

Background: Maintaining exercise behavior is important for health. Although exercising with others may be an effective strategy for maintaining this, the association between exercising with others and the maintenance of it as well as the mediators of this association remain unconfirmed. The present study examined whether exercising with others was longitudinally and positively associated with 1-year maintenance of exercise behavior, and this association was mediated by exercise motivation among workers. Methods: This study used data of an online survey-based longitudinal cohort study on 2819 Japanese workers who performed exercise at baseline and responded to a 1-year follow-up survey. This study analyzed 1-year follow-up data of participation in exercise; baseline and 1-year follow-up data of weekly exercise time; and baseline data of exercising with others, exercise motivation, and demographic factors. Participation in exercise (model 1) and weekly exercise time (model 2) after 1 year were indices of 1-year maintenance of exercise behavior. Results: Adjusting for demographic factors, path analyses showed that exercising with others at baseline indirectly and significantly predicted 1-year maintenance of exercise behavior, mediated by exercise motivation and weekly exercise time at baseline (standardized total associations, 0.07 in model 1 and 0.18 in model 2; standardized indirect associations, 0.06 in model 1 and 0.18 in model 2). Conclusions: This study found that exercising with others was indirectly and positively associated with 1-year maintenance of exercise behavior, mediated by exercise motivation. Encouraging participation with others may be effective in supporting motivation and maintaining exercise behavior.

The Reduced Morningness-Eveningness Questionnaire (rMEQ), a five-item version of the 19-item MEQ, is a practical tool for assessing circadian typology or "morningness" and "eveningness" preference. Although we previously validated the Japanese version of rMEQ with MEQ, external validation against an established standard was lacking. This study aimed to additionally validate the Japanese rMEQ in young adults by assessing the dim light melatonin onset (DLMO), a marker of circadian phase, and subjective/objective sleep-wake habits. Twenty healthy young adults (mean age: 23.0 ± 1.9 years) participated in this study and were assessed the circadian typology by rMEQ and MEQ. The sleep-wake habits were measured by sleep diary, actigraphy and the Pittsburgh Sleep Quality Index (PSQI). Salivary melatonin samples were collected to determine DLMO. Results showed significant correlations between rMEQ scores and DLMO, as well as sleep variables based on sleep diary, actigraphy and PSQI. Correlations between rMEQ scores and these variables were consistently stronger than those for MEQ. These findings highlight the validity of the Japanese rMEQ and that the rMEQ more accurately reflects circadian typology and internal circadian phases compared to MEQ, at least in Japanese young adults. The Japanese rMEQ could be a valuable tool for efficiently assessing circadian typologies in Japanese young adults.

We examined cardiovascular responses during driving and investigated the effects of different break patterns on these responses. Forty-seven males in their 40s and 50s participated, and the protocol included three driving sets with four break patterns. One driving set consisted of1 h of city driving and 1 h of highway driving. The four break patterns were a 30-min lunch break (short/ one: SO, n=12), a 60-min lunch break (long/one: LO, n=12), a 10-min break and a 50-min lunch break (long/two: LT, n=12), and a 10-min break and a 20-min lunch break (short/two: ST, n=11). The results showed that the lunch break was significantly effective in moderating diastolic blood pressure, mean arterial pressure and heart rate for all conditions, but the long-break conditions (LO and LT) were also effective in moderating cardiac output and stroke volume. Additionally, for the same total break length, one longer break was more effective in moderating cardiovascular and subjective burden than two shorter breaks. The results of this study suggest that it is important for drivers to take a lunch break, especially a long break around an hour, to reduce cardiovascular and subjective burden during their shift.

Daily rest period (DRP) refers to the interval between the end of one workday and the start of the next. This study examined the joint association of DRP and sleep duration with subsequent sick leave among Japanese daytime employees. A total of 5,593 participants were assessed for DRP and sleep duration at baseline and for sick leave at a one-year follow-up. They were categorized into ten groups based on their DRP and daily sleep duration. Logistic regression analyses for individuals experiencing sick leave for longer than a month showed that the combination of short DRP (<11 h) and sleep duration (<6 h) had a higher odds ratio (4.981, 95% confidence interval [CI]=1.126-22.046) than the reference group. Furthermore, the combination of short DRP and normal sleep duration had a higher odds ratio (8.152, 95% CI=1.801-36.902) than the reference group. Short DRP was associated with subsequent long sick leave.

