Transcript Shiftwork
Outline
What is shiftwork?
Shiftwork in Canada
Why there is a need for shiftwork
Health and safety concerns of shiftwork
Circadian Rhythm
Optimal shift scheduling
Shift work systems
Strategies for dealing with shiftwork
Shiftwork
A shift worker is anyone who follows a work schedule
that is outside of the typical "9 to 5" business day
National Sleep Foundation
Shiftwork differs from a “normal” work day in two ways:
Work is performed regularly during times other than morning
and afternoon
2) At a given workplace, more than one shift is worked during the
24-hour day
A shift often lasts 8 hours but may be shorter or longer
1)
Approximately 25% of the North American working
population work shiftwork
CCOHS stat
Shiftwork in Canada
In 2005, the General Social Survey conducted by
Statistics Canada found that 28% of employed
Canadians (4.1 million workers) were shift workers
82% worked full time (>30 hrs/week)
Shiftwork in Canada
In 2005, women accounted for only 37% of full time
shift workers, but made up 69% of part time shift
workers
Men made up 57% of the total number of workers who
do shift work (all full- and part-time)
Shiftwork in Canada
In 2005, rotating shifts and irregular schedules were
the most common types of shift work, accounting for
2.3 million full-time workers
Even though these are considered among the most
difficult shifts because the body cannot properly adjust
to the sleep pattern changes, rotating child care is
difficult to find and health effects can be profound
Types of Shiftwork in Canada
Shiftwork is not new!
Deliveries were made in ancient Rome at night in order to
relieve street congestion
Bakers habitually work through the late night hours
Soldiers and firefighters have always been accustomed to
night shifts
With industrialization came long working days with teams
of workers relaying each other to maintain blast furnaces,
rolling mills, glassworks, and other workplaces where
continuous operations were required
Who works shiftwork
Traditionally: shift work was required to provide vital services and emergency cover at
all hours of the day and night and also to maintain long-term industrial processes
Today: Shiftwork is found in financial and retail services where employees deliver
services around the clock , supermarkets, newsroom and banks, call centres
Why the need for shiftwork?
The need for "around the- clock" workers has
increased dramatically in industry during recent years
This reliance may be attributed to three main sources,
namely technological, economic and social
advancements
Economically: utilization of equipment/resources
If equipment is available 168 h per week and used for only 8h a
day for 5 days a week gives only 24% utilization
Socially: convenience (24-hour shopping, restaurants,
movies)
Why is shiftwork a problem?
The problems associated with shiftwork fall under three
areas:
1) Economic: people tend to dislike shiftwork which
may require extra pay for workers
2) Social: many workers feel that shiftwork disrupts
their personal and family life
3) Health and Safety: Rotating shifts have been
blamed for the “human error” involved with nuclear
power plants incidents, airplane accidents, and other
catastrophic accidents
Individual health factors
The Interaction Between Personal
Factors and Shiftwork
“Some of the most serious and persistent problems shift workers face are frequent sleep
disturbance and associated excessive sleepiness, which can lead to poor concentration,
absenteeism, accidents, errors, injuries, and fatalities. The issue becomes more
alarming when you consider that shift workers are often employed in the most
dangerous of jobs, such as firefighting, emergency medical services, law enforcement
and security”
- National Sleep Foundation
Individual Health and Shiftwork
Frequently changing work
schedules can lead to:
Shiftwork may also be
independent predictor of
Increased risk of insomnia
Increased body mass
Chronic fatigue
Increased body mass index
Anxiety and depression
Prevalence of obesity
Cardiovascular and
Waist-to-hip ratio
gastrointestinal problems
Impaired reproduction in
women
Circadian rhythm
disruption
Atkinson et al. (2008)
Fatigue Symptoms
Sleepiness
Irritability
Increased
susceptibility to illness
Depression
Reduced alertness,
concentration and
memory
Lack of motivation
Headaches
Giddiness
Loss of appetite and
digestive problems
Personal Factors
Many functions of the human body have long been
recognized to exhibit periodic variations
Of concern are those fluctuations which occur on a
daily basis called circadian rhythms
Among those body functions which show diurnal
variations:
Sleep
Readiness to work
autonomic processes
heart rate
body temperature
Blood pressure
Circadian Rhythms
Circadian Rhythms
Circadian comes from the Latin word “circa dies”
which means “about a day.”
Many human physical functions follow these daily
rhythms or 24-25 hour cycles
Sleeping, walking, digestion, secretion of adrenalin,
body temperature, blood pressure, pulse, other body
functions
The body uses cues from its processes and from the
environment such as clock time, social activities, the
light/dark cycle, and meal times to keep the various
rhythms on track
Circadian Rhythms
Involvement in shiftwork, in particular night work,
results in a disruption of these inherent rhythms.
These phase shifts occur slowly over a considerable
period.
Some people can start to adapt after 2-3 days while some
take much longer.
