Copyright Circadian Technologies, Inc. 2002
Myths and Realities of FatigueMyths and Realities of Fatigue
Circadian Technologies, Inc.Circadian Technologies, Inc.24 Hartwell Ave.24 Hartwell Ave.
Lexington, MA 02421Lexington, MA 02421Phone: 781-676-6900Phone: 781-676-6900
Fax: 781-676-6999Fax: 781-676-6999Web: www.circadian.comWeb: www.circadian.com
Copyright Circadian Technologies, Inc. 2004
IMPACT OF FATIGUE
Copyright Circadian Technologies, Inc. 2003
Copyright Circadian Technologies, Inc. 2004
Myth or Reality?Myth or Reality?
1. Fixed shifts (e.g. always working the night shift) are safer than rotating shifts.
2. As long as its voluntary, there is no evidence that demonstrates a clear upper limit on overtime hours.
3. Tired haul truck drivers (or other operators) can anticipate the onset of fatigue and take corrective actions to avoid it?
4. Long shifts (e.g. 12-hours or more) are less safe than traditional 8-hour shifts
5. Shiftworker training can measurably impact how shiftworkers spend off-duty time and family life.
Copyright Circadian Technologies, Inc. 2004
Effects of 24/7 on Employee FatigueEffects of 24/7 on Employee Fatigue
Disrupted sleep at home
Chronic sleep deprivation
Lack of awareness of extent of sleep debt
Micro-sleep
Automatic behavior syndrome
Nodding off on the job
Reduced alertness, vigilance and performance at work
Copyright Circadian Technologies, Inc. 2004
Reports of Nodding Off at WorkReports of Nodding Off at Work
Round-the-clock workers frequently fall asleep when working the Round-the-clock workers frequently fall asleep when working the night shifts.night shifts.
18 20 22 2 4 6 8 10 12 14 16 18
Time of Day (hrs.)
Copyright Circadian Technologies, Inc. 2004
NUMBER OF HOURS AWAKE12 13 14 15 16 17 18 19 20 21 22 23 24
0.00
0.02
0.04
0.06
0.08
0.10
Adapted from Dawson and Reid, 1997
Blood Alcohol Content
Equivalence of Fatigue Impairment to Alcohol Impairment
Copyright Circadian Technologies, Inc. 2004
Human performance at many different tasks is most impaired Human performance at many different tasks is most impaired between 1 and 6 am.between 1 and 6 am.
%
10
5
0
-5
-10
-15
-20
12 15 18 21 24 03 06 09
Psychomot. Perf.
Cancellation
Digit Summation
Simulator (a)Simulator (b)
Time of Day
12
Effects of 24/7 on PerformanceEffects of 24/7 on Performance
Copyright Circadian Technologies, Inc. 2004
Costs In Extended Hours Operations Costs In Extended Hours Operations ProductivityProductivity
16
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
Noon2
PM4
PM6
PM8
PM
10 P
M
Midn
ight
2 AM
4 AM
6 AM
8 AM
10 A
M
Time of Day
Rel
ativ
e E
ffic
ien
cy
30
35
40
45
50
55
60
40 45 50 55 60 65 70
Hours Worked per Week
Pro
du
ctiv
e H
ou
rs p
er W
eek
Study A
Study B
Study C
Study D
Productivity decreases at night by 5%. This equates to $3,300, or $79.4 billion a year
Study A shows productive hours when a person is excessively fatigued (burnout). Study B is after working 4 weeks of long hours. Studies C and D are from just 1 week of long hours.
Copyright Circadian Technologies, Inc. 2004
12
34
56
78
0:00-8:00
8:00-16:00
16:00-0:000
2000
4000
6000
8000
10000
12000
0:00-8:00 8:00-16:00 16:00-0:00
Business Costs: Average Tonnage by Time of Business Costs: Average Tonnage by Time of DayDay
Copyright Circadian Technologies, Inc. 2004
Results of Improvement in Nightshift Results of Improvement in Nightshift Performance AlonePerformance Alone
Total Tonnage on Nightshift:Total Tonnage on Nightshift:(Current)(Current)
Total Tonnage on Nightshift:Total Tonnage on Nightshift:(Minimizing 4:00am dip)(Minimizing 4:00am dip)
Total IncreaseTotal Increase::
1,971,702 tons
2,023,896 tons
52,194 tons=3% improvement for nightshift=1% increase in total tonnage
ADDITIONAL 3.29 DAYS OF PRODUCTION/YEAR
Copyright Circadian Technologies, Inc. 2004
Trends In Extended Hours Operations Health Care Costs
3-4 times higher rate of 3-4 times higher rate of Obstructive Sleep ApneaObstructive Sleep Apnea
2-3 times greater rate of 2-3 times greater rate of Gastrointestinal DisordersGastrointestinal Disorders
2-3 times increased rate of 2-3 times increased rate of Cardiovascular DiseaseCardiovascular Disease
1.5-2 times more 1.5-2 times more Musculoskeletal ProblemsMusculoskeletal Problems
Probable increased risk of Probable increased risk of Mental Health IllnessesMental Health Illnesses
2-3 times higher overall 2-3 times higher overall Health and Wellness CostsHealth and Wellness Costs
18
Copyright Circadian Technologies, Inc. 2004
Trends In Extended Hours Operations Accidents and Injuries
19
Workers comp claims 20% higher in shiftwork Workers comp claims 20% higher in shiftwork operationsoperations
29% of extended hours employees fell asleep several 29% of extended hours employees fell asleep several or more times a week while at work.or more times a week while at work.