OBJECTIVES:This study examined the association between daily long working hours (LWHs) and diverse health-related outcomes, using objective and subjective measures. It further evaluated the specific durations of daily LWHs that may be considered inappropriate in cases with adverse health effects. METHODS:98 employees participated in a 10-day observational study. Participants self-reported their daily working hours, subjective states and performed the measurement of blood pressure (BP) and psychomotor vigilance test (PVT) immediately on waking and before bedtime. Objective sleep was recorded nightly using actigraphy. Linear mixed model (LMM) analysis was performed. RESULTS:LWHs were significantly associated with higher systolic BP (β=0.65), greater fatigue (β=1.79) before bedtime, shorter total sleep time (TST; β=-0.09) and higher systolic BP (β=0.76) on waking (all p<0.05). Reduced TST was significantly linked to slower PVT reciprocal response time (β=0.03), higher lapse (β=-1.10) and greater sleepiness (β=-0.20) after waking (all p<0.05). Categorical LMM analysis revealed that working >12 hours was significantly associated with increased fatigue before bedtime, whereas working >13 hours significantly reduced TST compared to working ≤9 hours. Sleeping <6 hours caused significantly poorer PVT outcomes, and sleeping <5 hours caused significantly stronger sleepiness after waking than sleeping ≥7 hours. CONCLUSIONS:Daily LWHs and consequent reductions in sleep duration were associated with adverse outcomes. These findings underscore the importance of daily management of work hours and adequate sleep duration to prevent excessive workload and promote recovery from occupational demands.

OBJECTIVES:This study aimed to clarify the primary preventive effects of physical activity interventions delivered through digital health technology (DHT) on workers' mental health symptoms, and to examine the conditions of attrition and adherence in these interventions. METHODS:We examined randomized controlled trials (RCTs) that analyzed the effects of physical activity interventions delivered through DHT on workers' health outcomes. We included RCTs published in English or Japanese since 2010 and excluded studies that targeted specific diseases or secondary and tertiary prevention. We conducted the search on July 25, 2023, using Cochrane CENTRAL, Embase, PsycINFO, PubMed, and Ichushi-Web, and citation searches. We assessed risk of bias using the Cochrane Risk of Bias Tool version 2, and data were integrated using a random-effects model. Attrition rates were averaged, and adherence was qualitatively reviewed. RESULTS:Eight studies were included in the systematic review, and 5 in the meta-analysis. Pooled effect sizes immediately after intervention were as follows: Cohen d = -0.51 (95% CI, -0.75 to -0.27) for depression and negative affect, and -0.36 (95% CI, -0.60 to -0.05) for perceived stress. The attrition rate was 16.8% and 12.4% for the control and intervention groups, with only 2 studies providing details on adherence. CONCLUSIONS:Physical activity interventions delivered through DHT may moderately improve depression and negative affect, and slightly reduce perceived stress among workers. However, these findings should be interpreted with caution due to the limited number of studies and low evidence certainty. Future studies should explore long-term effects, additional mental health outcomes, and factors affecting adherence.

Circadian typology, or "morningness" and "eveningness," is generally assessed using the Morningness-Eveningness Questionnaire (MEQ), a 19-item scale that could be burdensome in large-scale surveys. To overcome this, a 5-item version known as the reduced morningness-eveningness questionnaire (rMEQ), which is sensitive to the assessment of circadian typology, was developed; however, a validated Japanese version of the rMEQ is yet to be established. This study aimed to develop and validate the Japanese version of the rMEQ. Five essential items for the rMEQ were selected from existing Japanese MEQ data (N = 2,213), and the rMEQ was compiled. We conducted a confirmatory factor analysis for the psychometric properties of the rMEQ and confirmed its robust one-factor structure for evaluating morningness-eveningness (GFI = 0.984, AGFI = 0.951, CFI = 0.935, and RMSEA = 0.091). Reliability was evaluated via internal consistency of rMEQ items using Cronbach's α and McDonald's ω, and the values were 0.618 and 0.654, respectively. The rMEQ scores strongly correlated with MEQ (ρ = 0.883, p < 0.001), and classification agreement (Morning, Neither, and Evening types) between rMEQ and MEQ was 77.6% (Cramer's V = 0.643, Weighted Cohen's κ = 0.72), confirming the validity. The Japanese rMEQ may be a valuable tool for the efficient assessment of circadian typologies.

