Shift Work, Fatigue and Workplace Safety: A Psychological Perspective for Factories

How does shift work affect fatigue and accident risk? This guide covers night shifts, sleep, legislation and concrete safety measures for factories.

At three in the morning, the operator at the press line has burning eyes; there are four hours left until the end of the shift. During the day he could hardly sleep at all, because of the children's voices at home, the noise from the street and the endless chores. A small lapse in attention at that moment can turn into a serious workplace accident within seconds. Shift work is indispensable in many factories if production is to run without interruption, but the human body and mind were not designed for night work. In this article we look, from a psychological perspective, at the effects of shift patterns on fatigue, sleep and workplace safety, at the responsibilities the legislation places on employers, and at concrete measures that can be applied in factories.

Why Does Shift Work Cause Fatigue?

The human body runs on a daily internal clock called the circadian rhythm. Sleep, wakefulness, body temperature and attention levels follow a particular rhythm through the day. A night shift demands full attention at the very hours when this rhythm says "sleep"; during the day, in turn, light and noise reduce both the length and the quality of sleep.

This produces fatigue at several levels:

• Sleep debt: Daytime sleep is usually shorter and broken up. Sleep lost across consecutive nights accumulates.
• Reduced attention and reaction time: A sleep-deprived mind notices warnings later, has trouble making decisions and switches to "autopilot" on routine tasks.
• Emotional load: Fatigue increases impatience, anger and anxiety; tensions within the team can grow.
• Social and family disconnection: The lives of family, children and friends are organised around the daytime. A shift worker may be unable to be present at religious holidays, weddings or a child's school events. In Turkey, where extended family relationships matter a great deal, this disconnection is a source of stress in its own right.

Long working hours add to this burden. According to the ILO's 2026 report, 35% of workers worldwide work more than 48 hours a week (ILO, 2026). When shift work and long hours combine in production periods in which overtime is common, the time available for rest becomes shorter still. The fact that 66% of employees in Turkey say they experienced stress during a large part of the previous day (Gallup, 2026) is a reminder that fatigue is often carried together with a heavy stress load. For employees who take second jobs because of the cost of living, or who travel long distances to work, rest time can shrink even further.

In a large survey carried out in Europe, general fatigue comes first, at 37%, among the health problems that workers say are caused or made worse by work (EU-OSHA, 2022). Fatigue is one of the risks most often seen on the shop floor and least often talked about.

Shift Work and Workplace Accident Risk: What Does the Research Show?

According to a review examining the relationship between shift patterns and safety, productivity and safety can deteriorate at night; safety gets worse over consecutive night shifts, with increasing working hours and as the time between breaks lengthens (Folkard and Tucker, 2003). The figures reported on the basis of this review are striking:

• In an 8-hour shift system, the risk of accidents and injuries was reported to be 18.3% higher on the afternoon shift and 30.4% higher on the night shift than on the morning shift.
• Compared with the first night, the risk was found to be about 6% higher on the 2nd night, 17% higher on the 3rd and 36% higher on the 4th.
• The risk in the 12th hour of a shift was reported to be more than double the average over the first 8 hours.

These figures come from pooling different studies, largely from workplaces abroad, and cannot be applied one-to-one to every workplace; however, they clearly show which points are critical in shift planning: night hours, the number of consecutive nights, long shifts and stretches without breaks.

The picture in Turkey shows why this risk should be taken seriously. According to the Social Security Institution (SGK) data, 766,039 workplace accidents were recorded in 2025, and 1,931 people lost their lives as a result. About 41% of the accidents and about 22% of the deaths occurred in the manufacturing sector (SGK, 2026). In Çorum, 3,821 workplace accidents and 12 deaths were recorded in the same year (SGK, 2026). Independent monitoring organisations also argue that the real figures may be higher than the official records. It cannot be said that all of these accidents are related to fatigue; however, fatigue, as one of the main factors that increase human error, should be examined in every accident analysis.