Workers' Comp and Fatigue Levels
$0
$1,000
$2,000
$3,000
$4,000
$5,000
No Fatigue Low Fatigue ModerateFatigue
High Fatigue
Copyright Circadian Technologies, Inc. 2004
Trends In Extended Hours Operations Trends In Extended Hours Operations Accidents and InjuriesAccidents and Injuries
0.9
1
1.1
1.2
1.3
1.4
Morning Afternoon Night
Shift
Rel
ativ
e A
ccid
ent
Ris
k
$0
$4,000
$8,000
$12,000
$16,000
Av
era
ge
Co
st
of
Ac
cid
en
ts a
nd
In
juri
es
Relative risk of Relative risk of accidents and injuries accidents and injuries on different shifts on different shifts collated from five collated from five independent studies independent studies
Increased cost of Increased cost of nightshift nightshift accidents based accidents based on insurance on insurance company claims company claims datadata
HUMAN DESIGN SPECIFICATIONS
Copyright Circadian Technologies, Inc. 2004
Copyright Circadian Technologies, Inc. 2004
Design Specs of the Human MachineDesign Specs of the Human Machine
Humans were not designed forHumans were not designed forpeak performance at nightpeak performance at night
Copyright Circadian Technologies, Inc. 2004
Well Established Scientific Research on Well Established Scientific Research on Biological ClocksBiological Clocks
HypothalamusCerebral Cortex
Brain Stem
Spinal Cord
Pituitary
Optic NerveEye
SCN
Source: Circadian Technologies, Inc. (1981)
Suprachiasmatic Nucleus (SCN)
Copyright Circadian Technologies, Inc. 2004
Circadian Rhythm of Performance Over a Circadian Rhythm of Performance Over a 24-Hour Period24-Hour Period
Whether we are awake or asleep, body functions continue to follow their Whether we are awake or asleep, body functions continue to follow their Circadian rhythmsCircadian rhythms
BodyCore
Temperature
98.5
96.5
11 pm 7 am 11 pm 7 am
ThermostatDown
ThermostatUp
ThermostatDown
ThermostatUp
Sleep No Sleep
MaximumSleepiness
Dusk Dawn Dusk Dawn
Copyright Circadian Technologies, Inc. 2004
Circadian Rhythm of Human AlertnessCircadian Rhythm of Human Alertness
Full Alertness
Reduced Alertness
Drowsy
20
15
5
0
Alertness Level
(MSLT)
12 15 18 21 24 03 06 09 12
Time of Day
Source: Circadian Technologies, Inc. (1993)
10
Moderate Alertness
This is an average composite for all Circadian types. The curve can be shifted 1-2 hours in either direction depending on whether one is an early or late riser, etc.
