Limited evidence supports melatonin’s efficacy in improving sleep duration after a night shift, with no impact on other sleep quality parameters [2]. Modafinil and armodafinil enhance alertness and reduce sleepiness in individuals with SWD; however, they are associated with adverse events. The combination of caffeine and naps decreases sleepiness during night shifts, though evidence quality is deemed low. Conversely, sedative-hypnotics show no improvements in sleep duration or quality after a night shift. The variability in shift schedules, melatonin dosage, and timing makes it challenging to draw definitive conclusions.

So far, there is no satisfying pharmacological intervention for SWD, emphasizing the need for more advanced experimental designs considering the environmental factors of shift workers.

Simulation studies and a few field studies suggest that daylight or bright light exposure in the early morning can inhibit adaptative circadian phase resetting. In addition, the use of dark goggles was also shown to successfully inhibit phase resetting [3].

However, relying solely on bright light therapy to normalize circadian rhythms disruption resulting from changing shift work is ineffective. Coordinating light therapy and melatonin with the shift work cycle is essential. Recommendations include adjusting shift work cycles, providing 4–5 days off between day and night shifts, incorporating light therapy, light restriction, and sleep timing adjustments to gradually shift the sleep phase. This complex approach, combining bright light therapy and chronotherapy, appears more effective. However, implementing such schedules requires more holidays, and increasing workforce, which could be challenging without organizational support [4].

Recently, one meta-analysis of five studies indicated that exposure to light can decrease sleepiness levels, shift-work-related complaints, and insomnia while increasing psychomotor error, alertness, and daytime sleep duration following night shifts. However, statistical significance was lacking, possibly due to heterogeneity or an insufficient number of studies, emphasizing the need for larger, well-designed randomized control trials [5].

Tailored sleep hygiene guidelines for shift workers were recently developed, involving a collaborative effort by experts in sleep, shift work, and occupational health [6]. The draft guidelines went through three rounds of review, achieving consensus on all recommendations. The final set comprises 18 individual guidelines, referred to as “healthy sleep practices for shift workers” (Table 1). Future research is required to assess the acceptability and effectiveness of these guidelines among shift workers.

Forward and faster rotation may reduce sleepiness during shifts, but its impact on sleep quality is uncertain. Limited evidence suggests that faster rotation decreases off-shift sleep duration, while shorter shift durations (16 hours) increase sleep duration and there is moderate evidence for reducing sleepiness [7]. Changes in shift duration and workweek compression show no clear effect on sleep or sleepiness, but the evidence is uncertain. No evidence is available for other shift schedule changes. More highquality studies, preferably randomized controlled trials, are needed to conclusively determine the effects of shift schedule adaptations on sleep and sleepiness in shift workers.

On-the-job sleepiness and associated safety incidents pose significant challenges for shift workers. However, there has been a lack of attention on the appropriate sleep duration to minimize on-the-job sleepiness among shift workers.

Our recent study focused on nurses in rotational 3-shift work. In a 2-week study using actigraphy and the Epworth Sleepiness Scale, no significant correlation was found between average sleep duration and sleepiness levels. Analyzing shift workers’ irregular sleep-wake patterns revealed varying sleep duration needs for day, afternoon, and night shifts, named the “circadian sleep sufficiency model.” Shorter sleep durations were indicated after night shifts, while longer durations were needed after day or afternoon shifts when sleeping at night. These findings confirm that increasing sleep sufficiency reduces reported sleepiness among shift workers [8].

Based on these findings, we have created a personalized sleep algorithm for shift workers. This framework analyzes real-world sleep data from wearables, utilizing a mathematical model to predict alertness. We identified a novel sleep-wake pattern called adaptive circadian split sleep, optimizing alertness during work and nonwork periods. Our mobile app integrates this framework, suggesting personalized sleep schedules to maximize alertness during specific activities. This approach aims to improve the health and quality of life for shift workers. The algorithm is set to validate a larger group and to confirm its effectiveness in enhancing sleep quality and on-the-job alertness [9].

SWD among shift workers transcends individual concerns, manifesting as a profound societal issue. SWD not only encompasses the issue of insufficient sleep but also influences perceptions of health, emotional well-being, and stress coping mechanisms. Since SWD is a health concern demanding intervention, various studies have historically proposed single or multimodal strategies, yet a consistently effective approach is yet to be confirmed.

We are transitioning into an era of personalized medicine that aligns individual sleep habits and environmental factors with optimal sleep durations and timings tailored to the rapidly evolving landscape of shift work. This paradigm shift is reinforced by cutting-edge digital health devices. Therefore, the imminent availability of strategies attuned to minimizing SWD is now on the horizon.