Adjustment on “days off” does not happen because
most individuals go back to normal day schedules
Circadian Rhythms
• Circadian rhythm phase shifts induced by shiftwork
can have significant effects on the worker in terms of:
•
•
•
•
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performance efficiency
motivation
sleep patterns
family and social life
health
Shiftwork Disorder
Shift work sleep disorder is a circadian rhythm sleep
disorder
The main complaint for people with shift work sleep
disorder is excessive sleepiness. Other symptoms
include:
Insomnia
Disrupted sleep schedules
Reduced performance
Difficulties with personal relationships
Irritability/depressed mood
Circadian Type
There are 2 broad classifications of personality
associated with circadian type which are differentiated
between the “morning larks” and the “night owls”:
1)Morning types (M-types) aka larks:
Have early bedtimes & wake times and
are more alert in the morning hours
2)Evening types (E-types) aka owls:
Are more aroused later at night and
experience difficulty waking up early
Circadian Type & Shiftwork
M-types have been found to be less tolerant of night
shift for 3 reasons:
1.
They find it extremely hard to stay awake at night, or
to sleep late in the morning (standard night worker behaviors)
2. They appear to be more susceptible to environmental
zeitgebers (time cues)
3.
When M-types are isolated from all time cues, they exhibit
"free-running" circadian rhythms with an approximate length
of 24.3 hours in comparison to E-types who tend to have slower
rhythms of approximately 25.5 hours
Circadian Type & Shiftwork
Night work is best suited to those individuals with a
longer running period as this leads to a phase delay in
behaviour (i.e.- a later bedtime)
It has been questioned whether morningness-
eveningness is a stable, genetically determined trait, or
simply a reflection of a recently developed habit
Example: An M-type individual could temporarily
acquire E-type characteristics, but may revert back to
their morningness tendency at a later stage
Shift Scheduling
What is the most optimal shift
schedule?
1) There is no “golden” schedule that fits every
operation’s needs
2) The schedules that perform the best:
1)
balances operational requirements, employee
preferences and lifestyle issues, and takes into account
the human factors considerations that influence safety
and employee performance
3) The best schedules can only be achieved by involving
the employees in the shift schedule selection process
Why involve employees in shiftwork
scheduling?
Through education, participatory design, and group
implementation of employee involvement in schedule
design/redesign financial and performance benefits
increase substantially compared to schedules decided by
management alone
Resulting in:
Better employee morale and satisfaction with scheduling
Lower absenteeism and turnover
Increased operational efficiency
Improved daytime sleep quality
Decreased physical and
psychological circadian
General Notes on Scheduling
An early morning start (before 7:00am) for the
morning shift should be avoided
Shifts should rotate forward:
The schedule should be simple and predictable –
people want to plan their lives!
Shift Systems
Four Important Questions Regarding
the Features of Shift Systems
Does a shift extend into hours that would be
normally be spent asleep?
2. Is the shift worked throughout the entire seven-day
week, or does it include days of rest, such as a free
weekend?
3. Into how many shifts are the daily work hours
divided? Are there two, three, or more shifts per day?
4. Do the shift crews rotate or do they work the same
shifts permanently?
1.
Kogi (1985)
Other Important Features of Shift
Systems
The starting and ending time of a shift
The number of workdays in each week
The hours of work in each week
The number of shift teams
The number of free days per week or per rotation cycle
The number of consecutive days on the same shift,
which may be a fixed or variable number
The schedule by which an individual works or has a
free day or days
Types of Shift Systems
Rotational shiftwork
Rapidly rotating shift systems
weekly/monthly rotating systems
Permanent night shift systems
Rotational Shiftwork
Shifts rotate or change according to a set schedule
Shifts can be continuous (24/7) or semi-continuous (2-
3 shifts/day without weekends)
Workers take turns working all of the shifts in the
system
Rapidly Rotating Systems
Switches once or twice during a week
Found to cause the least disturbance to the
endogenous body clock
Weekly/Monthly Rotating Systems
Changes every week or every month
• Provide for both the physical and social needs of
the worker
A forward direction (morning-afternoon/eveningnight) is preferred for shift rotation
• Means minimum disturbance of diurnal rhythms
Weekly/Monthly Rotating Systems
Weekly rotating shifts are generally regarded as
being the worst system
• Because disruptions to the circadian rhythms lead
to a cumulative sleep debt
• These systems tend to be the most commonly used
(employment equity)
Permanent Night Shift System
An acceptable level of circadian rhythm
adjustment can normally be achieved with this
shift system
This nocturnal orientation may in turn improve
sleep and performance
Permanent night shifts are preferred when safety is
crucial
Permanent Night Shift System