Objectives: This study aimed to prospectively investigate the association between work environment improvements and multiple mental health outcomes in a large sample of Japanese employees. Methods: A web-based longitudinal study surveyed 20 000 Japanese employees, 7970 of whom completed a follow-up after 1 year. Various types of work environment improvements experienced by workers were assessed using a 24-item checklist. Three mental health outcomes (poor mental health, presenteeism, and high psychosocial stress) were assessed and defined using standardized questionnaires. Results: Overall, as the total number of work environment improvements increased, the odds ratio for mental health outcomes in the follow-up survey decreased by several percentage points, even after adjusting for demographic and occupational factors. Analysis of the types of work environment improvements showed that mutual support improvements were particularly effective in reducing mental health issues. The subgroup analyses also showed that the effectiveness of workplace environment improvements might vary between secondary and tertiary industry workers depending on the types of improvements and mental health outcomes. Conclusions: The study suggests that workplace improvements can significantly affect mental health. The effectiveness of these improvements may vary according to the type of intervention, industry of the targeted workers, and mental health outcomes. This study provides basic data on the effectiveness of workplace environment improvements that can be used for future intervention trials.

OBJECTIVES:Several health issues are associated with irregular sleep patterns. However, it is unclear what causes workers to sleep irregularly. The work interval (WI) between the end of one day's working hours and the start of the next day's working hours contains sleep opportunities, and an irregular WI may result in irregular sleep. This study investigated this association among Japanese daytime workers. METHODS:This study recruited 141 daytime workers without shiftwork for a 14-day observational study. Participants reported the WI duration, WI timing, time in bed (TIB: difference between bedtime and wake-up time), and bedtime timing every day before bedtime. The SD over 14 days was used to calculate the regularity scores. Logistic regression analysis was performed. The dependent variables were ≥60 minutes of TIB SD and bedtime timing SD, whereas the independent variables were WI duration and timing SD. RESULTS:The odds ratios (ORs) (95% CIs) for ≥60 minutes of TIB SD across categories of WI duration SD were 1.000 (reference) for <30 minutes, 1.344 (0.337-5.360) for 30-60 minutes, and 4.743 (1.441-15.607) for ≥60 minutes. The ORs (95% CIs) for ≥60 min of bedtime timing SD across categories of WI timing SD were 1.000 for <30 minutes, 4.154 (1.574-10.965) for 30-60 minutes, and 7.714 (2.124-28.015) for ≥60 minutes. CONCLUSIONS:Regularity of WI was associated with regularity of sleep. To ensure worker health, workers should have regular WI, and if they are exposed to irregular WI, they should make every effort to maintain regular sleep.

BackgroundGiven that nighttime sleep has more recuperative power than daytime sleep, ensuring the former is important to recovery from work, especially for shift-working nurses. In this 1-month sleep log study, we preliminarily examined how the number of monthly nighttime-sleep opportunities relates to fatigue-related outcomes among shift-working nurses.Methods526 nurses were required to record their daily sleep duration immediately after waking from sleep for 1 month. We analysed the associations among the four sleep groups (ie, ≤ 12, 13–19, 20–24 and≥24 nighttime-sleep opportunities per month) and fatigue-related outcomes. A one-way analysis of covariance or generalised linear mixed model (factor: sleep group) was conducted using R (version 4.2.2.) to test the association.ResultsSignificant differences among the four sleep groups were obtained using the excessive fatigue symptom inventory (EFSI), Pittsburgh sleep quality index (PSQI) and the numbers of near-miss incidents. Moreover, significant linear trends were observed in the EFSI and PSQI scores.ConclusionsShift-working nurses who experienced 12 or fewer monthly nighttime-sleep opportunities showed worse fatigue-related outcomes than those who had sufficient monthly nighttime-sleep opportunities. Therefore, more attention should be paid to ensuring monthly nighttime-sleep opportunities when creating a shift schedule.

