Shift Work and Long Work Hours By : Dr. Ar. Safaeian Occupational medicine specialist

Shift work  Shift work involves work at times other than daytime hours of approximately 7:00 A.M. to 6:00 P.M.  Almost 15% of full-time workers (or 15 million Americans) work on evening, night, rotating, split, or employer-arranged irregular shifts  Social needs and economic factors promote the use of shift work and long hours.

Critical services with shift work 1. police 2. fire protection 3. health care 4. transportation 5. communications 6. public utilities 7. military service 8. industries require continuous processing

Shift Work Schedules  What is the best or worst work schedule? ☻There is no simple answer to this question because there is no ideal schedule that fits every situation. ☻Both good and bad points can be found in most work schedules.

Types of Work Schedules  Different schedules might be used by the same occupation, the same industry, or even the same workplace.  5 days on a single shift followed by 2 days off (max).  Depending on the job, it is even possible to work 7, 10, or 14 days in a row. ☻Offshore oil rig workers, might work 2 weeks out on the rig followed by 2 weeks off at home. ☻Offshore oil rig workers, might work 2 weeks out on the rig followed by 2 weeks off at home.

Time of Shift  24 hour operations usually are divided into 2 or 3 shifts.  Start- and end-times depend on the length of the shift. ☻Day shift (also called morning or first shift) starts around 5 to 8 a.m. and ends around 2 to 6 p.m. ☻Evening shift (also called afternoon or second shift) starts around 2 to 6 p.m. and ends around 10 p.m. to 2 a.m. ☻Night shift (also called third, “graveyard,” or “mid” shift) starts around 10 p.m. to 2 a.m. and ends around 5 to 8 a.m.

 2nd-shift worker efficiency levels are typically 3–5% below 1st shift  3rd shift 4–6% below 2nd shift  The productivity level, i.e. cost per employee, is often 25% to 40% lower on 2nd and 3rd shifts due to fixed costs which are "paid" by the first shift.

Permanent versus Rotating Schedules:  Permanent : ☻Most permanent night workers never really get used to the schedule. Fatigue occurs because most night workers go back to a day schedule on their days off. Fatigue occurs because most night workers go back to a day schedule on their days off. They sleep less during the day, so they don’t recover from fatigue. They sleep less during the day, so they don’t recover from fatigue. Over several days, fatigue can accumulate to unsafe levels. Over several days, fatigue can accumulate to unsafe levels.

 Rotating : ☻Often used because they are considered fairer to all workers ☻ they can never completely adapt to a set work schedule.

Speed and Direction of Rotation:  Speed : ●the number of consecutive day, evening, or night shifts before a shift change occurs. ●the number of consecutive day, evening, or night shifts before a shift change occurs.  Direction : ●Forward rotation, from day to evening to night shift. ●Forward rotation, from day to evening to night shift. ●Backward rotation, from day to night to evening shift. ●Backward rotation, from day to night to evening shift.

SPEED OF ROTATION  Longer rotations (3-4weeks of working the same hours) allow workers more time to get used to night shifts. However, workers usually return to a day schedule on their days off.  A fast rotation (every 2 days) allows no time to get used to night work. ☻Some researchers prefer the fast rotation, because the worker quickly pass the hard shifts and then has a couple of days off. ☻Some researchers prefer the fast rotation, because the worker quickly pass the hard shifts and then has a couple of days off. ☻Very fast rotations are used in Europe more than in America. ☻Very fast rotations are used in Europe more than in America.

DIRECTION OF ROTATION  Can affect the ability of circadian rhythms to adapt to the change in work times.  Forward rotation is better for helping a worker adjust to new sleep times(because it is easier to go to bed later and wake up later than earlier).  Backward rotations work against the body rhythm by forcing the worker to go to sleep earlier and earlier.  backward rotation schedules are used frequently in US.

Work-Rest Ratios  The more a person works, the less time he or she will have for rest.  How many breaks during the shift and the length of breaks ? -Several short breaks might be better than a few long breaks. -Several short breaks might be better than a few long breaks.  How many days works in a row

How Regular or Predictable?  Most jobs have a very regular, set schedule.  HCW, breakdown at a factory, Railroad workers  It is difficult to get adequate rest.  Maybe they are on call and never get deep, satisfying sleep because they are always listening for the phone. Some people call this “sleeping with one eye open.”

