Copyright Circadian Technologies, Inc. 2002 Myths and Realities of Fatigue Circadian Technologies, Inc. 24 Hartwell Ave. Lexington, MA 02421 Phone: 781-676-6900

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


IMPACT OF FATIGUE



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.


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


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.)


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


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


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.


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


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


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


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


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



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


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)


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


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


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)


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



IMPACT ON SCHEDULING



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


Alertness Level

(MSLT)


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


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


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)



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


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


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)


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)


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)


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


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%


IMPACT ON ACCIDENT PREVENTION



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!


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


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


Microsleeps: Potholes on the Slope of Microsleeps: Potholes on the Slope of DrowsinessDrowsiness

TOTALINCAPACITY(Eyes closed)

IMPAIREDJUDGEMENT

Microsleeps

Alertness Level

ALERTNESS

SLEEPHours of driving


Microsleeps: Potholes on the Slope of Microsleeps: Potholes on the Slope of DrowsinessDrowsiness

TOTALINCAPACITY(Eyes closed)

IMPAIREDJUDGEMENT

Microsleeps

Alertness Level

ALERTNESS

SLEEPHours of driving


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


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


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


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


IMPACT ON TRAINING



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


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


Addressing the Addressing the Extended Hours ChallengeExtended Hours Challenge


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.


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


For More InformationFor More Information

Upcoming symposiums:

Shiftwork – Health & Safety (American Airlines)

Developing alertness monitors (Fall 2004)

Circadian Technologies, Inc.

www.shiftwork.com

[email protected]

Documents

Copyright Circadian Technologies, Inc. 2002 Myths and Realities of Fatigue Circadian Technologies, Inc. 24 Hartwell Ave. Lexington, MA 02421 Phone: 781-676-6900