(With Normal Quantity / Quality of Nighttime Sleep)
Copyright Circadian Technologies, Inc. 2004
Determinants of Human Alertness: Determinants of Human Alertness: Extended Hours Without SleepExtended Hours Without Sleep
Full Alertness
Moderate Alertness
Reduced Alertness
Drowsy
20
15
10
5
0
Alertness Level
(MSLT)
0
Successive Hours of Sleep Deprivation5 10 15 20 25
12 15 18 21 24 03 06 0909
Time of Day
Source: Circadian Technologies, Inc. (1993)
Copyright Circadian Technologies, Inc. 2004
IMPACT ON SCHEDULING
Copyright Circadian Technologies, Inc. 2003
Copyright Circadian Technologies, Inc. 2004
Determinants of Human Alertness - Determinants of Human Alertness - Consecutive Nights on DutyConsecutive Nights on Duty
FullAlertness
ModerateAlertness
Reduced Alertness
Drowsy
20
15
10
5
0
Time of Night
22 24 2 4 6
Night 6
Night 3
Night 1
Night 2
Source: Circadian Technologies, Inc. (1993)
Alertness Level
(MSLT)
Copyright Circadian Technologies, Inc. 2004
A “Free-Running” Circadian Rhythm When External A “Free-Running” Circadian Rhythm When External Time Cues (Zeitgebers) Are RemovedTime Cues (Zeitgebers) Are Removed
When we are isolated from time cues, our internal biological clocks run on a 25 to 25.5 hour cycle. This When we are isolated from time cues, our internal biological clocks run on a 25 to 25.5 hour cycle. This is why they are “entrained “ or reset by the light of each day to keep our circadian rhythms on a precise is why they are “entrained “ or reset by the light of each day to keep our circadian rhythms on a precise 24-hour cycle. That is why it is easier to shift forward to a later time than backward to an earlier 24-hour cycle. That is why it is easier to shift forward to a later time than backward to an earlier schedule, and why forward or clockwise schedule rotations are physiologically less stressful to work. schedule, and why forward or clockwise schedule rotations are physiologically less stressful to work.
Day
1
2
3
4
5
6
7
8
9
etc.
24 08 16 241204 20
Copyright Circadian Technologies, Inc. 2004
Bio-Compatible SchedulesBio-Compatible Schedules(Physiological Design Criteria)(Physiological Design Criteria)
Bio-compatible schedules have the proper:
Rotation direction: forward
Rotation speed: slow or fixed
Shift start time: 7:00-8:00 am
Maximum schedule regularity
Minimum consecutive shifts worked
Maximum rest/recovery breaks between shift turns (48-hours min.)
Periodic long breaks (3-4 days minimum)
Minimum sleep (night shift) transitions
Copyright Circadian Technologies, Inc. 2004
Direction of Shift Rotation Preferred by Direction of Shift Rotation Preferred by Workers Who Have Experienced BothWorkers Who Have Experienced Both
80 60 40 20 0 20 40 60 80
Counterclockwise
18%
Clockwise
67%
(14% stated no preference)
Source: Circadian Technologies, Inc. (1993)
Copyright Circadian Technologies, Inc. 2004
Fatigue and Alertness FactorsFatigue and Alertness Factors
8-Hour Schedules: Work more shifts Fewer rest and recovery days, less often More cumulative fatigue / sleep deprivation Shorter work day
12-Hour Schedules Work fewer shifts in a row (i.e., 2-4) More rest and recovery days, more often Less cumulative fatigue / sleep deprivation Twice as many days / weekends off Longer, harder work day
Combination 8 & 12-Hour Schedules Compromise between 8 and 12-hour shifts
Copyright Circadian Technologies, Inc. 2004
How Physically Demanding Is Your Shift?How Physically Demanding Is Your Shift?P
erce
nt
of
Peo
ple
7 day, 8-hr schedule(7-2, 7-2, 7-3)
7 day, 12-hr schedule(2-2, 3-2, 2-3)
VeryLight
Light Moderate Heavy VeryHeavy
0
10
20
30
40
50
60
10.5 10.8 8.114.2
50.8 50
20.217.6
10.5 7.4
Copyright Circadian Technologies, Inc. 2004
How Mentally Demanding Is Your Shift?How Mentally Demanding Is Your Shift?
0
5
10
15
20
25
30
35
40
Per
cen
t o
f P
eop
le
Not at All Slightly Moderately Demanding Very
7.5
1113.3
17.8
37.5
32.1
20.8
24
20.8
15.1
7 day, 8-hr schedule(7-2, 7-2, 7-3)
7 day, 12-hr schedule(2-2, 3-2, 2-3)
Copyright Circadian Technologies, Inc. 2004
How Fatiguing Is Your Shift?How Fatiguing Is Your Shift?P
erce
nt
of
Peo
ple
0
10
20
30
40
50
60
6.5 6.29.7 8.3
50.8
46.2
2528.3
8.111
Not at All Slightly Moderately Fatiguing Very Fatiguing
7 day, 8-hr schedule(7-2, 7-2, 7-3)
7 day, 12-hr schedule(2-2, 3-2, 2-3)
Copyright Circadian Technologies, Inc. 2004
How Boring Is Your Shift?How Boring Is Your Shift?
