Shift Work

Types of Shift Work

• Shift work includes various schedules outside standard daytime hours:

• Afternoon shifts

• Night shifts

• Weekend shifts

• Extended work periods:

• Shifts that last 12 hours or more

• Rotating hours:

• Different start and end times on different days

• Split shifts:

• Work periods divided into two distinct parts with breaks in between

• Overtime and on-call duties

• Shift work is defined as organizing daily working hours so that teams work in succession to cover 24 hours. Standard daytime hours are generally considered to be an 8-hour work schedule between 7 AM and 7 PM, with a break for lunch.

European Union Regulations

• European Union Directive 2003/88/EC outlines safety and health requirements for working time:

• 48-hour weekly limit on working time (including overtime)

• Minimum 11 consecutive hours of rest per 24-hour period

• Minimum 24 hours of uninterrupted rest per week

• Limit of 8 hours of night work for jobs with special hazards or heavy strain

• Special provisions for sectors like transportation and offshore work

Employee Fatigue and Shift Work

• A common issue is fatigue from working three consecutive night shifts.

• Employees feel particularly tired on the third night shift, which may lead to cognitive mistakes due to insufficient recovery time before returning to day shifts, often leading to absenteeism.

• Types of shift work are varied, including nonstandard hours, rotating, extended, overtime, and on-call duties.

• Workers aged 18-29 are most likely to be involved in shift work, particularly in protective service occupations.

• Most regions have laws limiting weekly working hours to minimize health risks associated with shift work.

Health Risks Associated with Shift Work

• Lack of balance in shift hours can lead to fatigue, with disparate hours worked across consecutive weeks.

• Shift work, particularly night shifts, has been classified by the IARC as "probably carcinogenic to humans" (Group 2A).

• Connections have been noted between night shifts and higher risks of breast cancer, particularly in nurses and flight attendants.

• Associated risks include:

• Menstrual disorders

• Miscarriages

• Preterm births

• Negative mood

• Reduced communication

• Poor memory and attention

• Impaired problem-solving

• Increased risk-taking

• Slowed reaction times

• Gastrointestinal illnesses (e.g., abdominal pain, gastritis, ulcers)

• Cardiovascular issues (e.g., hypertension, coronary heart disease)

• Conditions such as asthma and diabetes may worsen.

Circadian Rhythms and Biological Clocks

• Circadian rhythms regulate physical, mental, and behavioral changes in a 24-hour cycle.

• All organisms are influenced by these rhythms, which respond primarily to light.

• The biological clock is primarily located in the hypothalamus and coordinates the circadian rhythm with body systems, affecting sleep/wake cycles, cardiovascular activity, and hormone secretion.

• Fatigue-related road accidents peak early morning, especially around 2 AM, coinciding with high sleepiness.

• Optimal sleep occurs when falling asleep between 10 PM and 2 AM; difficulty sleeping is noted between 8 AM - noon and 5 PM - 9 PM, known as "forbidden zones."

Work Hours and Their Effectiveness

• Shifts longer than 12 hours can negatively impact outcomes; >40 hours/week is linked to adverse events.

• Overtime correlates with decreased job performance.

• Evidence is inconclusive regarding compressed work weeks.

• Rotating shifts tend to yield worse job performance, while fixed night shifts can allow for body clock resynchronization, although job satisfaction declines.

• Adequate rest can improve alertness and reduce fatigue, whereas quick returns to work increase fatigue risks.

Risk Assessment and Organizational Recommendations

• Employers should actively mitigate the negative impact of shift work, leading to:

• Lower sickness and absenteeism

• Reduced staff turnover

• Decreased errors and accidents

• Healthier, more productive employees

• A four-stage risk assessment process includes:

1. Establish a risk management system.

2. Assess risks in the workplace.

3. Take action to reduce the identified risks.

4. Regularly review arrangements.

Tools for Monitoring Shift Work Impact

• Epworth Sleepiness Scale (ESS): a self-administered questionnaire assessing the likelihood of dozing off in various scenarios.

• Standard Shift Work Index: a complex survey tool with >200 questions on variables relevant to shift work.

• Swedish Occupational Fatigue Inventory (SOFI): assesses subjective fatigue qualities in occupations.

Shift Work Disorder (SWD)

• Shift work disorder characterizes excessive sleepiness during wake times and insomnia at sleep times, linked solely to shift work.

• Significant sleep loss is common, averaging 1-4 hours loss per night.

• Vulnerable groups include pregnant women, young and older workers, those with health issues, and new/temporary workers.

• Optimized shift design mitigates risks; 8-hour shifts are ideal, especially for monotonous or demanding work.

• Fast shift rotation is preferable, with minimal disruption to body clocks.

Health Assessment and Managing Diabetes

• Diagnosis involves determining if sleep issues arise from shifts rather than other disorders or medical issues.

• Recommended assessments may include sleep diaries over seven days, along with possible use of actigraphy or assessments of melatonin and core body temperature.

• Health assessments aim to ensure:

• Employee fitness for night work.

• Non-adverse health effects from night work.

• Accommodations for employees with disabilities.

• Risk assessments for night work.

• Night work disrupts diabetes management, complicating maintenance of regular routines necessary for health.