Family units appear to prefer permanent night
work as it facilitates the organization of domestic
responsibilities
Some individuals working this shift feel socially
isolated
Extended Workdays
One further variable to consider in terms of the
design of shift systems is that of the length of the
shift
Some suggest a shift should not exceed 8 hours
(except where the work is low in physical and
mental demands) while others recommended that
extended work periods of 9 to 12 hours may be
acceptable
Advantages of twelve hour shifts
Management Perspective
Increased productivity,
reduced errors
Increased continuity and
accountability
Reduced adaptation time
Higher project completion
rates
Reduced absenteeism
Lower attrition and turnover
Improved morale
“Dedicated” employees
Employee Perspective
More days off
Longer/better breaks
Few consecutive days worked
Less commuting required
Twice as many weekends off
Improved family & social life
Improved Morale
More home study time
More frequent “recovery” days
Better use of vacation time
Better utilization of personal time
Elimination of double
shifts/holdovers
Elimination of evening shifts
Disadvantages of 12 Hour Shifts
Employee Perspective
Management Perspective
Harder to sustain vigilance
Potential comprise in alertness
and performance
Increased exposure to work
related stress
Diminished communication or
personal interaction
Unequal distribution of work
hours
Increased risk of getting “out of
touch”
Increased “moonlighting”
Increased ergonomic risk
More difficult absence coverage
Difficulties of change
Limited social time during work days
Sleep schedule inflexibility
Irregular pay weeks
Concerns of older workers
Reduced tolerance of long commutes
Difficult to schedule meetings
Decreased tolerance to physically
demanding jobs
Pay loss when day is missed
Driver fatigue
Fast-rotating 12-hour schedules
Longer hours away from home in
evenings
Increased percentage of night shifts
Summary of Features for 8 and 12Hour Shift Schedule
Strategies for Improving Problems
Associated with Shiftwork
Most obvious solution?
There are two basic levels where improvements can be
made:
1) The organizational level - primarily through the
design of shift schedules, education and better
facilities.
2) The individual level - helping workers to get better
sleep, a healthier diet, and the reduction of stress.
Organizational Approaches
Talk to employees to see shift preferences
Consider time at which shift starts/ends
Provide time off during socially advantages times
Let employees know schedules well in advance
Allow some flexibility for staff to switch shifts but
make sure people aren’t double-shifting
Provide same facilities & support for all shifts
Organizational Approaches
Educate employees on how to cope with shiftwork
Consider exposure limits, breaks required
Consider different lengths for shifts
Keep schedule regular and predictable
Keep long shifts and overtime to a minimum
Plan for some weekends or holidays off
Good Practice Guidelines for the
Work Environment
Adequate lighting & proper heating
Same facilities available for each shift
Access to healthy meals
Encourage interaction between employees
Keep in contact about employees about their
concerns
Encourage exercise
Encourage breaks when sleepy
Individual Approaches
Pay attention to food/nutrition
Exercise
Figure out how to optimize sleep time
Get information on shiftwork health risks
Have a social life
Seek advice from doctor if you have health
conditions
Take more frequent breaks when fatigued
Individual Approaches
Talk to family and friends about sleep schedule
Restrict or avoid caffeine, cigarettes and alcohol
consumption
Avoid long commutes when sleepy
Use co-workers to keep you awake on the job
Talk to co-workers for tips on how to cope
Don’t leave the boring tasks for the end of the shift
when most fatigued
Try not to alter sleep schedule too much on “days
off”
References:
Atkinson, G., Fulick, S., Grindey, C., & Maclaren, D. (2008). Exercise, energy balance and the shift
worker. Sports Medicine, 38(8), 671-685.
Canadian Centre for Occupational Health and Safety. (2007). Rotational Shiftwork. Retreived from:
http://www.ccohs.ca/oshanswers/ergonomics/shiftwrk.html
Carex Canada. (2008) Carcinogen profile: Shiftwork. IARC Monograph, 98. Retrieved from:
http://www.carexcanada.ca/en/shiftwork.pdf
Davis, W., & Aguirre, A. (n.d). Shift scheduling and employee involvement: the key to successful
schedules. Retrieved from: http:// www.circadian.com
The National Sleep Foundation. (2009). Shift work and sleep. Retrieved from:
http://www.sleepfoundation.org/
Konz, S., & Johnson, S.(2000). Work Design: Industrial Ergonomics. Scottsdale, Az: Holcomb
Hathaway.
Kroemer, K., Kroemer, H., & Kroemer-Elbert, K. (2001). Ergonomics: How to design for ease and
efficiency (2nd ed.). Upper Saddle River, NJ: Prentice Hall.
Moore-Ede, M., Davis, W., & Sirois, W. (n.d). Advantages and Disadvantages of twelve-hour shifts: A
balanced perspective. Retrieved from: http://www.circadian.com
Occupational Safety and Health Branch, Labour Department.(n.d) Guide on shiftwork. Retrieved
from: http://www.labour.gov.hk/eng/public/oh/ShiftWork.pdf
Williams, C. (2008) Work-life balance of shift workers. Statistics Canada Catologue number (75-001X). http://www.statcan.gc.ca/pub/75-001-x/2008108/pdf/5215218-eng.pdf