0
5
10
15
20
25
30
35
40
45
50
41
46
27.1
18.2
21.3
16.2
4.1
12.2
6.6 7.4
Per
cen
t o
f P
eop
le
Not At All Slightly Moderately Boring Very Boring
7 day, 8-hr schedule(7-2, 7-2, 7-3)
7 day, 12-hr schedule(2-2, 3-2, 2-3)
Copyright Circadian Technologies, Inc. 2004
Case Study A: Mining and Chemical CompanyCase Study A: Mining and Chemical Company
Problem:Problem:
Low ProductivityLow Productivity
High Injury RatesHigh Injury Rates
High Employee TurnoverHigh Employee Turnover
High Medical CostsHigh Medical Costs
Low Employee MoraleLow Employee Morale
Copyright Circadian Technologies, Inc. 2004
Case Study A: Large Mining and Chemical Case Study A: Large Mining and Chemical CompanyCompany
Result of Shift Schedule Optimization:
Benefit: $800,000 increased net profit in Year One
ROI:8:1 (first year)
ScheduleSatisfaction
Index
Health IndexPersonnelTurnover Worker
Productivity inManual
Operations
PlantProductivity in
ProcessOperations
S1
87%
28%
-34%
22%13%
-40%
-20%
0%
20%
40%
60%
80%
100%
Copyright Circadian Technologies, Inc. 2004
IMPACT ON ACCIDENT PREVENTION
Copyright Circadian Technologies, Inc. 2003
Copyright Circadian Technologies, Inc. 2004
Fatigue-Related Human ErrorFatigue-Related Human Error
Inattention / lack of vigilanceInattention / lack of vigilance
Impaired judgment / lack of awarenessImpaired judgment / lack of awareness
Carelessness / lack of precautionCarelessness / lack of precaution
Failure to follow proceduresFailure to follow procedures
Miscommunication / misunderstandingMiscommunication / misunderstanding
Inappropriate / slow responseInappropriate / slow response
Microsleep / automatic behavior syndromeMicrosleep / automatic behavior syndrome
Chemical impairment (drugs, alcohol, medication)Chemical impairment (drugs, alcohol, medication)
TRACK FATIGUE FACTORS IN REPORTING SYSTEMS!TRACK FATIGUE FACTORS IN REPORTING SYSTEMS!
Copyright Circadian Technologies, Inc. 2004
Fatigue Related Driving AccidentsFatigue Related Driving Accidents
6 times greater for night shift workers
2 times greater for rotating shift workers
Other high risk factors
Working more than one job
Getting less than 6 hours sleep
Being awake more than 20 hours straight
Driving between midnight and 6:00 am
Sources: AAA Study, J. Stutts, UNC 1999
Copyright Circadian Technologies, Inc. 2004
MicrosleepMicrosleep
Short bursts of sleep wavesShort bursts of sleep waves
Seconds or minutes longSeconds or minutes long
Eyelid blinking slows downEyelid blinking slows down
Often precedes nodding offOften precedes nodding off
Loss of awarenessLoss of awareness
Fatigue/monotony inducedFatigue/monotony induced
Serious driving and work hazardSerious driving and work hazard
Copyright Circadian Technologies, Inc. 2004
Microsleeps: Potholes on the Slope of Microsleeps: Potholes on the Slope of DrowsinessDrowsiness
TOTALINCAPACITY(Eyes closed)
IMPAIREDJUDGEMENT
Microsleeps
Alertness Level
ALERTNESS
SLEEPHours of driving
Copyright Circadian Technologies, Inc. 2004
Microsleeps: Potholes on the Slope of Microsleeps: Potholes on the Slope of DrowsinessDrowsiness
TOTALINCAPACITY(Eyes closed)
IMPAIREDJUDGEMENT
Microsleeps
Alertness Level
ALERTNESS
SLEEPHours of driving
Copyright Circadian Technologies, Inc. 2004
Automatic Behavior SyndromeAutomatic Behavior Syndrome
Sleeping with eyes open
Blank stare, no eye blinking
Deep sleep (brain) waves
Loss of perception and memory
Fatigue/monotony induced
Inability to respond to changes
Major cause of driving accidents
Copyright Circadian Technologies, Inc. 2004
The Missing Factor in Optimizing 24/7 The Missing Factor in Optimizing 24/7 PerformancePerformance
Source: The Twenty Four Hour Society (1993)
Productivity
Quality
Safety
Performance Attentiveness
Aptitude Education
Training Experience
Distraction Load Work Load
Motivation
? Missing Factor
Copyright Circadian Technologies, Inc. 2004
Alertness: Alertness: The Missing Factor in Human ReliabilityThe Missing Factor in Human Reliability
Source: The Twenty Four Hour Society (1993)
Productivity
Quality