Table 1: Work Schedule Features Example Particulars Feature Day, evening or night Time of Shift Shift Rotation Fixed shift times (no rotation) Permanent Changing shift times Rotating Rapid: 2 days per shiftNumber of workdays before shift change speed Slow: 21 days per shift Clockwise: day to evening to night Clockwise (forward) or counterclockwise (backward) change direction Counter: day to night to evening

Example Particulars Feature Work-Rest Ratios 5 workdays/2 rest days 7 workdays/3 rest days Number of workdays to number of rest days Overtime workdays Weekly 8 h work/16 h rest 12 h work/12 h rest Lunch, coffee break Work hours to rest hours Rest breaks within a day Overtime work hours Daily

Example Particulars Feature How Regular or Predictable? Emergency or “on-call” part of the schedule Unplanned overtime Demand-based scheduling or working off a “call board” Can affect any other part of the schedule

Shift work The relationship between shift work and health and safety is influenced by : The relationship between shift work and health and safety is influenced by :  work schedule  the job  the worker  the work environment  others (ergonomic,organizational factors, job demands, workers' personalities, sociodemographic characteristics, geographic location, recreational resources, housing arrangements, sociometric patterns, and social support)

Risks Associated with Shift Work  Sleep, Sleepiness  Circadian Rhythms, Performance, and Safety  Social and Familial Disruptions  Long-term Effects and Vulnerable Groups

Sleep, Sleepiness  The most direct effect of shift work is the reduction in the length and quality of sleep  Night-shift workers have lighter, more fragmented, and less restful daytime sleep  Rotating shift workers obtain less sleep, than permanent schedules.  No adaptation

Circadian rhythms refer to biologic rhythms that show a cyclic rise and fall about once a day.

Circadian Rhythms, Performance, and Safety  The timing of the circadian rhythms are slow to change and generally take several days to readjust after abrupt  Disturbances in circadian rhythms lead to reductions in the length and quality of sleep, increase negative, GI symptoms  Injury risk increased :18% during afternoon/evening shift and 34% during the night

Social and Familial Disruptions  Shift workers often work in the evening and sleep during the day  The disruptions depend on: worker's schedule, family, gender of the worker, presence of children, the degree of flexibility in the worker's social contacts and leisure pursuits.

Long-term Effects  32% of night workers and 26% of rotating shift workers experience long-term insomnia and excessive sleepiness and are unable to adapt their sleep adequately on these shifts.

Vulnerable Groups  Unstable angina or MI  HTN requiring regular medications  IDDM  Asthma requiring regular medication  Psychiatric illnesses requiring regular medication  Alcohol or drug abuse  GI diseases  Sleep disorders  Epilepsy requiring medication within the past year  Renal impairment  Thyroid and suprarenal pathologies  Malignant tumors  Pregnancy

Long-term Effects  Aging is associated with less tolerance of shift work  The sleep changes may begin as early as the 30s and 40s, so some workers who initially adapted well to shift work during their younger years may show more symptoms as they grow older

Long Work Hours  Working a minimum of 50 hours per week  Estimated that over 26% of U.S. men and 11% of U.S. women worked long hours in 2000.

Risks Associated with Long Work Hours The overtime work is associated with small but significant increases in adverse physical and psychological outcomes like: The overtime work is associated with small but significant increases in adverse physical and psychological outcomes like:  poorer perceived general health  increased injury rates  more illnesses  increased mortality

Countermeasures Efforts to promote adaptation to or ease the difficulties of coping with shift work and long work hours include Efforts to promote adaptation to or ease the difficulties of coping with shift work and long work hours include  strategies for employers  strategies for workers

Countermeasures  Work schedules /rest breaks during work  Sleep strategies  Altering circadian rhythms (bright or blue light)  Optimally timing physical activity  Improving physical conditioning  Pharmacologic aids or using caffeine  Dietary regimens  Stress reduction techniques  Social support groups  Providing family counseling.