Fatigue is not a character weakness; it is a safety risk that has to be managed. A "hang on a bit longer" culture can be the first step on the road to an accident.

The Psychological Dimension of Fatigue: Sleep, Stress and Burnout

Prolonged irregular sleep and a high work pace turn over time into a burden that is not only physical but psychological. Sleep problems feed anxiety and low mood, and anxiety and low mood in turn disrupt sleep further. For this reason, sleep problems should not be seen as merely a personal matter.

When chronic work stress is not managed, burnout can emerge. The WHO defines burnout not as a medical condition but as an occupational phenomenon resulting from chronic workplace stress that has not been successfully managed (WHO, 2019). According to a review of thirty-six prospective studies, burnout predicts later insomnia, depressive symptoms, absenteeism and presenteeism, as well as serious injuries (Salvagioni et al., 2017). This finding shows that burnout in a factory setting is a direct workplace safety issue. Those who are curious about the topic from an individual perspective can look at the article on burnout syndrome.

The long-term health effects of night work are also being researched. The International Agency for Research on Cancer (IARC) has classified night shift work as "probably carcinogenic to humans" (Group 2A), while noting that the evidence in humans is limited (IARC, 2020). This information matters not to create fear but to remind us that night work needs to be managed carefully together with health surveillance and shift planning.

Warning Signs of Fatigue in Shift Workers

Fatigue often goes unnoticed even by the employee themselves, or is brushed aside with "I'll get used to it". Signs that shift supervisors and foremen can watch for include:

• Yawning, rubbing the eyes, brief spells of zoning out
• A growing number of small errors and forgotten steps in routine tasks
• Slower reaction times, asking for instructions to be repeated
• Irritability, more arguments with teammates
• Frequent lateness, requests for sick leave or shift changes
• Sitting and dozing off outside break times, or relying heavily on caffeinated drinks

None of these signs alone amounts to a diagnosis; the person's circumstances at home, their health or the stress they are under can create a similar picture. What matters is that the supervisor who notices the signs approaches the employee with curiosity rather than blame. An open question such as "You've looked tired lately; is the shift pattern getting to you?" is often enough to break a long silence. If necessary, the task can be changed temporarily and the employee can be referred to the workplace physician or to a psychological support service. When short conversations like this become a habit in a shift-work setting, it also strengthens trust within the team.

The Legal Framework: Employers' Responsibilities

The psychological effects of shift work are not mentioned by name in Turkey's Occupational Health and Safety Law No. 6331, but several articles bear directly on the subject:

• Article 4(ç): When assigning tasks to employees, the employer takes into account their suitability for the work in terms of health and safety.
• Article 5(ç): The negative effects of monotonous work and production pace on health and safety must be prevented or, if they cannot be prevented, reduced to a minimum.
• Article 5(f): A prevention policy is to be developed that covers the effects of work organisation, working conditions and social relationships.
• Article 10: In the risk assessment, the situation of groups that require special policies, such as young, older, pregnant or breastfeeding employees, is taken into account.
• Article 15: The employer provides health surveillance according to the risks employees are exposed to.
• Article 17: Occupational health and safety training is renewed in line with changing and newly emerging risks. Fatigue and sleep can be added to the training content for shift workers. The same article also provides for additional training to be given to an employee who has had a workplace accident before they start work.

Article 8 of the Risk Assessment Regulation, in turn, provides that psychosocial sources of hazard must also be identified and recorded. Shift patterns and work pace are natural headings in this assessment. We explained step by step how to carry out the assessment in the article on psychosocial risk assessment.

What Employers Can Do: Concrete Steps to Reduce Fatigue in Shift Work

It may not be possible to eliminate fatigue entirely in a shift system, but with good planning and a supportive culture the risk can be managed to a significant degree.