Safety
Performance Attentiveness
Aptitude Education
Training Experience
Distraction Load Work Load
Motivation
Alertness
Copyright Circadian Technologies, Inc. 2004
Results of Performance-Based Fatigue Results of Performance-Based Fatigue Management – Trucking FleetManagement – Trucking Fleet
Histogram of Fatigue Index - mean: 45.38 std_dev: 19.84 std_err: 1.45
Fatigue Index10095908580757065605550454035302520151050
Freq
uenc
y in
Per
cent
8
7
6
5
4
3
2
1
0
Histogram of Fatigue Index - mean: 28.98 std_dev: 17.81 std_err: 1.25
Fatigue Index10095908580757065605550454035302520151050
Fre
quen
cy in
Per
cent
8
7
6
5
4
3
2
1
0
BeforeBefore
AfterAfter
Fatigue ScoresFatigue Scores
AccidentAccident RateRate
2.3/mm2.3/mm
AccidentAccident RateRate
1.7/mm1.7/mm
23%
AccidentAccident Avg. CostAvg. Cost$14,100$14,100
AccidentAccident Avg. CostAvg. Cost
$4,800$4,800
66%*
*p< 0.05
Χ2=68.1P<0.0001
$32,430 / million miles
$8,160 / million miles
Accident Risk
Copyright Circadian Technologies, Inc. 2004
IMPACT ON TRAINING
Copyright Circadian Technologies, Inc. 2003
Copyright Circadian Technologies, Inc. 2004
Managing a Shiftwork Lifestyle TrainingManaging a Shiftwork Lifestyle Training
STUDY FROM KENNECOTT COLOWYO MINE:STUDY FROM KENNECOTT COLOWYO MINE:
After training on managing a shiftwork lifestyle, After training on managing a shiftwork lifestyle, employees at a mine site:employees at a mine site:– Increased daytime sleep by 1 hour Increased daytime sleep by 1 hour – Were less likely to stay awake for more than 18 consecutiveWere less likely to stay awake for more than 18 consecutive– Were more alertWere more alert– Had fewer gastrointestinal health issuesHad fewer gastrointestinal health issues– Found it easier to fulfill domestic responsibilities Found it easier to fulfill domestic responsibilities
2
Copyright Circadian Technologies, Inc. 2004
Managing Shiftwork Lifestyle TrainingManaging Shiftwork Lifestyle Training
Employees who provided lifestyle training had:Employees who provided lifestyle training had:– Lower rates of turnover compared to those that did notLower rates of turnover compared to those that did not– Lower rates of absenteeismLower rates of absenteeism– Had cost savings associated with these lower rates of $1,892 Had cost savings associated with these lower rates of $1,892
per employee per yearper employee per year
11.4%
7.6%
2.9%6.3%4.8% 4.5%
0%
4%
8%
12%
16%
No Training Training forShiftworkers
Training forShiftworkers and
Family
Tu
rno
ve
r/A
bs
en
tee
ism
Ra
te Turnover Absenteeism
Copyright Circadian Technologies, Inc. 2002
Addressing the Addressing the Extended Hours ChallengeExtended Hours Challenge
Copyright Circadian Technologies, Inc. 2004
Myth or Reality?Myth or Reality?
1. Fixed shifts (e.g. always working the night shift) are safer than rotating shifts.
2. As long as its voluntary, there is no evidence that demonstrates a clear upper limit on overtime hours.
3. Tired haul truck drivers (or other operators) can anticipate the onset of fatigue and take corrective actions to avoid it?
4. Long shifts (e.g. 12-hours or more) are less safe than traditional 8-hour shifts
5. Shiftworker training can measurably impact how shiftworkers spend off-duty time and family life.
Copyright Circadian Technologies, Inc. 2004
Elements of a Fatigue Management ProgramElements of a Fatigue Management Program
Fatigue Costs, Risks &
Liabilities
Management and Supervisor Education
Support Policies, Practices, and
Procedures
Pre-Employment Screening
Goodsleep.comWeb Counseling
Staffing Levels
Extended Hours Lifestyle Training + Support
Heath and Nutrition Programs
Sleep Disorder Screening and
Treatment
Alertness Recovery Strategies,
Environmental and Ergonomics
Practices
Bio-Scheduling
Optimization
Fatigue ManagementSystems
Copyright Circadian Technologies, Inc. 2004
For More InformationFor More Information
Upcoming symposiums:
Shiftwork – Health & Safety (American Airlines)
Developing alertness monitors (Fall 2004)
Circadian Technologies, Inc.
www.shiftwork.com