Mental health problems are prevalent among the working population and must be resolved. We conducted a web-based large-scale study of workers, including a baseline survey and two follow-up surveys, to investigate the associations between self-care behaviors in daily life (e.g., stress coping, sleep, diet, and exercise), work environment improvements, and mental health among Japanese employees from various industries. In this protocol, we demonstrate the study design and demographic data of the participants in the baseline survey. Invitations to participate in this study were sent to 421,825 internet monitor registrants in February 2022. Overall, 20,000 registrants who met the inclusion criteria participated in the survey. There were large variations in occupations and working styles (e.g., physical work, night work, and teleworking) among the participants, and we also found significant differences between male and female participants in the demographic data. An overview of the survey data suggests that the demographic characteristics of the participants in this study are comparable to those reported in previous studies on Japanese employees. We plan to use these survey data in the future to examine the associations of daily lifestyles and work environments with the mental health of Japanese employees.

長時間労働は様々な健康リスクを高め，過労死認定要因のひとつとなっている．近年，高年齢労働者は増加しており，過労死の請求件数も増加傾向である．我々の先行研究では，長時間労働により心血管系の負担が増大するが，特に50代以上の高年齢労働者はその負担増加が大きいことを報告した．しかし，長時間労働時の主観的負担と作業パフォーマンスの変化は不明であったため，本稿ではその解析結果を報告する．30代から60代（65歳未満）の参加者は実験に参加し，9時から22時までの間，3種類の認知課題をそれぞれ45分間行う作業セッションを4回実施した．課題パフォーマンスの指標として各課題の試行数，正解率と反応時間を記録し，主観的負担の指標として疲労，ストレスと眠気を測定した．各指標に対して繰り返しのある二元配置分散分析を行った．結果として，作業者の主観的ストレスと疲労は課題中に上昇したが，年代間の差は認められなかった．課題パフォーマンスは午後の後半（セッション3）と夜（セッション4）で上昇したが，年代間の差は認められなかった．結論として，長時間労働により作業者の主観的疲労とストレスは著しく増大したが，課題パフォーマンスの低下は見られなかった．労働者の健康維持の観点からパフォーマンスが低下しなくても長時間労働が避けられない場合，心身の疲労を蓄積しないよう十分な配慮が必要と考えられる．

勤務間インターバルとは，勤務終了後から翌始業までの休息時間のことを言う．本研究は，勤務間インターバルと睡眠時間の組み合わせと職業性ストレスおよび病気欠勤の関連を検討した．本横断調査は，WEB形式で2022年2月に実施した．日勤労働者13,306名に対して勤務間インターバル，睡眠時間，職業性の高ストレス（職業性ストレス簡易調査票），病気欠勤について尋ねた．参加者を勤務間インターバルと睡眠時間に基づき14群に分類し，これを独立変数，高ストレス判定と病気欠勤を従属変数としたロジスティック回帰分析を実施した．その結果，短いインターバル（<11時間）と通常睡眠（≥6時間）や十分なインターバル（15時間）と短時間睡眠（<6時間）の組み合わせで，基準（十分なインターバルと通常睡眠）と比べてオッズ比が有意に高かった．これは，勤務間インターバルと睡眠時間を十分に確保することが職業性ストレスの低減に重要であり，勤務間インターバル制度によりインターバルが十分に確保されても，睡眠時間が短いと健康リスクが生じる可能性を示している．病気欠勤について，短いインターバルと短時間睡眠の組み合わせでオッズ比が有意に低かった．この原因として，勤務間インターバルが短い（長時間働かなければならない）人々は，忙しいために病気欠勤が必要な状況になっても休みを取れずあるいは取らず，結果的にオッズ比が低くなった可能性が考えられる．

ABSTRACT The cognitive ability to self-monitor one’s current performance is important for hospital nurses to maintain safety and health. However, studies on the effects of rotating shift work on self-monitoring ability are insufficient. We examined the differences in self-monitoring accuracy across shifts in a rotating three-shift system among 30 female ward nurses (mean age 28.2 years). Their self-monitoring ability was calculated by subtracting the predicted reaction times of the psychomotor vigilance task performed just before exiting the workplace from the actual reaction times. A mixed-effect model was employed to assess the effects of shift, awake hours, and prior sleep duration on self-monitoring ability. We observed impaired self-monitoring ability in nurses, particularly after the night shift. Although actual performance remained high across all shifts, their self-predictions on reaction times became pessimistic in the night shift, resulting in a difference of approximately−100 msec. The effect of the shift on self-monitoring was obvious even after adjusting for sleep duration and hours awake. Our findings indicate that the misalignment between their working hours and circadian rhythms may affect even professional nurses. Occupational management that emphasizes maintaining circadian rhythms will improve the safety and health of nurses.