In shift planning

• Limit the number of consecutive nights. Knowing that risk rises over consecutive nights suggests shorter rotating blocks rather than long runs of nights.
• Avoid long shifts and clusters of overtime. Long working hours, especially at night, increase the risk of attention errors.
• Give regular breaks. A longer gap between breaks harms safety; make breaks a rule that is protected against production pressure.
• Plan critical tasks. Where possible, do not leave high-risk maintenance and adjustment work for the hours of lowest alertness at night.
• Structure the shift handover. Passing on the state of the line both in writing and verbally at handover reduces information loss caused by fatigue.
• Announce the plan in advance. Sharing the shift rota a reasonable time ahead lets employees organise their sleep, family and transport accordingly. Last-minute changes are a significant source of stress that disrupts rest.
• Ask employees for their views. Listening to the employee representative and the operators on the line when making decisions about shift patterns makes it easier to find workable solutions.

In culture and communication

• Make it safe to say "I'm tired". The foundational study of psychological safety was carried out in 51 work teams in a manufacturing company and found that psychological safety was associated with learning behaviour (Edmondson, 1999). An environment in which employees who report errors and fatigue are not punished makes near-miss events visible.
• Train foremen and shift supervisors. In the WHO's guidelines on mental health at work, the recommendation with the strongest evidence is mental health training for managers (WHO, 2022). A supervisor who can recognise signs of fatigue and stress and talk to the employee is one of the most important protective factors.

In employee support

• Run sleep and stress management training. A meta-analysis of workplace stress management programmes found that cognitive-behavioural programmes had a larger effect than other approaches (Richardson and Rothstein, 2008). Group training backed by reinforcement sessions should be preferred to one-off seminars.
• Offer confidential individual support. Being able to reach a specialist with whom they can talk about sleep, family and stress problems helps employees address them before they grow. We discussed how such a structure can be set up in the article on the employee assistance programme.

How to Get Started in Your Organisation

Fatigue management in a workplace with shift work can be planned in three stages:

1. Needs analysis: Examine your accident and near-miss records broken down by shift, time of day and number of consecutive days. Compare the intensity of overtime, absence and resignations by department. Run a short anonymous survey of employees on sleep, fatigue and the shift pattern.
2. Programme: Based on the findings, identify the changes that can be made to the shift plan, supervisor training, sleep and stress management work, and individual support options. Give priority to organisational measures aimed at the source; individual support complements these measures.
3. Measurement: Re-evaluate accident and near-miss numbers, absence, resignations and survey results at regular intervals, and monitor the effect of changes made to the shift plan.

You can look at the training and consultancy options suited to your factory and shift pattern on the corporate services page.

Frequently Asked Questions

Does night shift work really increase accident risk?

Research shows that accident risk rises at night and over consecutive night shifts. One review reported that in an 8-hour system, the risk on the night shift was about 30% higher than on the morning shift. For this reason, night work needs special attention in planning.

Why do shift workers need psychological support?

Irregular sleep, social and family disconnection and a high work pace can, over time, lay the ground for anxiety, anger and burnout. These symptoms affect both the employee's quality of life and their attention and safety. Early support makes it easier to address problems before they grow.

Can fatigue be reduced without changing the shift plan?

Steps such as protecting breaks, planning critical tasks, supervisor training and sleep training can make a difference. However, if a significant part of the risk comes from the plan itself, the shift pattern also needs to be reviewed for lasting improvement.

Is sleep training enough on its own?

No. Sleep and stress management training can be useful, but its effects may fade over time and it does not replace organisational measures. Healthier results are achieved when training is applied together with shift planning, a break routine and a supportive management culture.

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Eda Erkan Alapala

Klinik Psikolog. İstanbul Kent Üniversitesi Klinik Psikoloji Tezli Yüksek Lisans mezunu; bilişsel davranışçı terapi, çocuk merkezli oyun terapisi ve çocuk-ergen psikoterapisi alanlarında eğitimlerini tamamlamıştır.

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